Basic Suspension and Full Vehicle Analysis using

Basic Suspension and Full Vehicle Analysis using
Basic Suspension and Full Vehicle
Analysis using Adams/Chassis
ADM761 Course Notes
Europe
MSC.Software GmbH
Am Moosfeld 13
81829 Munich, Germany
Telephone: (49) (89) 43 19 87 0
Fax: (49) (89) 43 61 71 6
Part Number: ADAM*V2012*Z*CHAS*Z*SM-ADM761-NT
Corporate
MSC.Software Corporation
2 MacArthur Place
Santa Ana, CA 92707 USA
Telephone: (800) 345-2078
Fax: (714) 784-4056
Sep 2012
Asia Pacific
MSC.Software Japan Ltd.
Shinjuku First West 8F
23-7 Nishi Shinjuku
1-Chome, Shinjuku-Ku
Tokyo 160-0023, JAPAN
Telephone: (81) (3)-6911-1200
Fax: (81) (3)-6911-1201
Copyright 2012
MSC.Software Corporation
1
Legal Information
MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this
document without prior notice. The concepts, methods, and examples presented in this text are for illustrative and
educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or
design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect
damages resulting from the use of any information contained herein.
Copyright © 2012 MSC.Software Corporation. All Rights Reserved. This notice shall be marked on any reproduction of
this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the
prior written consent of MSC.Software Corporation is prohibited.
The MSC.Software corporate logo, Adams, Dytran, Easy5, Fatigue, Laminate Modeler, Marc, Mentat, MD Nastran, Patran,
MSC, MSC Nastran, Mvision, Patran, SimDesigner, SimEnterprise, SimManager, SimXpert and Sofy are trademarks or
registered trademarks of the MSC.Software Corporation in the United States and/or other countries. NASTRAN is a
registered trademark of NASA. All other trademarks belong to their respective owners.
Copyright 2012 MSC.Software Corporation
2
CONTENTS
Section
0
1
2
3
Page
Welcome to MSC.ADAMS/Chassis Training
About MSC.Software
S0-5
Getting Help
S0-6
Introduction
Virtual Prototyping Process
S1-4
What is ADAMS/Chassis
S1-8
Philosophy of ADAMS/Chassis
S1-11
Getting to know ADAMS/Chassis
S1-13
Setting ADAMS/Chassis Preferences
S1-19
ADAMS/Chassis Interface
Example Vehicles
S2-4
Half-Vehicle Events
S2-10
SDM Requests
S2-13
ADAMS/Chassis Coordinate System
S2-17
Fingerprints
S2-19
ADAMS/Chassis File Structure
Databases
S3-4
Systems
S3-6
Subsystems
S3-8
Property Files
S3-10
XML Data Format
S3-12
ADAMS/Chassis File Flow
S3-13
Copyright 2012 MSC.Software Corporation
3
CONTENTS
Section
4
5
6
7
8
Page
Changing Model Topology I
Hardpoints
S4-4
Standard Components (Part 1)
S4-7
Struts
S4-9
Stabilizer Bar
S4-12
Attachment Options
S4-16
Changing Model Topology II
Standard Components (Part 2)
S5-4
Jounce Bumper
S5-10
Rebound Bumper
S5-11
Construction Options
S5-12
Determining Component Loads
Parts
S6-4
Static Loadcase Event
S6-9
Effect of Passengers on Full-Vehicle Response
Loading Subsystems
S7-4
Static Vehicle Characteristics (SVC) Event
S7-7
Frequency Response Event
S7-10
Tire Modeling
Tire/Wheel Setup
S8-4
Tire Modeling
S8-7
Constant Radius Analysis
S8-11
Copyright 2012 MSC.Software Corporation
4
CONTENTS
Section
9
10
11
12
Page
Instrumenting the Model
Instrumentation Subsystem
S9-4
Two-Part Body Construction Option
S9-8
Swept Steer Full-Vehicle Event
S9-11
Using Optional Subsystems
Brake Subsystem
S10-4
Powertrain Subsystems
S10-8
Controls Subsystem
S10-12
Additional Rear Suspensions
S10-15
Straight-Line Deceleration Event
S10-18
Open-Loop Braking Event
S10-19
Integration with ADAMS/Insight
What is ADAMS/Insight
S11-4
Recent Design Advances
S11-7
DOE Theory and Response Surfaces
S11-11
Creating User Responses in ADAMS/Chassis
S11-12
ADAMS/Chassis Improve Mode
S11-17
Introduction to Customization with ADAMS/Chassis
ADAMS/Chassis Pre-Processing Flow
S12-4
ADAMS/Chassis Modeling Customization
S12-7
ADAMS/Chassis Event Customization
S12-11
ADAMS/Chassis Plotting Customization
S12-14
Custom ADAMS/Solver Library
S12-16
Copyright 2012 MSC.Software Corporation
5
CONTENTS
Section
13
Page
Adams/Chassis Flex Body Integration Improvements
Adams/Chassis Flex Body Integration Improvements
S13-4
Adams/Chassis Flex Body Generation Utility
S13-5
Adams/Chassis Flexible Parts editor
S13-8
Copyright 2012 MSC.Software Corporation
6
WELCOME TO
Adams/CHASSIS TRAINING
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-1
Course Objectives
• After taking this course you will be able to:
– Navigate the Adams/Chassis interface and file structure
– Investigate the different modeling methods available and options available for
controlling the topology in Adams/Chassis
– Determine how various vehicle design and loading changes affect the
characteristics of a vehicle
– Investigate the various instrumentation options Adams/Chassis offers to aid in
model correlation.
– Integrate Adams/Chassis with Adams/Insight for design of experiments
– Integrate flexible bodies in Adams/Chassis
– Use customization with Adams/Chassis
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-2
WELCOME TO Adams/CHASSIS TRAINING
•
Adams/Chassis provides a complete analysis environment
for automotive Adams analysis. Adams/Chassis does this
by providing:
–
–
–
Standard model types
Two analysis types
Post-processing
You run Adams/Chassis in conjunction with Adams/Solver and
Adams/PostProcessor. In this course, you learn how the
Adams/Chassis interface and file structure work, how to change
model topology, how to determine component loads, and how to
instrument a model.
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-3
WELCOME TO ADAMS TRAINING
• What’s in this section:
–
–
–
–
What is Adams?
Adams Applications
SimCompanion: Technical Articles, Documentation & Forums
Getting Help
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-4
WHAT IS ADAMS?
• Automatic Dynamic Analysis of Mechanical Systems
• Development started in 1974 at the University of Michigan
• Mechanical Dynamics, Inc. started with Adams/Solver
• MDI was acquired by MSC in 2002
• Euler-Lagrange method to create equations of motion
• Predictor-corrector methods to solve equations
• Integrated animation and plotting
• Powerful parametric, scripting and post-processing abilities
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-5
ADAMS APPLICATIONS
• The general purpose graphical user interface is Adams/View
– Model building, simulation submission, some animation
• Equations are built and integrated with Adams/Solver
– Solver is a standalone application, but typically used seamlessly from within
Adams/View
• Plotting and animation done with Adams/PostProcessor
– Tightly integrated with Adams/View
• Industry verticals (e.g., Adams/Car) for model templates
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-6
SimCompanion
• One stop for full online
support
• Find answers to your
questions
• Search across ALL content
• Subscribe to email
notification
• Single sign-on to ALL
content
• Access to other support
resources
– Case Management Portal
– Discussion Forums
– Training Information
http://simcompanion.mscsoftware.com
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-7
SimCompanion
• Personalized Support via the
following channels
– Web
• Submit a Case Online
• Manage Cases
– Email
• List of Addresses in Support
Contact Information
– Phone
• List of Phone Numbers in
Support Contact Information
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-8
SimCompanion
• Product Info and Docs
– Access to all Product Documentation
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-9
SimCompanion
• Access to
Communities
– VPD
Community
Discussion
Forums
– Subscribe to
discussion
communities of
interest
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-10
simcompanion.mscsoftware.com
GETTING HELP – ONLINE HELP
• Online Help
– To access the online help, do either of the following:
• From the Help menu, select Adams/Chassis Help to display the home page for
the Adams/Chassis online help.
• On Windows, go to Start->Programs->MSC.Software->Adams 2012->Adams
Online Help
• While working in any Adams/View dialog box, press F1 to display online help
specific to that dialog box.
– Once the online help is displayed, you can browse the table of contents, use
the index, or search for keywords.
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-11
GETTING HELP – ONLINE HELP
Index/search entire
Adams help
Contents of
selected tab
Table of contents
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-12
GETTING HELP – CONSULTING
• MSC.Software provides comprehensive engineering consulting services
to help you realize the benefits of Virtual Product Development quickly
and confidently.
–
–
–
–
–
Staff Augmentation
Technology Transfer
Process Capture and Automation
Methods Development
Virtual Build and Test
• For more information on MSC Consulting Services, go to:
http://www.mscsoftware.com/Contents/Services/Consulting-Services/
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-13
ADM761, Section 0, September 2012
Copyright 2012 MSC.Software Corporation
S0-14
SECTION 1
INTRODUCING Adams/CHASSIS
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-1
INTRODUCING Adams/CHASSIS
 In this section, you will get familiarize with the Adams/Chassis
interface and understand the product’s relationship to the virtual
prototyping process. You will exercise the left and right wheel
centers of a front suspension subsystem to their jounce and
rebound position, and analyze the effects of static wheel
alignment properties.
 What does this section contain?




Virtual Prototyping Process
What is Adams/Chassis?
Philosophy of Adams/Chassis
Setting Adams/Chassis Preferences
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-2
VIRTUAL PROTOTYPING PROCESS
Design
Problem
Cutting time &
costs
Build
Increasing
quality
Review
Test
 Build a model of your design using:





Bodies
Forces
Contacts
Joints
Motion generators
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
Increasing
efficiency
S1-3
Improved
Product
Improve
VIRTUAL PROTOTYPING PROCESS
Design
Problem
Cutting time &
costs
Build



Measures
Simulations
Animations
Plots
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
Increasing
efficiency
Review
Test
 Test your design using:

Increasing
quality
Improved
Product
Improve
 Validate your model by:

Importing test data

Superimposing test data
S1-4
VIRTUAL PROTOTYPING PROCESS
Design
Problem
Cutting time &
costs
Build
Increasing
quality
Review
Test
 Review your model by adding:




Friction
Flexible Parts
Forcing functions
Control Systems
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
Increasing
efficiency
Improve
Iterate your design through
variations using:


S1-5
Improved
Product
Parametrics
Design Variables
VIRTUAL PROTOTYPING PROCESS
Design
Problem
Cutting time &
costs
Build


Improved
Product
Improve
 Automate your design
using:
DOEs
Optimization



ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
Increasing
efficiency
Review
Test
 Improve your design
using:
Increasing
quality
S1-6
Custom menus
Custom dialog boxes
Macros
WHAT IS Adams/CHASSIS?
 Adams/Chassis provides:


A complete analysis environment for automotive virtual prototyping.
It does this by providing standard model types, two analysis types,
and postprocessing.
A library of subsystem and component modeling techniques, along
with a library of standard analysis types.
 Adams/Chassis uses the Virtual Prototyping Process to:
Build
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
Review
Test
S1-7
Improve
Improve
WHAT IS Adams/CHASSIS?
 Adams/Chassis runs in conjunction with Adams/Solver and
Adams/PostProcesser. This includes:



Preprocessing
Simulation
Postprocessing
– Note: Adams/Chassis is not a process, but a tool that fits within the
automotive design process. The diagram on the next page shows the
Functional Digital Vehicle.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-8
WHAT IS Adams/CHASSIS?
 Functional Digital Vehicle
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-9
PHILOSOPHY OF Adams/CHASSIS
 Adams/Chassis provides you with an extensive library of proven
modeling methods for subsystems and components. We work
with the Adams/Chassis users to continuously expand the
library of proven modeling methods.
 You can examine and modify the following open-source
methods:




Pre-processing
Events
Plotting
Reports
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-10
PHILOSOPHY OF Adams/CHASSIS
 Advantages of using Adams/Chassis



Provides a standard approach for vehicle modeling.
Allows you to build complex Adams models while maintaining a
minimum set of parameters.
Provides a simple interface to powerful Adams/Solver technology to
enhance your model. With Adams/Chassis, you can start analyzing
Vehicle Dynamics/Durability immediately.
 Integration with other Adams Products

Adams/Chassis is a vertical product, which means that it integrates
with other Adams Products. Adams/Chassis simplifies the use of
these Adams Products:
•
•
•
•
Adams/Solver
Adams/View
Adams/PostProcessor
Adams/Insight
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-11
GETTING TO KNOW Adams/CHASSIS
 Adams/Chassis Work Modes

Adams/Chassis is divided into four work modes:
•
•
•
•

Build
Test
Review
Improve
Build:
• The Build mode allows you to edit model data and change system
configuration. You can also work on multiple models at once. The Build
mode is default for starting Adams/Chassis.

Test:
• The Test mode allows you to build and run your model.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-12
GETTING TO KNOW Adams/CHASSIS
 Adams/Chassis Work Modes (CONT.)

Review:
• The Review mode allows you to visualize analysis results using
Adams/PostProcessor. You can postprocess the output of standard
Adams/Chassis events. Postprocessing has two formats: reports and plots. A
majority of standard Adams/Chassis events have either a report, a plot, or
both. You can also create an animation of your event.

Improve:
• The Improve mode allows you to refine models with Adams/Insight. Here you
can use the features from Adams/Insight to create sophisticated experiments
for measuring the performance of your model. It also provides a collection of
statistical tools for analyzing the results of your experiments so that you can
better understand how to refine and improve your model.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-13
GETTING TO KNOW Adams/CHASSIS
 Getting to know the Toolbars

The toolbars in Adams/Chassis change according to the work
mode. Below is the basic toolbar that is available in all work modes.
Toggle toolbar on/off
Build Mode
Test Mode
Review Mode
Improve Mode
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-14
GETTING TO KNOW Adams/CHASSIS

The following figures show the toolbars that are available in
each work mode:
New Model
Load Model
Write Report
Delete Model
Build Mode Toolbar
Graphical difference
Build and Run Selected Events
Test Mode Toolbar
Graphical difference
Run Selected Events
Build Selected Events
Delete Selected Events/ fingerprints
Copy selected events
Save Selected Fingerprint
Load Fingerprint
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
New Fingerprint
S1-15
GETTING TO KNOW Adams/CHASSIS

The following figures show the toolbars that are available in
each work mode:
Delete Custom Postprocessing Events
Review Mode Toolbar
Execute Selected Plots
Graphical Difference
Execute Selected Reports
Execute Selected Animations
Load Custom Postprocessing Event
Improve Mode Toolbar
Graphical Difference
Remove Selected Events from selected Investigation
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-16
GETTING TO KNOW Adams/CHASSIS
 Getting to know the Treeview

The Adams/Chassis treeview changes according to the work mode.
The treeview has different features in each work mode. Below are
the two basic sections of the treeview:
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-17
SETTING Adams/CHASSIS PREFERENCES
 You can set Adams/Chassis preferences to define the work
environment specific to the machine you are using. Before
running Adams/Chassis, you must either set up the preferences
or load an existing preferences file. Incorrect preference settings
can prevent Adams/Chassis from performing even the most
basic functions.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-18
SETTING Adams/CHASSIS PREFERENCES
1
2
3
4
5
6
7
8
9
10
12
11
18
13
14
15
16
17
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-19
SETTING Adams/CHASSIS PREFERENCES

You must consider the following options
1.
Current Working Directory - Directory where all Adams/Solver-related
files are created. The default is the directory from which Adams/Chassis
was started.
Note: This directory should already exist and have no spaces in its path
2.
Shell Startup Command - A command that launches a new window or
shell for displaying messages or launching programs.
3.
Text Editor Command - Program that allows viewing and editing of ASCII
files and displays result files.
4.
Graphical Difference Command: A command to launch the graphical
differencing tool that allows you to compare two ASCII files. For example:
SGI/usr/sbin/gdiff, Windows 3rd party ExamDiff, and others. This tool is
useful in understanding how Adams/Chassis works and troubleshooting
modeling and customization.
5.
Temporary Files Directory - Directory where scratch files will be written.
Directory must already exist and have no spaces in its path.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-20
SETTING Adams/CHASSIS PREFERENCES
6.
Matlab Command – Location for Matlab execution files.
7.
Personal .py File Options - Locations where Adams/Chassis will look for
customized files. (This will be discussed later in the course.)
8.
Custom Event Options - Locations where optional custom events are
found.
9.
Solver Command - A command to use Adams/Solver libraries, and to
create a path to custom Adams/Solver libraries.
• Default - Select to use the standard Adams/Chassis solver executable that is
distributed with the installation. Unless you need to run your own custom
executable, you should always use the Default setting.
• Other - Select if you have created your own solver subroutines and have created
your own custom Adams/Chassis solver executable. The command to include is
achassis –custAdams <path to custom executable>.
10. Animation Tool - A program to use to view animated results.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-21
SETTING Adams/CHASSIS PREFERENCES
11. Solver Preference - Choose which version of Adams/Solver to use:
• None - Adams/Chassis selects the solver it feels is best suited to individual fullvehicle events. For Version 2003, this remains Adams/Solver (FORTRAN) for all
events.
• C++ - Forces Adams/Chassis to use the C++ Solver for all full vehicle events.
• FORTRAN - Forces Adams/Chassis to use the Adams/Solver (FORTRAN) for all
full-vehicle events.
12. Plotting Tool - Choose a program used to view plotted results:
• PPT - Uses Adams/PostProcessor to view plotted results.
• Other - Uses a different plotting tool that reads Adams request (.req) files. You
can specify the path to that executable and Adams/Chassis launches the plots
from the Review Mode in the specified application.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-22
SETTING Adams/CHASSIS PREFERENCES
13. Use Advance Human Graphics - Replaces each generic block-shaped
occupant graphic that is active in the Occupants subsystem with outline
graphics of humans. Adams/Chassis adds outline graphics code to the
dataset (.adm) file. If you have more than one occupant active in your
model, you may notice a slight performance penalty loading and animating
your simulation. It is recommended that for general animation purposes
that you use the generic occupant graphics.
14. Create Backup Files - Creates backup copies of changes to your system,
subsystem, and component files.
15. Review Mode animate/plot/report Toggle Default On - Sets the default
toggle setting for all available postprocessor utilities to On for every
successful simulation in Review mode.
16. Use Road Graphics - Uses advanced road graphics (available for some
full-vehicle events, such as double-lane change) for animation purposes.
17. Database registration - Allows the paths to several vehicle databases to
be identified using short names.
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-23
SETTING Adams/CHASSIS PREFERENCES
18. Thread Count- Available for Adams/Solver (C++).
Specify the number of parallel threads that Adams/Solver (C++) uses
when performing the simulation. The number of threads, n, must be an
integer in the range of 1 to 8. The default value is 1. By executing multiple
threads in parallel across multiple processors, Adams/Solver (C++) can
reduce the walltime required for a simulation.
Typically, the optimal number of threads is between N and 2N, where N is
the number of processors (including virtual processors in the case of
Pentium processors with HyperThreading enabled).
ADM761, Section 1, September 2012
Copyright 2012 MSC.Software Corporation
S1-24
SECTION 2
Adams/CHASSIS INTERFACE
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-1
Adams/CHASSIS INTERFACE
 What does this section contain?






Example Vehicles
Half-Vehicle Events
SDM Requests
Adams/Chassis Coordinate System
Fingerprints
Workshop 2: Adams/Chassis Interface
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-2
EXAMPLE VEHICLES
 The Adams/Chassis installation contains an extensive library of
ready-to-use vehicle models. The following parameters have
been defined for several commonly used vehicle configurations:



Suspension and steering type
Spring, damper, and bushing properties
Tire/road interface models
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-3
EXAMPLE VEHICLES (CONT.)

The achassis_gs model you used in Workshop 1 is one of the
examples in the vehicle database library. All example databases
are found in <achassis_top>\examples\vehicles\. The directory can
be quickly accessed by using the Example Vehicles shortcut which
is shown below.
For more information on
features of the various
example vehicles, see:
http://support.mscsoftware.c
om/kb/results_kb.cfm?S_ID
=1-KB9773
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-4
EXAMPLE VEHICLES (CONT.)
 The following is a list of the basic front and rear suspension and
steering types available without customization.
 Front







Front 4 Link
Hotchkiss
MacPherson
Multilink
SLA (short-long arm)
SLA (with torsion bar)
Twin I-Beam
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-5
EXAMPLE VEHICLES (CONT.)
 Rear












3 Link
4 Link Multilink
4 Link Panhard
4 Link Watts
Central Link
Hotchkiss
Integral Link
Multilink
Rear MacPherson LCA
Solid Axle Trailing Arm
Quadralink Strut
Semi Trailing Arm
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation









S2-6
Quadralink Strut
Semi Trailing Arm
Quadralink UCA
Semi Trailing Arm Shack
SLA Coil
SLA Inverse LCA
SLA Trail
SLA Pendulum
Twist
EXAMPLE VEHICLES (CONT.)
 Steering Gear





Haltenberger
Pitman arm
Rack 4 wheel steer
Rack and pinion
Relay Rod
 Steering Column



Advanced
Swing link
Tilt bracket
You may find images of the basic front and rear suspension and
steering types listed above in the Adams/Chassis online help.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-7
EXAMPLE VEHICLES (CONT.)


Most of the current vehicles use subsystem configurations that are
represented in the list of examples. However, you are not limited to
this list. You can customize Adams/Chassis to include new designs
that are not represented by one of the examples.
The following are all open source and you can customize the
methods behind them:
•
•
•

Chassis Pre-Processing
Events
Plotting
As new designs become widely used, the Adams/Chassis
subsystem library is expanded to benefit the user community.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-8
HALF-VEHICLE EVENTS
 Adams/Chassis includes a standard set of simulations or events
that you can use to exercise your model. The events are divided
into two types: half vehicle (front only or rear only) and fullvehicle (front and rear). You can also customize the events if
you want to exercise your model using an event that is not one
of the standard events.
Adams/Chassis includes the following half-vehicle events:


Dynamic loadcase - Determines loads acting on the chassis and
body or frame of a vehicle due to dynamically varying force,
moment, and displacement inputs.
Ride motion - Exercises wheels in jounce and rebound to produce
toe/caster/camber curves, wheel rate, and so on. This is the
traditional starting point for suspension design and analysis.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-9
HALF-VEHICLE EVENTS (CONT.)





Roll motion - Calculates roll rate based on the given axle load and
left and right force difference.
Roll motion (displacement based) - Calculates roll rate based on
left and right opposite wheel displacement. Single wheel motion Same as ride motion, but only one wheel is displaced.
Static load case - Analyzes vehicle characteristics and loads
acting on the chassis and body or frame due to static loads that are
placed at the wheel centers and at the tire patches.
Steering - Evaluates steering kinematics, such as Ackerman, and
overall steering ratio.
Suspension compliance - Evaluates suspension compliance
under various loading conditions, and calculates lateral compliance
steer, lateral camber compliance, wheel recession, and longitudinal
compliance steer.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-10
HALF-VEHICLE EVENTS (CONT.)

SVC half suspension - Calculates ground reactions, suspension
rise, anti lift/drive, vehicle mass and inertia, wheel rates, and
suspension compliance.
You can find more information in the Adams/Chassis online help.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-11
SDM REQUESTS
 The ride motion event is often used to correlate the
Adams/Chassis model with an actual K&C (kinematics and
compliance) test. The event calculates wheel rate and several
other SDM (Suspension Design Module) requests.
 The complete list of SDM requests along with the Request ID
corresponding to each is shown on the next page, you can also
find it in the Adams/Chassis online help.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-12
SDM REQUESTS (CONT.)
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-13
SDM REQUESTS (CONT.)
 Adams/Chassis uses equations based on a compliance matrix
to calculate each of the requests. Below is an example matrix.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-14
SDM REQUESTS (CONT.)
 The example shows that C(3,3) is the amount of left wheel
vertical displacement due to a unit force applied to the left wheel
in the vertical direction. C(3,9) is the vertical motion of the left
wheel center due to a unit vertical force applied at the right
wheel center. For an independent suspension without a
stabilizer bar, C(3,9) is zero since a vertical force on the right
wheel will not cause motion of the left wheel. Left wheel rate is
then calculated as 1 / [C(3,3) + C(3,9)].
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-15
Adams/CHASSIS COORDINATE SYSTEM
 The following is an example of the Adams/Chassis coordinate
system.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-16
Adams/CHASSIS COORDINATE SYSTEM
(CONT.)
 The origin is located some where in front of the
vehicle with Y=0 as the centerline and Z=0 some
where below the vehicle. Because the wheel and
tire sizes vary, Z=0 does not correspond with the
ground patch for a particular tire. The result of
choosing Z=0 to be below the vehicle is that you
will not have negative Z values when describing
the vehicle geometry.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-17
FINGERPRINTS
 Adams/Chassis uses fingerprints as a way to use a series of
events to capture unique characteristics of a model.
 When saved, fingerprints store all of the events, event
parameters, vehicle databases, and vehicle configuration files
as you specified them. Fingerprints do not save modeling
information, but do save which models are being used and how.
Fingerprint files have the extension .xml and can be saved or
opened in a few ways.
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-18
FINGERPRINTS (CONT.)
 You can use fingerprints to:

Test one model with several different events

Compare the performance of several models using the same event

View any combination of models and events
 Below are the tools that relate to fingerprints
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-19
Test Mode Toolbar
Build and Run Selected Events
Graphical difference
Run Selected Events
Build Selected Events
Delete Selected Events/ fingerprints
Copy selected events
Save Selected Fingerprint
Load Fingerprint
New Fingerprint
ADM761, Section 2, September 2012
Copyright 2012 MSC.Software Corporation
S2-20
SECTION 3
Adams/CHASSIS FILE STRUCTURE
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-1
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-2
Adams/CHASSIS FILE STRUCTURE
 What does this section contain?

Databases

Systems

Subsystems

Property Files

XML Data Format

Adams/Chassis File Flow

Bushings
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-3
DATABASES
 Vehicle Database (.vdb)


Each model's data is stored in a Vehicle
Database (.vdb). A database is a file folder or
directory with the extension .vdb. The database
contains sub directories, also called tables
(.tbl), for different file types.
Databases can be organized to represent:
•
•
•
•
One vehicle
One vehicle program (with variants)
Common components shared by multiple
programs (department-wide library)
Corporate libraries (tires, shocks, bushings, and
so on.)
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-4
DATABASES (CONT.)

There are three major classes of files in the database:
•
•
•

System (stored in system.tbl)
Subsystem (stored in subsystems.tbl)
Property (several tables are possible)
The diagram below shows the file relationship
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-5
SYSTEMS
 System files are also known as Vehicle Configuration Files. They are
stored in <model>.vdb/ systems.tbl. System files are the first step in
visual data editing. There are three types of systems in
Adams/Chassis: front, rear, and full.
 System files contain:

Subsystem References - Found in the Subsystem Definition tab in the
system editor. Subsystem references include:
•
•

References required and any optional subsystems
Optional geometry offset to shift entire subsystem in space
System Parameters - Aspects that affect the model but are not related to a
particular subsystem. These are found in the Properties tab in the system
editor. System parameters include:
•
•
•
Integrator parameters
Ground height, gravity
Optional requests
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-6
SYSTEMS (CONT.)
Subsystem References
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
System Parameters
S3-7
SUBSYSTEMS
 Subsystem files


Subsystem files are stored in <model>.vdb/subsystems.tbl. They
are analogous to the old Adams/Pre data files (.fst, .sst, .rst, and so
on).
The primary contents of subsystem files include:
•
•
•
•
•
•
Hardpoints
Parts
Connectors (bushings)
Property file references
Construction options
Subsystem parameters (if applicable)
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-8
SUBSYSTEMS (CONT.)
 Subsystem types:







Body
Front suspension
Front wheel and tires
Steering gear
Steering column
Rear suspension
Rear wheel and tires
Below are optional items:
●
●
●
●
Loading
Instrumentation
Powertrain
Brakes
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
●
●
S3-9
Controls
Additional rear
suspensions (trailers)
PROPERTY FILES
 Property files represent data for a particular component. Property
files contain:

Object attributes

Spline data

Parts

Connectors
● Property files can also reference other property files (for example,
stabilizer bar property file references a bushing property file for the
mounts).
● After Adams2007r1, the property files has been merged into
subsystem file. Here is the knowledge base article,
ACH-001: Using Property Files Merged into Subsystems
http://support.mscsoftware.com/kb/results_kb.cfm?S_ID=1-43315518
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-10
PROPERTY FILES (CONT.)
 Property file types

Following is a list of property file types and their locations in
the database:
●
●
●
●
●
●
●
●
●
●
●
Aerodynamic forces - aero_forces.tbl
Bumpstops - bumpstops.tbl
Bushings - bushings.tbl
Dampers - dampers.tbl
Drivetrain differentials - differentials.tbl
Powertrain data - powertrains.tbl
Rebound stops - reboundstops.tbl
Springs - springs.tbl
Stabilizer bars - stabilizer_bars.tbl
Steering assistants - steering_assists.tbl
Tire models - tires.tbl
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-11
XML DATA FORMAT
 Three file classes (system, subsystems, and property files) are
stored using the XML (Extensible Markup Language) data
format. Therefore, all of the files have an .xml extension.
 XML Advantage

The XML files are text based, but they have tags that are used to
define context of data. These tags are similar to tags used to define
context of text in HTML. The files can be viewed in any text editor
or Web browser. The advantages of using XML include:
•
•
•
Operating system independence
Self-documenting
You can use third-party tools for viewing and editing. Adams/Chassis
can be considered an XML editor.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-12
Adams/CHASSIS FILE FLOW
 Adams/Chassis Pre-Processing file flow:
 Review of basic MSC.Adams terminology



Adams/Solver - The solution engine.
Adams/Solver deck (*.adm file) - The actual ASCII file submitted to
Adams/ Solver.
Adams/Solver command (*.acf file) - An ASCII file that contains
commands to control how Adams/Solver runs the model.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-13
Adams/CHASSIS FILE FLOW (CONT.)
 Review of basic MSC.Adams terminolgy (Cont.)

Adams/Solver output files
•
•
•
•
•
Graphics (*.gra file) – Contains information on how graphics work.
Request (*.req file) – Contains output for a user-defined set of results.
Results (*.res file) – Contains state results for every entity.
Message (*.msg file) – Contains information about the
solver/simulation/ problems.
Output (*.out file) – Contains initial conditions and request; content can
depend on output specifications.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-14
Adams/CHASSIS FILE FLOW (CONT.)
 Because simulations run in Adams/Solver, the chart below shows the
Adams/Chassis simulation file flow.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-15
BUSHINGS
 A bushing is a specialized type of connector in Adams/Chassis.
A connector describes the interface between two parts in the
model. Bushings represent a compliance between two parts with
stiffness and damping parameters specified in up to three
translational and three rotational directions. Besides bushings,
connectors can be:

Constraints
•
•
•
•

Fixed
Revolute
Hooke
Spherical
Free (no connection)
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-16
BUSHINGS (CONT.)
 Types of Bushings

There are five types of bushings classified based on the method of
the force-displacement definition. They are:
•
•
•
•
Linear
Piecewise nonlinear
Spline nonlinear
Spline nonlinear with hysteresis
 Linear

The linear type bushing uses the Adams/Solver FIELD statement,
but it is analogous to using a BUSHING statement. You can
combine linear components with each of the three nonlinear
bushing types.
BUSH/1104112,I=1181112,J=1104112
, K =5256.0,5256.0,5256.0
, C = 50.00, 50.00, 25.00
, KT =0.00000e+000,0.00000e+000,0.00000e+000
, CT =0.00000e+000,0.00000e+000,0.00000e+000
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-17
BUSHINGS (CONT.)
 Piecewise nonlinear

The Piecewise nonlinear bushing uses a FIELD statement with an
ARRAY defining the force-displacement profile using slopes and
breakpoints.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-18
BUSHINGS (CONT.)
 Spline nonlinear

The spline nonlinear bushing uses a GFORCE statement with a
SPLINE defining the force-displacement data points with an
AKISPL function interpolation.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-19
BUSHINGS (CONT.)
 Spline nonlinear with hysteresis


The spline nonlinear with hysteresis bushing uses a custom FIELD
statement with two different spline nonlinear curves. One curve
represents the force-displacement profile with movement in a
positive direction while another curve represents the forcedisplacement profile in the negative direction.
For each of the four types of bushings described above, the
damping relationship in any or all six directions may be defined as a
linear damping coefficient or a spline force-velocity profile.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-20
BUSHINGS (CONT.)
 Bushing orientation

Each bushing in your system has a default orientation, defined by the
subsystem template. You can override this orientation and provide
your own by selecting Specify Orientation in the Orientation property
dialog box. You then have the choice of specifying euler angle or ZPXP type orientation.
NOTE: The ZP and XP
orientation points are
specified relative to the
location of the bushing, in
the global reference frame.
This is different than the
MARKER statement where
ZP and XP were relative to
the part coordinate system.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-21
BUSHINGS (CONT.)
 Bushing subsystem/property file distinction

Parameters related to bushings, or any other components in
Adams/Chassis, are often stored in the subsystem and property
files. Information intrinsic to the component is stored in the property
file. Information related to how the component is used is stored in
the subsystem file. The best way to be sure which one you are
editing is by looking at the Current Active File text box in the
property editor. This shows you exactly which file you are editing.
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-22
BUSHINGS (CONT.)
 Property file

Stiffness characteristics

Damping characteristics

Graphics - height, radius
 Subsystem File

Scale factors

Orientation
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-23
ADM761, Section 3, September 2012
Copyright 2012 MSC.Software Corporation
S3-24
SECTION 4
CHANGING MODEL TOPOLOGY I
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-1
CHANGING MODEL TOPOLOGY I
 In this module you investigate the different options available for
controlling the topology and location of stabilizer bar
connections.
 What does this section contain?





Hardpoints
Standard components (Part1)
Struts
Stabilizer Bars
Attachment Options
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-2
HARDPOINTS
 Each subsystem model has a basic topology that distinguishes it
from the other models. Adams/Chassis has built-in features that
allow you to personalize each model to meet your requirements.
We will look at three of these features to personalize model
topology:

Hardpoints - Where are the connections?

Attachment Options - Which parts are connected?

Construction Options - How are the parts connected?
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-3
HARDPOINTS (CONT.)
 Hardpoints define:



Key locations in the subsystem
Point where different parts connect
Points where force elements (for example spring or shock) connect
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-4
HARDPOINTS (CONT.)
 The Adams/Chassis online help contains a diagram of each
subsystem type and all hardpoint locations. Below is an
example of a hardpoint diagram.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-5
STANDARD COMPONENTS (PART 1)
 The standard components discussed here include:

Shocks

Struts
 Shocks


Shocks are modeled as two parts on a slider. The ends are rigidly
connected either by a Hooke joint and a spherical joint, or using
bushings, if necessary.
Shock property files also contain the damping specification. There
are three methods of defining the force versus velocity profile:
• Linear damping coefficient
• nonlinear spline of force versus velocity data
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-6
STANDARD COMPONENTS (PART 1) (CONT.)
– Property files are stored in the dampers.tbl directory of the vehicle
database. You can access the damper editor through the dampers
table in the subsystem editor.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-7
STRUTS
 Struts are specialized dampers that are designed to take
bending and damping loads in the suspension. The same two
damping definition options are available for a strut that are
available for a shock. The strut includes the following options for
modeling the bending stiffness:

Rigid (no bending)

Simple Bending

Complex Bending
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-8
STRUTS (CONT.)
 Simple bending

You specify the upper strut length, lower strut length, and
bending stiffness.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-9
STRUTS (CONT.)
 Complex bending

Complex bending includes many levels of structural
compliance. It contains six parts connected through several
stiffness parameters.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-10
STABILIZER BARS
 There are two types of stabilizer bars:


Simple stabilizer bar
Beam-element stabilizer
 Simple stabilizer bar

In the simple stabilizer bar example below, the end links are
modeled as springs. You can specify link stiffness and damping.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-11
STABILIZER BARS (CONT.)

In this next example, the end links are modeled as rigid parts. You
can specify link mass and inertia. The rotational spring stiffness is
controlled by setting the equivalent torsional stiffness of the bar.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-12
STABILIZER BARS (CONT.)
 Beam-element model

The beam element model is more accurate than simple models.
Adams/Solver beam and part elements are combined to create a
nonlinear representation of the stabilizer bar. You use the following
parameters:
• Diameter
• Wall thickness
• Young's modulus
• Poisson's ratio
• Density
• Centerline XYZ profile
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-13
STABILIZER BARS (CONT.)
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-14
ATTACHMENT OPTIONS

Standard subsystems come with flexibility for a component
attachment. Adams/Chassis provides control for the parts that
are attached to the following components:
– Springs
– Dampers
– Bumpers
– Stabilizer bars

Each component tab in the subsystem editor displays a list of
allowed attachment parts. Remember that attachment parts are
not intrinsic to the component property so they are stored in the
subsystem file.
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-15
ATTACHMENT OPTIONS (CONT.)
ADM761, Section 4, September 2012
Copyright 2012 MSC.Software Corporation
S4-16
SECTION 5
CHANGING MODEL TOPOLOGY II
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-1
CHANGING MODEL TOPOLOGY II
 What does this section contain?

Standard Components (Part 2)

Jounce Bumper

Rebound Bumper

Construction Options
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-2
STANDARD COMPONENTS (PART 2)
 The standard components covered here are:

Springs

Jounce bumper

Rebound bumper
 Springs

Because different vehicles use different methods of springing
each wheel, Adams/Chassis offers four of the most common
spring models. All spring property files are stored in the spring.tbl
directory of the vehicle database. The four spring models are:
• Coil
• Torsion
• Air
• Leaf
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-3
SPRINGS
 Coil Springs

Coil springs can be linear or nonlinear.

Linear properties:
• Constant rate (force/length unit)
• Free length

Nonlinear spline:
• Independent axis - Either distance between spring seats or
deflection from initial configuration
• Dependent axis - Force in spring at independent axis value
Preload is calculated by considering the following:
• Initial distance between spring seats
• Specified install length
• Specified preload

You can also specify a second set of springs.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-4
 Torsion springs

SPRINGS (CONT.)
Torsion springs come with the following parameters:
• Material properties (modulus, Poisson’s ratio, density)
• Inner/outer radius
• Active length
• Finish angle – used to adjust ride height
 Air Springs

Air springs have the following properties:
• Trim length
• Trim load

Force-Deflection 3D Spline
• X Values – Deflection in air spring
• Z Value – Trim load
• Y Value – Force in air spring at X and Z value
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-5
 Leaf springs

SPRINGS (CONT.)
Two leaf spring models are outlined below:
• SAE 3 link model
• Beam-element model
 SAE 3 link model

The SAE 3 link model is an approximate model. The stiffness is defined
by three torsional stiffness components for the front and rear section of
the model.
• KT(x) = Longitudinal twist stiffness of the (front or rear) section of the
spring. This parameter is important for roll stiffness.
• KT(y) = Lateral bending stiffness of the (front or rear) section of the spring.
This value is important for the lateral stiffness of the suspension.
• KT(z) = Vertical bending stiffness of the (front or rear) section of the spring.
This value is important because it defines the spring rate of the spring.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-6
SPRINGS (CONT.)
 SAE 3 link model (Cont.)

The second stage, or helper spring, can be defined as a linear or
nonlinear force vs. displacement profile.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-7
SPRINGS (CONT.)
 Beam element model

The beam element model is a more accurate model than the
SAE 3 link model. The leaf spring free profile is entered and
the leaf is modeled as a series of beams and parts. It
contains the Makeleaf process:
●
Leaf exercised to design load
●
Leaf spring template created at design load
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-8
JOUNCE BUMPER
 The jounce bumper contains the following:

Metal-to-metal rate parameter

Optional damping (rate or spline)

Metal-to-metal contact that can be in separate location

Point 75 at mount location, not bottom of bumper

Polynomial or spline force method
 The polynomial is defined by:
Where
●
a is the linear rate
●
b is the quadratic rate
●
c is the cubic rate defined in the
jounce bumper editor.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-9
REBOUND BUMPER
 The rebound bumper contains:

Metal-to-metal rate parameter

Optional damping

Free length, which determines when bumper is activated

Polynomial or spline force method
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-10
CONSTRUCTION OPTIONS
 Construction options allow you to change how
different components are modeled or how they are
attached. This is another example of how
Adams/Chassis offers modeling flexibility without
extensive customization.
 Constructions options offer:

Different modeling methods for subsystems and
components

Variation without customization

Most construction options available in your subsystem files

Option to add other construction options
NOTE: The Adams/Chassis online help contains additional information that is
helpful when using construction options.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-11
CONSTRUCTION OPTIONS (CONT.)
 Examples of construction options:

Lower control arm (1 piece, 2 piece (double ball joint), and
so on.)

Panhard rod

Hub compliance

Steering column U-joint phasing

Double cardon joint

nonlinear rack and pinion gear
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-12
CONSTRUCTION OPTIONS (CONT.)
 Hub Compliance

You use hub compliance in this workshop to model wheel
bearing play in the MSC.Adams model. Physical systems
will show compliance between the wheel and the hub parts
in the suspension. Adams/Chassis has four ways to account
for this compliance in your model:
●
Off - No compliance between wheel and hub
●
On - Additional compliance part added between wheel and
hub
●
Carrot_on - See online documentation
●
Carrot_off - See online documentation
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-13
CONSTRUCTION OPTIONS (CONT.)
 Hub Compliance (Cont.)

Below is a diagram of hub compliance on topology.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-14
CONSTRUCTION OPTIONS (CONT.)
 Hub Compliance (Cont.)



The parameters that affect the hub compliance model are:
●
Point 9 (wheel center) in hardpoint table
●
Optional point 9h (defined as offset along wheel spin axis in
construction option editor)
Note that bushing properties are defined in the connector
editor defining stiffness at ball joint
Point 9h has the effect of creating a moment arm between
loads applied to the wheel center and the bushing location.
The longer the offset, the more compliance there will be for
a given load and bushing property.
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-15
ADM761, Section 5, September 2012
Copyright 2012 MSC.Software Corporation
S5-16
SECTION 6
DETERMINING COMPONENT LOADS
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-1
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-2
DETERMINING COMPONENT LOADS
 What does this section contain?


Parts
Static Loadcase Event
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-3
PARTS
 Overview


Adams/Chassis includes a standard part list for every system.
Some subsystems have optional parts. The default center of gravity
(CG) option is to let Adams/Chassis geometrically place the CG.
The tabular format on the next slide shows rigid parts in subsystem,
mass, and CG location.
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-4
PARTS (CONT.)
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-5
PARTS (CONT.)
 Overview (Cont.)

You can open the part editor by selecting (double-clicking) the part.
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-6
PARTS (CONT.)
 Default CG option

The default CG option settings:
•
•

Place part CG at centroid of surface
defined by related hardpoints.
Set parametric - as hardpoints move, CG
also moves.
Note that the default option may not be as
accurate as defining the exact CG
location.
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-7
PARTS (CONT.)
 Inertial reference frame


Inertial reference frame (IM marker) is specified as principal
moments and cross products in the global reference frame.
Or, you can re-define the inertial reference frame by giving the
orientation and location.
 Graphics


You can control graphics parameters for links and control arms
(thickness, radius, and so on).
Optional external graphics are grouped under each part, specified
as .shl or .obj file from CAD system.
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-8
STATIC LOADCASE EVENT
 The static loadcase event is a half-vehicle event (front or rear)
that allows you to analyze vehicle characteristics that result from
loads that are placed at the wheel centers and at the tire
patches. It is used to calculate loads and deflections at every
connection in the model.
 Event Input

The event input is contained in XML format. Older versions of
Adams/Chassis that used the loadcase definition file (.lcd) are
automatically converted to XML if used. The input includes:
•
•
•
•
•
•
GVW (Gross Vehicle Weight)
FGAWR (Front Gross Axle Weight Rating)
RGAWR (Rear Gross Axle Weight Rating)
CG height
Wheelbase
Loading conditions in Gs (1 G is equal to GAWR)
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-9
STATIC LOADCASE EVENT (CONT.)
 Loading conditions

The loading conditions are divided into two types:
•
•

Body/Frame - Reports result in either global coordinate system only or
both global and part coordinate system
Component - Reports result in either part coordinate system or both
global and local
Loads can be applied in the following ways:
•
•
•
Vertical loads are applied at the wheel center, except for cornering
loads where loads are applied at the contact patch.
Longitudinal loads are applied at the wheel center, except for braking
loadcases where the loads are applied at the tire patch.
Lateral loads are applied at the tire patch.
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-10
STATIC LOADCASE EVENT (CONT.)

Load and displacement results are in report form:
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-11
ADM761, Section 6, September 2012
Copyright 2012 MSC.Software Corporation
S6-12
SECTION 7
EFFECT OF PASSENGERS ON FULLVEHICLE RESPONSE
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-1
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-2
DETERMINING COMPONENT LOADS
 What does this section contain?



Loading Subsystems
Static Vehicle Characteristics (SVC) Event
Frequency Response Event
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-3
LOADING SUBSYSTEMS
 Full-vehicle models require the following types of subsystems:







Body
Front suspension
Front wheel/tires
Steering column
Steering gear
Rear suspension
Rear wheel/tires
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-4
LOADING SUBSYSTEMS (CONT.)
 One example of an optional, full-vehicle subsystem is the
loading subsystem. It contains occupant and cargo loading
information, such as:

Occupant loading
•
•
•
•
•
•

Sets up passengers that can be toggled on and off in the model
Passengers are fixed to body part by default
Body subsystem contains a construction option to connect to the body
through spring damper and translational joint for ride analysis
You can easily switch passengers on or off using the occupant list
Inputs are mass and CG or H-point location
Adding passengers is simplified
Cargo modeling
•
•
•
•
•
Adds generic parts to your model
Connector is either fixed or bushing.
If using bushing, you must create hardpoints and bushings with an
identical name, and then add it to the connector list for cargo part.
Cargo may be attached to any part by specifying the part ID (for
example, body=51, frame=550).
Other inputs include mass, inertia, CG location, and optional graphics.
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-5
LOADING SUBSYSTEMS (CONT.)
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-6
STATIC VEHICLE CHARACTERISTICS (SVC)
EVENT
 An SVC event is a good place to start because it provides you
with basic vehicle-level information. It includes:

A snapshot of vehicle characteristics in current loaded condition
•
•
•
•



Sprung mass
Overall vehicle mass and inertia
Front suspension
Rear suspension
The ability to input desired output units
Output in report form, including important sign convention
information
Traditional first analysis for a full-vehicle model
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-7
STATIC VEHICLE CHARACTERISTICS (SVC)
EVENT (CONT.)
 The calculations are based on a compliance matrix, which is a
linear representation of a suspension at a particular ride height
and steer angle. Because vehicle suspensions are inherently
nonlinear, the characteristics computed by SVC are accurate
only at the ride height and steer angle for which they were
computed.
 For more information, see the Adams/Chassis online help.
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-8
STATIC VEHICLE CHARACTERISTICS (SVC)
EVENT (CONT.)
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-9
FREQUENCY RESPONSE EVENT
 A frequency response event is a full-vehicle analysis. It includes
a variety of steering methods to excite the frequency content of
the vehicle, such as:



Pulse
Swept sine
Time history
 The report processes time history and computes FFTs (Fast
Fourier Transform) in the frequency domain.
 The goal of a frequency response test is to provide steering
input that spans the entire frequency range of a human driver,
roughly 0 to 3 Hz.
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-10
FREQUENCY RESPONSE EVENT (CONT.)
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-11
ADM761, Section 7, September 2012
Copyright 2012 MSC.Software Corporation
S7-12
SECTION 8
TIRE MODELING
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-1
TIRE MODELING
 What does this section contain?



Tire/Wheel Setup
Tire Modeling
Constant Radius Analysis
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-2
TIRE/WHEEL SETUP
 Tire/Wheel setup utility


Found in the suspension subsystem editor.
Different from the alignment options as it orients the tire during
design configuration, not after a static simulation.
• An axis that a tire/wheel rotates about is defined by two points:
wheel center (pt 9) and the spindle alignment point (pt 11). If you
change the camber and toe of the tire in Adams/ Chassis, it
simply changes the relative location of the spindle alignment
point to the wheel center, which changes the orientation of the
spin axis.
• Note that this does not change other parameters such as lower
or upper ball joint locations.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-3
TIRE/WHEEL SETUP (CONT.)

In the set up utility:




Spindle align vector length (distance between pt 9 and pt 11 along
spin axis)
Toe
Camber
Loaded tire radius
 Spindle alignment point (pt 11) and tire patch (pt 10) are
calculated based on these parameters, along with the wheel
center hardpoint location. Select Apply to paste the current
values to the hardpoint table.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-4
TIRE/WHEEL SETUP (CONT.)
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-5
TIRE MODELING
 Several tire models are available since tires have a large effect
on vehicle handling.
 Example files are stored in <examples>/tir. You can find
information on the types of tire models in the Adams/Tire
documentation.
 Adams/Tire calculates the equivalent forces and moments on
the spindle due to tire/road interaction.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-6
TIRE MODELING (CONT.)
 Three types of tire modules:

Adams/Tire Handling module - Incorporates the following tire
models for use in vehicle dynamic studies:
• Fiala tire model (least advanced, no camber effects)
• Pacejka’89 and Pacejka’94 models
• Pacejka 2002 (also known as PAC2002), replaces version 2003 and
older MF-Tyre (Delft-Tyre) from TNO
• UA-Tire model includes relaxation effects, both in longitudinal and
lateral direction
• 5.2.1 Tire model, the original Adams/Tire model, offers two methods
calculating slip forces and moments and two contact models
• Adams/Tire Handling uses a point-follower method to calculate tire
normal force and is limited to 2-D roads.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-7
TIRE MODELING (CONT.)
 Three types of tire modules (Cont.):

Adams/Tire 3D Contact module
• Uses a 3D equivalent-volume method to calculate tire normal force on
three-dimensional roads for use in predicting vehicle loads for durability
studies.
• When you purchase Adams/Tire and Adams/Tire 3D Contact module
separately, you can only use the Fiala model to calculate tire handling
forces and moments.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-8
TIRE MODELING (CONT.)
 Three types of tire modules (Cont.):

Adams/Tire FTire module - The FTire module is the latest addition
to Adams/Tire. It is a new tire model for durability and ride and
handling applications that:
• Offers an effective compromise between model fidelity and detail, and
computational speed.
• Provides valid results up to 120 Hz in the frequency domain.
• Lets you easily derive model parameters from tire measurement data.
• Provides valid results for short obstacles with wavelengths down to half
the size of the tire-road contact patch.
• For more information, see http://www.ftire.com.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-9
CONSTANT RADIUS ANALYSIS


Constant radius analysis analyzes:
●
The model in a steady-state cornering condition
●
The behavior of the vehicle in constant radius turn at different
lateral acceleration levels
Report metrics such as:
●
Understeer gradient
●
Roll gradient
●
Understeer budget
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-10
CONSTANT RADIUS ANALYSIS (CONT.)
 Understeer budget


You will use understeer budget in this workshop.
Understeer budget lists contributions to understeer gradient
from different sources. The Adams/Chassis online help
contains detailed calculations used to determine understeer
budget.
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-11
ADM761, Section 8, September 2012
Copyright 2012 MSC.Software Corporation
S8-12
SECTION 9
INSTRUMENTING THE MODEL
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-1
INSTRUMENTING THE MODEL
 What does this section contain?



Instrumentation Subsystems
Two-part Body Construction Option
Swept Steer Full-Vehicle Event
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-2
INSTRUMENTATION SUBSYSTEM
 The instrumentation subsystem is an optional subsystem
available for full-vehicle models. This subsystem contains
various tools used in virtual-to-physical model correlation
studies.
 The types of instrumentation are:

Ride height sensors
• Return the distance between location and ground plane.
• You specify the part ID and XYZ coordinate of location.
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-3
INSTRUMENTATION SUBSYSTEMS (CONT.)

Ride height sensors (cont.)
• Request 51061 returns the distance between the height sensor and the
ground in the ground's reference frame (shortest distance).
• Request 51062 returns the distance between the height sensor and the
ground in the height sensor's reference frame (distance as laser-based
sensor would read).
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-4
INSTRUMENTATION SUBSYSTEMS (CONT.)
 The types of instrumentation are (Cont.):

Stringpots
• Transducers that measure the displacement between two positions in
your vehicle system.
• You specify the part ID and XYZ coordinate of the two ends of the
stringpot.
• Wheel deflection stringpots are unique; they are activated by using a
specific name (for example, lf_wheel_deflection).
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-5
INSTRUMENTATION SUBSYSTEMS (CONT.)
 The types of instrumentation are (Cont.):

Velocity sensors
• Measure lateral and longitudinal velocity of the vehicle through Q-head
transducers.
• You specify front and rear XYZ sensor placement.
• They are used to correlate sideslip measurements.

Acceleration sensors
• Acceleration sensors measure body lateral and longitudinal acceleration.
• You specify the part ID and XYZ coordinate of the sensor.
• Subsystem construction option sets which calculation method is used.
– Corrected - Acceleration in body reference frame.
– Uncorrected - Acceleration as accelerometer would measure. Contains additional
component roughly equal to sin(pitch or roll angle)*gravity
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-6
TWO-PART BODY CONSTRUCTION OPTION
 Two-part body construction option:


Enhances the model by allowing compliance between the front and
rear suspension subsystems.
Found in the body subsystem.
 The two flexibility models available are:



Torsion - One DOF about X-axis between front and rear body parts;
revolute joint connects two halves.
Torsion and Bending - Two DOF about X and Z axes; universal
joint connects two halves.
Torsion, Lateral and Vertical Bending - Three DOF about X, Y and
Z axes
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-7
TWO-PART BODY CONSTRUCTION OPTION
(CONT.)
 You specify the torsional and optional bending stiffness for the
linear bushing placed at the connector. The joint and bushing
are placed at the original body CG location.
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-8
TWO-PART BODY CONSTRUCTION OPTION
(CONT.)
 Each body part has half of the original body mass. The mass
and inertia properties are automatically determined so that the
aggregate properties of the two halves are exactly the same as
the rigid body part specification.
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-9
SWEPT STEER FULL-VEHICLE EVENT
 A swept steer full-vehicle event tests a vehicle's directional
control response characteristics under quasi-steady stateturning conditions. In this way, it is very similar to a constantvelocity cornering event.
 You specify:



Vehicle speed
Final lateral acceleration
Left or right turn direction
 Steering wheel input is applied at a slow enough rate so that no
transient effects of response lag are evident.
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-10
SWEPT STEER FULL-VEHICLE EVENT
(CONT.)
 Steering wheel input is applied at a slow enough rate
so that no transient effects of response lag are
evident.
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-11
ADM761, Section 9 September 2012
Copyright 2012 MSC.Software Corporation
S9-12
SECTION 10
USING OPTIONAL SYSTEMS
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-1
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-2
INSTRUMENTING THE MODEL
 What does this section contain?






Brake subsystem
Powertrain Subsystem
Controls Subsystem
Additional Rear Suspensions
Open-Loop Braking Event
Straight-Line Deceleration Event
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-3
BRAKE SUBSYSTEM
 You have now used two types of full-vehicle optional
subsystems: loading and instrumentation. There are four other
types of optional subsystems:




Brakes
Powertrain
Controls
Additional rear suspensions
 Brakes

Simple braking events, such as straight-line deceleration, require a
very simple brake subsystem. The straight line deceleration event
has the following characteristics:
•
•
•
There is one parameter in a spline that defines the front-rear brake
proportion as a function of deceleration.
There are four torques that are applied to each wheel.
The built-in controller applies torque that is necessary to achieve
desired deceleration.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-4
BRAKE SUBSYSTEM (CONT.)
 Other full-vehicle events, such as open-loop braking, require an
enhanced model with the following characteristics:



The controller applies force to the brake pedal instead of a torque
on each wheel.
The torque on each wheel is calculated based on the brake model
and pedal force.
The parameters include:
•
•
•
•
•
Pedal-lever force ratio
Master cylinder and brake piston diameter
Hydraulic efficiencies
Brake factor (captures pad/rotor friction coefficient)
Bi-linear or spline definition for vacuum booster and proportioning valve
gains
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-5
BRAKE SUBSYSTEM (CONT.)
 Characteristics (Cont.):

The two methods of pad location:
•
•

Radius - The distance from the wheel center to pad center, that is
multiplied by the friction force to determine braking torque.
XYZ location (the pad center location) - The force applied tangent to
the line between the wheel center and the XYZ point and in the XZ
plane.
There are no compliance or inertial effects included in a complex
Adams/Chassis brake model.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-6
BRAKE SUBSYSTEM (CONT.)
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-7
POWERTRAIN SUBSYSTEM



Similar to the brake subsystem, there is a simple and complex
powertrain model.
The simple powertrain model uses a built-in traction controller to
apply torques directly to the wheels. This is used for
acceleration controlled events.
Simple powertrain input parameters
– The input parameters include:
o Controller proportional gain
o Controller integral gain
o Front drive torque ratio defined in the system file and is the proportion
of the drive torque applied through the front wheels (for example,
FWD=1.0, RWD=0.0)
– The complex powertrain model requires more parameters, but
results in an analysis of engine and differential mounting, drivetrain
loads, and other details.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-8
POWERTRAIN SUBSYSTEM (CONT.)

Complex powertrain input parameters
– The parameters include:
o System hardpoint locations
o Part information
o Connector properties
o Torque versus RPM engine map splines for various throttle positions
o Construction options - include powertrain model type, engine mount
part, number of engine mounts, viscous coupling, and so on.
o Parameters - include half-shaft dimensions (for torque steer analysis),
gear ratios, controller integral and proportional gains, and so on.

See the following page for a schematic AWD powertrain.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-9
POWERTRAIN SUBSYSTEM (CONT.)
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-10
POWERTRAIN SUBSYSTEM (CONT.)

Adams/Driveline to Adams/Chassis
– You can create your powertrain system in Adams/Driveline and
export it to Adams/Chassis.
o Use the Export Adams/Driveline Model to Adams/Chassis feature
available in the Adams/Driveline Tools menu. This creates an XML file
that Adams/Chassis can read.
o Reference the exported Adams/Driveline XML subsystem in
Adams/Chassis in the Powertrain option of the vehicle system file.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-11
CONTROLS SUBSYSTEM

Example applications
– Anti-lock braking system
– Active yaw control
– Engine cruise control
– Electric Power Assisted Steering (EPAS)

You can either import an MSC.Easy5 or MATLAB control
system, or you can use FORTRAN or C source code.
Adams/Chassis helps set up the control system inputs and
outputs. There is a predefined list of inputs and outputs and you
can add additional inputs or outputs.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-12
CONTROLS SUBSYSTEM (CONT.)

Example inputs
– Master cylinder pressure
●
Engine speed
– Steering wheel angle
●
Ride height
– Steering wheel velocity
●
Torsion bar torque
– Wheel speed (4)
●
Time
– Vehicle speed
●
Rack travel
– Accelerometer signals
●
Rack velocity
– Yaw rate
– Throttle position
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-13
CONTROLS SUBSYSTEM (CONT.)


Example outputs
– Brake line pressure (4)
●
Steering boost torque/force
– Brake torque (4)
●
Engine torque
– Damper settings (4)
●
Transmission gear ratio
The guide, Getting Started Using Adams/Chassis, contains a tutorial
for using an ABS control system with a complex braking system.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-14
ADDITIONAL REAR SUSPENSIONS

You can include up to three additional rear suspensions in your
model. Each suspension requires a suspension subsystem and
a wheel and tire subsystem. Applications include:
– Trailers
– Heavy trucks with more than one rear axle

Types of trailer models
– There are three types of trailer models available in the example
vehicle database: a simple model and two variations of a complex
model.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-15
ADDITIONAL REAR SUSPENSIONS (CONT.)

Types of trailer models (Cont.)
– The diagram below illustrates the simple model in the example
database, truck_trailer.vdb.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-16
ADDITIONAL REAR SUSPENSIONS (CONT.)

Complex trailer model
– The complex trailer
model is in the example
database, trailer.vdb. It
includes load leveling
ability.
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-17
STRAIGHT LINE DECELERATION EVENT

This event is a closed-loop analysis. The input to the controller
is the vehicle's acceleration and the output is the brake torque
level.
– Input:
o Initial vehicle velocity
o Final deceleration level
o Number of output steps
– Plots (as functions of longitudinal deceleration):
o Pitch angle
o Lift/dive
o Tire forces
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-18
OPEN-LOOP BRAKING EVENT

The open-loop braking event includes the following:
– Input:
o Step or spline (pedal force versus time) brake input
o Initial vehicle velocity
– Plots (as functions of time):
o Pedal force
o Vehicle position and acceleration
o Tire slip ratios
o Vertical tire force
o Brake torque
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-19
ADM761, Section 10, September 2012
Copyright 2012 MSC.Software Corporation
S10-20
SECTION 11
INTEGRATION WITH Adams/INSIGHT
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-1
INTEGRATION WITH Adams/INSIGHT
 What does this section contain?





What is Adams/Insight?
Recent Design Advances
DOE Theory and Response
Creating User Responses in Adams/Chassis
Adams/Chassis Improve Mode
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-2
WHAT IS Adams INSIGHT?
 Adams/Insight is a stand-alone product that also works with
Adams/View, Adams/Car, Adams/Engine, and Adams/Chassis.
Adams/Insight lets you design sophisticated experiments for
measuring the performance of your mechanical system. It also
provides a collection of statistical tools for analyzing the results
of your experiments so that you can better understand how to
refine and improve your system. The diagram on the next slide
shows how Adams/Insight relates to other MSC.Adams
products.
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-3
WHAT IS Adams INSIGHT?
 MSC.Adams products encompass the solution


The base is Adams/Solver, required for solving equations of motion
of mechanical system. Custom components are incorporated for
elements such as tires and flexible bodies.
On top of Adams/Solver is Adams/View, the parametric engine to
create Adams/Solver models. Customized Adams/View products
enable analysis of common machine groups, such as automobiles.
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-4
WHAT IS Adams INSIGHT? (CONT.)
 Adams/Insight drives the parametric engines intelligently, helps
interpret results, and simplifies sharing information.
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-5
RECENT DESIGN ADVANCES
 Virtual Prototyping
 Parametrics
 Collaboration
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-6
RECENT DESIGN ADVANCES (CONT.)
 Virtual Prototyping (70s - 80s)



ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
Focus on developing ONE model of
ONE design.
Evaluation of design changes required
modeling expertise; could be time
consuming.
Evaluation of design change was errorprone.
S11-7
RECENT DESIGN ADVANCES (CONT.)
 Parametric Modeling (90s)





ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
Preprocessor developed for specific
mechanical systems.
Analysts maintained model parameters.
Standard modeling practices leveraged
throughout organization.
Attribute specialists no longer needed to
be MSC.Adams experts to get job done.
Faster A/B comparisons.
S11-8
RECENT DESIGN ADVANCES (CONT.)
 Collaboration (present)



ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
Analyst quickly evaluates design space.
Analyst quickly communicates to
organization.
Analyst enables collaboration within
organization.
S11-9
DOE THEORY AND RESPONSE SURFACES
 DOEs for design space exploration

Minimize the number of design
evaluations using DOE theory to
discretize the design space
intelligently.
 Response surfaces for interpretation

Fit results of trial evaluations by
assuming design surface continuity,
and gain the ability to rapidly predict
performance of any model within the
design space.
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-10
CREATING USER RESPONSES IN
Adams/CHASSIS
 In addition to the standard library of responses based on
Adams/Chassis reports, Adams/Insight provides some general
utilities to create custom responses for processing MSC.Adams
request data.
 User response naming convention


Adams/Insight requires a strict naming convention for user
responses added to Adams/Insight experiments with
Adams/Chassis.
Each event included in the experiment has a prefix, which appears
in the response hierarchy in Adams/Insight.
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-11
CREATING USER RESPONSES IN
Adams/CHASSIS (CONT.)
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-12
CREATING USER RESPONSES IN
Adams/CHASSIS (CONT.)
 User response naming convention (Cont.)



When adding user responses, you must begin the name of your
response with the prefix corresponding to the event with which the
response is associated.
For example, in the image on the previous page, the following user
response names are valid:
Valid user response names:
• e_001_achassis_gs_full_sys_swep_1_max_latacc
• e_002_achassis_gs_full_sys_ride_2_average_left_toe
• e_003_achassis_gs_full_sys_scomp_3_left_toe_at_6_seconds

Invalid user response names:
• max_latacc
• average_left_toe
• left_toe_at_6_seconds
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-13
CREATING USER RESPONSES IN
Adams/CHASSIS (CONT.)
 Single request user responses


This first kind of user response processes the time history of a single
MSC.Adams request. The following types are available:
To create an Adams/Insight response for one of these, you must
create a new response. Select the User Response Type button, and
enter a string with the following syntax in the Variable text box:
• plts:<type>:req_<id>:<col_number>[:time_range:<tmin>:<tmax>]
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-14
CREATING USER RESPONSES IN
Adams/CHASSIS (CONT.)

In the example shown on the previous page, the following are
required arguments:
– type - One of the types listed above (max, min, and so on.)
– id - Numerical MSC.Adams request ID
– col_number - MSC.Adams request column number (1-6)

The following is the optional time range feature where you must
specify the minimum and maximum time:
– tmin - Minimum time for output
– tmax - Maximum time for output
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-15
Adams/CHASSIS IMPROVE MODE
 The Improve mode in Adams/Chassis creates a gateway for you to
use the features of Adams/Insight.
 Investigations

In the Improve mode, you create investigations to efficiently vary
system parameters and monitor how these changes effect system
performance. You select systems (events) that you want to
investigate. An investigation enables you to learn more about a system
and then efficiently communicate this enhanced understanding with
the rest of the design community.
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-16
Adams/CHASSIS IMPROVE MODE


The results of these investigations are then presented to you using
Adams/Insight. Once in Adams/Insight, you can specify the subset of
factors and responses that are identified as Inclusion Factors or
Inclusion Responses. Adams/Insight then allows you to create a
workspace or a grid of Trials identifying how each factor will be set for
each trial.
The Improve mode allows you to:
• Setup an investigation
• Execute an investigation
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-17
ADM761, Section 11, September 2012
Copyright 2012 MSC.Software Corporation
S11-18
SECTION 12
INTRODUCTION TO CUSTOMIZATION
WITH Adams/CHASSIS
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-1
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-2
INTRODUCTION TO CUSTOMIZATION WITH
Adams/CHASSIS
 What does this section contain?

Adams/Chassis Pre-Processing Flow

Adams/Chassis Modeling Customization

Adams/Chassis Event Customization

Adams/Chassis Plotting Customization

Custom Adams/Solver Library
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-3
Adams/CHASSIS PRE-PROCESSING FLOW
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-4
Adams/CHASSIS PRE-PROCESSING FLOW
(CONT.)
 What is Python?


An interpreted, interactive, and object-oriented programming
language.
Often compared to Tcl, Perl, Scheme or Java.
 Python and Adams/Chassis


Python is used after Adams/Chassis version 12.0
Previous versions of Adams/Chassis used a custom program called
AFM (ASCII File Manipulator) to build MSC.Adams input files. AFM
is a process-oriented language (like FORTRAN).
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-5
Adams/CHASSIS PRE-PROCESSING FLOW
(CONT.)
 Python and Adams/Chassis (Cont.)


In version 12.0, AFM (procedural) files were translated into Python.
In version 2003, event building files take advantage of Python
object-oriented classes.
Advantages of Python:
• Open source
• Free to use
• Others develop and maintain it instead of in-house
• Extensive third-party support network (for example, www.python.org)
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-6
Adams/CHASSIS MODELING CUSTOMIZATION
 The Adams/Solver input files generated with Adams/Chassis are
created by referencing a series of Python (.py) files. These files
can be thought of as formatted text with “blanks”, where the
“blanks” are filled in with functions of the vehicle data from the
system, subsystem, and property .xml files.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-7
Adams/CHASSIS MODELING CUSTOMIZATION
(CONT.)
 The template files are stored in <achassis_top>/pre_py
 The last section of every .adm file details the .py files in the
order that was used to build the model.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-8
Adams/CHASSIS MODELING CUSTOMIZATION
(CONT.)
 If you look at the sample on the previous page, Nest is the
sequence of .py calls. (01) nested files are called from (00)
nested files, (02) files are called from (01) files, and so on.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-9
Adams/CHASSIS MODELING CUSTOMIZATION
(CONT.)
 Therefore, you can basically step through the creation of the
Adams/Solver input files. If you identify a need to customize a
step in the process, you:



Copy the .py file to customize to your working directory
Edit your local copy of the .py file to incorporate your custom
Python code
Select Use personal files when building your model
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-10
Adams/CHASSIS EVENT CUSTOMIZATION
 You can use custom full- or half-vehicle events if you want to
modify an existing event or create a new one.
 You typically start the process by copying an example event
definition file from <achassis_top>/pre_py/events to your
working directory.
 Remember that the Adams/Chassis Preferences window
contains a section to specify where custom event files are found
 You can specify the input values, strings, and/or radio buttons to
control the event.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-11
Adams/CHASSIS EVENT CUSTOMIZATION
(CONT.)
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-12
Adams/CHASSIS EVENT CUSTOMIZATION
(CONT.)
 After creating the custom event, you select Reload Custom
Events under the Edit menu to load the custom event in the
treeview.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-13
Adams/CHASSIS PLOTTING CUSTOMIZATION
 The default plotting process is:


The plotting templates still use .aft files that use the AFM program.
This will be updated to Python in the future.
All standard plots are created using .aft files from
<achassis_top>/post/plot/SI or <achassis_top>/post/plot/English,
depending on the unit setting in the preferences.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-14
Adams/CHASSIS PLOTTING CUSTOMIZATION
(CONT.)
 The procedure to customize plotting is similar to event
customization:



Copy default .aft file for an event from <achassis_top>/post/plot/SI
or /English to your working directory.
Make necessary changes to the .aft file.
Select Use personal files in the PostProcessing window to use the
custom .aft file instead of the default.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-15
CUSTOM Adams/SOLVER LIBRARY
 Adams/Chassis uses a customized Adams/Solver library when
simulating events. You can include custom Fortran or C++
subroutines and link them in with the default Adams/Chassis
subroutines and Adams/Solver code.
 The process is centered on the use of the Adams/Chassis
buildcust option:
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-16
CUSTOM Adams/SOLVER LIBRARY (CONT.)
 Once the custom Adams/Chassis Adams/Solver library is
created, you can change the Solver command on the
Preferences page:
 Using custom user subroutines is covered in the Advanced
Adams/Solver course.
 Customizing Adams/Chassis methods, events, plots, reports,
and libraries is covered in further detail in the Customization
with Adams/Chassis course.
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-17
ADM761, Section 12, September 2012
Copyright 2012 MSC.Software Corporation
S12-18
SECTION 13
ADAMS/CHASSIS FLEX BODY
INTEGRATION IMPROVEMENTS
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-1
ADAMS/CHASSIS FLEX BODY INTEGRATION
IMPROVEMENTS
 What does this section contain?

Adams/Chassis Flex Body Integration Improvements

Adams/Chassis Flex Body Generation event

Adams/Chassis Flexible Parts editor
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-2
Adams/Chassis Flex Body Integration
Improvements

From A/Chassis 2012 release flexible body modeling has been
expanded to support any part in the subsystem.

Flex body generation utility is provided to provide automatic generation
of flexible part property files(.py) based on a user-provided modal
neutral file (MNF).

It provides GUI access for flex body utilities, node mapping, and
automates the process of mapping flex body node IDs to Chassis hard
point IDs. The number of files you have to manage when modeling flex
bodies has been reduced. Overall, integrating flex bodies into your
Adams/Chassis model is a more efficient process.
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-3
Adams/Chassis Flex Body Generation Utility

The new Flex Generation event simplifies the modeling of flexible
bodies in the Adams/Chassis model. Instead of requiring users to
manually generate the mapping between the Adams/Chassis
hardpoints and the flexible body node IDs, the utility will do all of this
automatically.

Users need only to create the modal neutral file, and the utility will
create the flexible body property file for inclusion in the Adams/Chassis
model.
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-4
Adams/Chassis Flex Body Generation Utility

The Flex Body Generation Utility aids in the construction of the flexible
part property file (.py) by automatically determining the closest
attachment nodes for each hardpoint in the selected flexible part
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-5
Adams/Chassis Flex Body Generation Utility

The flex body generation utility (event) provides for automation of the
flexible part property file (.py) in Adams/Chassis. The utility requires the
following inputs:

Part Name/Number



Modal Neutral File (.mnf)
The utility has the following outputs:

Flxpre setup file (.dat)

Flex mapping file (.flx)

Adams/Solver matrix file (.mtx)

Adams/Chassis flexible part property file (.py)
The utility is accessed via the test mode bookshelf:

Full Vehicle > Utilities > Flex Body Generation
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-6
Adams/Chassis Flexible Parts editor

The Adams/Chassis Flexible Part editor has been expanded to allow
the modification of flex body properties directly from the Build mode.

This eliminates the need to create mulitiple flex body property files or to
use custom_adm text to simply change a property of the Flex Body
statement.

The following properties are now supported for modification:

Flex body origin

Damping (function or constant)

Inertial coupling

Dynamic limit [C++ Solver only]

Stability factor [C++ Solver only]
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-7
Adams/Chassis Flexible Parts editor

Flex Origin

Defines the Cartesian initial coordinates of the BCS with respect to
the ground coordinate system. Defaults to (0,0,0).

Dynamic Limit


Specifies the dynamic limit frequency of this flexible body in Hertz
[C++ Solver]
Stability Factor

Specifies the stability factor for quasi-static modes when the
dynamic limit feature is enabled on this flexible body [C++ Solver]
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-8
Adams/Chassis Flexible Parts editor

Flex Damping (CRATIO):
•
Default Damping (default): Use Adams/Solver default
•
User-defined Damping: Applies the following user-defined damping
ratios:

Initial Damping Ratio to modes under Frequency #1

Damping Ratio #2 to modes between Frequency #1 and Frequency
#2

Final Damping Ratio to modes greater than Frequency #2

Damping Function: User can enter any value or function in this field
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-9
Adams/Chassis Flexible Parts editor

Flex Inertial Coupling (INVARIANTS):
Specifies a true and false pattern indicating which of the nine inertia
invariants Adams/Solver should use to model inertia coupling of the
flexible and rigid body motion

Rigid: Disable all deformations



Constant: Neglect all deformation corrections to the mass matrix
Partial (default): Ignore second-order deformation corrections to the
inertia tensor, and the first-order corrections to the rotational and
flexible inertia coupling
Full: Full inertia coupling of deformation and rigid body motion
ADM761, Section 13, September 2012
Copyright 2012 MSC.Software Corporation
S13-10
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