7.Adams Car Level 02

7/22/2019 7.Adams Car Level 02

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Monish Gowda M.H.

MSRSAS Ban alore

M S Ramaiah School of Advanced Studies -

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Level-02 Session Objectives

Create and modify templates

Learn how to create new requests within the same subsystem

as we as e ween eren su sys ems

Create and modify different property files Create and modify automotive elements such as spring,

dampers, bushings

Setup suspension simulations

Perform sus ension simulations


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User Modes in ADAMS/Car

Within the ADAMS/Car configuration file (*.acar.cfg), the

standard user mode and expert user mode

Standard user ( Standard Interface only )

S ecificall for desi ners and testin en ineers

Use libraries from the ADAMS/Car database to easily

Simulation environment tailored to automotive standards


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Expert user ( Template Builder and Standard Interface)

Allows creation of building-block of ADAMS/Car, templates,

with access to

emp ate u er

For experienced ADAMS users

Difference between templates and subsystems

A template is the base-level MSC.ADAMS model that defines the

, , , ,

make up a specific area of the vehicle, such as a front suspension.


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An ADAMS/Car subsystem is based on an ADAMS/Car template

, ,hardpoints, parameters, and other items

Overall, a template defines the structure/topology of a model, and

a subsystem redefines whatever parameters the user wants tocreate an instance of the template for analysis


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Database Structure A database is a collection of directories stored on the hard drive

, . ,

number of directories

Each directory is a placeholder for model information

Three types of database are

Shared - Common to all users, provided by MDI with

example files (C:\Program Files\MSC.ADAMS 2003\acar\shared_car_database.cdb)

Private - User workspace (created by ADAMS/Car inyour HOME directory) (C:\Documents and Settings\user\private.cdb)


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Major and Minor Roles ADAMS/Car uses major and minor roles to create assembly

within the assembly

very emp a e as a e ne ma or ro e suc as suspens on,

steering wheel etc., When a subsystem is created the standard user defines the

subsystemminor role as front, rear, trailer or any

This enables the same suspension template to be used for both

front and rear


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Modeling As per the hierarchy any kind of modeling in ADAMS/Car has

o s ar w emp a e u er mo e

ADAMS/Car has inbuilt default templates for most of the

subsystems

These templates are used and there hard-points are changed to

suit the vehicle of our choice


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Create a full vehicle AssemblyTo assemble a car using templates:

nter temp ate u er mo e

Open the required template and make modifications

according to requirement

Save the template (*.tpl) file in private data base

Switch back to normal mode

Create new subs stem usin the above saved tem late file

Save subsystem (*.sub) file in private data base


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Template building

This is to be done in template builder mode

Re uired tem late file *.t l should be o ened and modif

according to requirement

Save the file

Subsystem building

This is to be done in normal mode

Here the user can create new subsystems using the saved

template


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Minor role should be defined here


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AssemblyThis also should be done in normal mode

subsystems


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Template Building Template building can only be done in the template builder

mode. This o tion ma not be activated in our machine. To

do so browse to

. .

Open the file.acar.cfgin notepad and change the user mode to

expert instead of standard

To open in template building mode, while starting Adams/Car

will ask for this option or can toggle using Tools Adams/Car

template builder or press F9


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Expertmode

Templatebuilder


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Template Building process

While in template builder mode open required template file and edit it


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*.tpl files are not Ascii files and cannot be opened in notepad But you can save it as Ascii file and edit properties

Save the file in private database

or shared databaseThe template is saved in a database created for the

particular vehicle with major role as brake_system


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and the file format being Ascii


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Macpherson strut template for suspension system


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Press V to toggle icon visibility


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To change the hardpoints

Using the hard point data of chosen vehicle

the template is to be modified to suit the

Change hardpoints and save the template


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Changing different parameters will be discussed in later sessions

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Subsystem Building process

Once the template is saved, switch to normal mode


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Point to New subsystem to create a new subsystem


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Subsystem opened


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Assigning Mass and Inertia


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Save Subsystem Minor role has to be chosen properlyw e ca ng n emp a es an sav ngsubsystems

In case of suspension system minor rolecan be either front or rear depends on

e ve c e c osen


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Same procedure should be adopted to create other subsystems


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Brake Subsystem


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TR_Brake_System.sub

Kinematic_flag : This is used to toggle between kinematic and

com liance mode. 0 = Kinematic & 1= Com liance

Front_brake_mu: This is the frictional coefficient of brake pad

_ _ _ - -

piston-radius parameter, (length). This define the radius of piston

Front_p ston_area : T s s t e p ston-area parameter,

(length**2). This define the cross sectional area of the piston.

The difference between effective piston radius and piston area is

that the above term is used to define radius (length) and this term


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is used to define area of the piston


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_ _ _ _wheel by x mm

_ _ _ .

Front_rotor_width : This is negative because to

define/reflect width on negative side of Y axis

Max_brake_value : Heree you should use value of the pedalforce, and unit is depends on the units of the model


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Subsystems required to create a full vehicle assembly

Front Suspension Subsystem

Rear Suspens on Su system

Steering Subsystem

Front Wheel Subsystem

Rear Wheel Subsystem Body Subsystem

Brake Subsystem

Power Train Subsystem

Other Subsystem (If any)


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Creation of Full Vehicle Assembly

Once all the subsystems have been created in the same way

and saved into the new car database, they are ready to be

called into an assembly

ADAMS/Car is started in the standard mode and from file

menu new full vehicle assembl is selected

The different subsystems which were saved in the new

.

in the database


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Brakes and Powertrain subsystems are in OFF condition by

default

For acceleration and brakin anal sis these two s stems should

be selected and their respective subsystems must be called from


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Vehicle Test Rig by default is MDI_SDI_Testrig

I lu ins like Ride and Chassis are switched on in the lu in mana er


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additional test rigs such as 4post testrig and the Driver testrig would be

available to be selected

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Assembled Car


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Assembled Car


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Further analysis can be carried out using this vehicle

Once these tests are conducted, graphs have to be plotted and compared

against standard graphs available in literature

If the trends of the two are matching then it can be concluded that the

validation was successful and the model assembled can be used for further

experimentation


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Velocity Time graph


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Editing various parameters of vehicle

Adjust Hardpoints

assembly mode on either a suspension or a full-vehicle assembly From the Ad ust menu oint to Hard oint and then select either

Modify or Table

It is recommend that you select Table because it lets you adjustseveral hardpoints at once

Make Plots with Data Other than Time

From the Review menu, select Postprocessing Window


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Independent Axis to Data.

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Set Toe, Camber, and Other Parameters

rom e us menu, po n o arame er ar a e, an en se ec

either Modify or Table

you want to modify

,

Select OK.

Change the Tires

Tires can be changed by right-clicking the wheel part and

choosing Modify

Then set Tire File to the name of the file you want to use

You can alter a tires properties, such as radius and vertical


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stiffness, by modifying the property file in a text editor

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Modify Springs or Dampers

Right-click on the spring or damper, and then select Modify

You can edit the curve by dragging on the plot, or by changing

values in the data table

You can modify springs or dampers when working in either

subsystem or assembly mode on either a suspension or a full-

vehicle assembly

ar stores spr ng an amper ata n a property e n

the ADAMS/Car database directory structure

Modify Trackwidth

You can only modify trackwidth by changing the lateral (y)


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coordinate of the relevant suspension hardpoints

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Modify Wheelbase and Vertical Position

Make sure that you have a suspension or full-vehicle assembly

open

From the Adjust menu, select Shift

Set Subsystem to the name of the subsystem you want to move

Specify a vertical and a fore/aft distance to move the subsystem

Changing Steering Ratio

Make sure that you have a gear in your assembly or subsystem

From the Adjust menu, select Gears

In the Gear Name text box, select the gear you want modify In the Reduction Ratio text box, specify the desired ratio.

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a e sure to c ange t s, as t e e au t va ue s .

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Set Powertrain Data

rom t e ust menu, po nt to arameter ar a e, an t en

select either Modify or Table

e u sys em o e name o e power ra n su sys em w ose

parameters you want to modify

, , ,

engine speed parameters, and so on

To control lower arm thickness

Ri ht-click either lower control arm the red trian ular area

Point to Arm: graarm_lower_control_arm, and then select Modify

Change the Thickness


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Select OK

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Creating new requests ( measures )

o create new requests, n emp ate u er, go to u

RequestsNew

ou can on y crea e reques s n emp a e u er mo e

The results set names appears in the Request list in


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Adding CAD Graphics to Template

oa t e c ass s temp ate n to ar


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Ordinarily, you could right mouse click and delete the body graphic, or you

could select "Delete" rom the File menu. Don't use these

From the Tools menu, start the Command Navigator and find the "geometrydelete" command


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Import body graphic

s s own e ow, c oose one o t e e ormats supporte y , suc asParasolid, IGES, stl, slp, obj, etc.


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Each file format may have slightly different information required

or options provided items like scaling, reference marker,

, ,

If you need to specify a reference marker, use the "shell_rm"

mar er

Then, if necessary, move or rotate the "shell_rm" marker to fine-

tune the position of your frame/body graphics

It is critical to specify the ges_chassis part as the part to which

your geometry will belong (when given the choice, specify

" art" and not "model" .


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Finished Product !!!


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Conclusion

Discussed in detail how to

Create and modify templates and different parts

Create and modify different property files

Create and modify automotive elements such as spring,

dampers, bushings


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