Suspension and Chassis Loads using - Altair University and Chassis Loads using Michael White ......

Suspension and Chassis Loadsusing

Michael White

Product Manager-Durability Director

Presenter:

Copyright © 2009 Altair ProductDesign, Inc. All rights reserved. 2

Agenda

� Loads Extraction Using Hyperworks

� Introduction

� Loading Methodology

� Building & Running Multibody Models

� Post Processing and Checking the Loads

� Applying Loads to a Finite Element Model

� Summary


Loads Extraction Using Hyperworks


Agenda


� Introduction





� Summary


Introduction To Vehicle Loads

-Exact Loads are not known in the design phase

-Past History Can be used to estimate New loads

-You need to verify the loads using some method:-Load measurement using transducers (best)-Strain measurements-Inspection after shakedown and during events (worst)



Concept of “G” loading

-Choose a load condition to design to (“Design load”)-Vehicle sitting on the ground at design load is at 1 “G”-Load on a vehicle is proportional to the vehicle weight

*ignores tire and use case effects


Agenda


� Introduction





� Summary



“G” Load Application

-Calculate Loads in all directions using the “G” concepti.e.-1 G Vertical Load-2 G Vertical Load-3 G Vertical Load-1 G Braking-1 G Lateral-2 G Vertical plus 1 G braking




-What Loads should I use?

*1 G Vertical-sanity check of models and hardware•Vertical load to simulate typical fatigue type events•High Vertical load to simulate large vertical events•Lateral Load to simulate cornering (both directions!)•Braking load-forward braking -include weight transfer if it is significant•Braking load-reverse braking•Twist Load- 2 G one side, Zero G other•Miscellaneous Loads significant to your application

•Towing•Jacking•Racing




-For each load also assign a stress criteria

Suggestion:-Fatigue loads- 50% of ultimate stress maximum-1-10 time occurrence loads - yield stress-Use a factor of safety based on experience with the vehicle, the manufacturing processes, and vehicle useage.

-Confirm the loads when you have a vehicle



1 G Load CalculationFront Design Weight= 350 lbsRear Design Weight= 400 lbsDesign=car + driver + instrumentation + full fuel

175 lbs

200 lbs

200 lbs

175 lbs



2 G Load CalculationFront Design Weight= 350 lbsRear Design Weight= 400 lbsDesign=car + driver + instrumentation + full fuel

2*350=700 lbs front weight700/2=350 lbs/wheel

2*400=800 lbs rear weight800/2=400 lbs/wheel

350 lbs

400 lbs

400 lbs

350 lbs



1 G Vertical + 1 G Lateral Load CalculationFront Design Weight= 350 lbsRear Design Weight= 400 lbsDesign=car + driver + instrumentation + full fuel

*Note that the loadcase ignores weight transfer and the front/rear roll couple distribution

175 lbs

200 lbs

200 lbs

175 lbs

175 lbs

175 lbs

200 lbs

200 lbs

350lbs frt/2 = 175 lbs/wheel

400 lbs rear/2 = 200 lbs/wheel



1 G Vertical + 1 G Braking Load CalculationFront Design Weight= 350 lbsRear Design Weight= 400 lbsDesign=car + driver + instrumentation + full fuel

*Note that the loadcase ignores fore-aft weight transfer

175 lbs

200 lbs

200 lbs

175 lbs

175 lbs

175 lbs

200 lbs

200 lbs

350lbs frt/2 = 175 lbs/wheel400 lbs rear/2 = 200 lbs/wheel


Agenda


� Introduction





� Summary


Building & Running Multibody Models



Load Calculation Methods

-Hand Calcs (2d or 3d Free Body Diagram)

-Excel Spreadsheets

-Complete Suspension Exerciser Models

-Full Dynamic Models



MotionView - Preprocessor for building suspension models

MotionSolve -complete dynamic solver for MBD solutions

Hyperview -Postprocessor for most CAE results


Agenda


� Introduction





� Summary


Post Processing and Checking the Loads


Agenda


� Introduction





� Summary


Applying Loads to a Finite Element Model


Summary

Questions?

Suspension and Chassis Loads using - Altair University and Chassis Loads using Michael White ......

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