RNL-08 Drop Test Simulation Valeo

8/11/2019 RNL-08 Drop Test Simulation Valeo

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Simulate to Innovate 1

Drop Test Simulation of Automobile Alternator using AltairRADIOSS

SivaSankar Reddy. ASr. Engineer CAE

Valeo India Private limitedSholinganallur

Chennai 600 119.India

Thangavelu. CEngineering Manager

Valeo India Private limitedSholinganallur

Chennai 600 119.India

Karthic SethuramanEngineering Manager

Valeo India Private LimitedSholinganallur

Chennai - 600 119India

Keywords: Automobile alternator, Drop test, Altair RADIOSS,

Abstract

An alternator is an electromechanical device that converts mechanical energy to electrical energy during operation. Alternatorsare used in modern automobiles to charge the battery and to power the electrical/electronic system when its engine is running.Proper functioning and efficiency of alternator is very important in automobile for the functioning of electric devices. The powerneeds to be transmitted from origin point to different locations, to do this there is specific take off live terminal. This take off liveterminal must be prevented from risk of touching other system components.

The main aim of this study is to understand the behavior of assembly and to check the stiffness of parts when it is dropped fromcertain height. The initiation of this study was started after observing the failure of part in field drop test. This study includessimulation on initial design and on modified designs. Altair HyperMesh, HyperCrash and RADIOSS are used to perform thisstudy.

Introduction:

Automobile alternator is a key component in an alternator. The behavior and stiffness of alternator is

checked when it is dropped from certain height. Simulation is performed on initial design to check the

critical regions and results are analyzed. Based on initial simulation results design improvements was

carried and simulations are performed.

Process Methodology:Alternator assembly consists of different sub assemblies like rotor assembly, stator assembly,regulator assembly, and rectifier assembly, front, rear brackets and rear cover.

FE Simplifications:Alternator assembly is complex in nature because of its various subassemblies. Simplifications weredone on various parts and few assemblies considered as lumped masses at the COG locations. Theparts like cover and electronic unit which are critical for study were considered with any designsimplifications.Preprocessing: Altair HyperMesh and HyperCrash is used.Solver: Altair RADIOSS.Post Processing: Altair HyperView and HyperGraph.


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Figure 1: Alternator complete FE model.

Parts considered for simulation:

Figure 2: Rear Bracket with Screws


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Figure 3: Simplified part of electronic assembly Figure 4: Front Bracket

Interface definitions:

The contact surfaces needed for the accurate definition of the interfaces are created in HyperCrashusing self Impact option. Contact Interfaces of Type 7 is created and friction is depending upon thecontact status of the interface, appropriate minimum distance for impact is carefully chosen.

Control Cards and Engine Settings:

Appropriate control cards for controlling strain formulation are used to ensure that the stable timeincrements for the solution are not abruptly low. All required output controls are activated to capturestress, plastic strain and deformation at desired time intervals. History output of Global variables likeInternal energy, Kinetic energy, Hourglass energy and Total energy are requested to monitor theaccuracy of the solution. Appropriate frequencies are defined for writing out results of field variables,global variable and, restart files. Eight processors are used for the engine calculation using HP-MPI inWindows 64 bit operating system.


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Loading Conditions:

Initial velocity is applied to assembly.

Figure: 5 Initial design Figure 6: Improved Design

Results & Discussions:

Deformation Plots:

Figure 7: Initial Design Figure :8 Improved Design


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Stress Plots:

Figure 9: Initial Design Figure 10: Improved Design.

Stresses developed in the initial design are very high compared to modified design.

Benefits summary:

1. User Friendly mesh definition methods in Altair HyperMesh 11.0 has resulted in reducing the pre-

processing time considerably.2. HyperMesh made it easy and quick to modify the mesh from initial to modified geometry whichresulted in considerable time saving.3. Ease of defining contact, User friendly Penetration detection and correction methods in AltairHyperCrash 11.0 has also helped in a reduction of time further.4. The revolutionary Token based Altair licensing ensures that the engineer can prepare a neworientation model in Altair HyperCrash when the RADIOSS engine solution for another orientation is inprogress or read results of a calculation in HyperView or HyperGraph that is already completed.

Challenges:

1. Simplification of geometry to have quick results.2. Selection of appropriate element type, size and control cards for element properties to ensure a

manageable stable time increment for solution.3. Resolution of initial penetration in contact interfaces.4. Arriving at an optimal calculation time (total time of impact simulation) to ensure appropriatestabilization of Global variables (Internal and Kinetic energy) and minimize calculation errors.

Conclusions:

Drop test simulation of alternator assembly using Altair HyperWorks tools has given a considerableconfidence to the Research and development team in the ability to predict the robustness of thedesign at the early phase of product development and identify improvement opportunities if any forfuture concepts.


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Altair tools helped us to find the design solution by showing the critical location on the initial design

and helped us to launch updated designs quickly.

ACKNOWLEDGEMENTS

The authors would like to thank Mr.Sriram.G, R&D Director, Valeo India Private Limited for hisconstant support in documenting this study and sharing it with the CAE community in the AutomotiveIndustry

REFERENCES[1] Altair HyperWorks11.0 Online documentation.

RNL-08 Drop Test Simulation Valeo

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