1 Concept Level Automotive Structural Analysis using COMSOL

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Concept Level Automotive Structural Analysis using COMSOL® 14 -10 -2020 Authors : Mihir Bhalerao, T K Hareesh, Alok Thanapati, Chandrakant Deshmukh Copyright © 2018 Mahindra & Mahindra Ltd. All rights reserved. 2

Content § § § Company Overview Problem Statement : Frontloading Performance Targets Why Structural Simulations? Beam Modelling & Simulation Process Equations Global Stiffness Analysis Eigenfrequencies Application Builder & COMSOL Server Analysis Process Flow Conclusions Way Forward 3

Company Overview : Mahindra & Mahindra Ltd 4

Automotive Sector Overview 5

Problem Statement : Frontloading Performance Targets § During concept phase of program, robust concept 3 D CAD data will not be available. To create CAD data, structural concepts need to be generated & evaluated § To generate a concept, the critical parameters of the system and sensitivity of each parameter in response to the performance target need to be understood. § Performing DOE or Optimization through multiple CAD proposals is time and resource consuming. § A Robust Structural Concept which leads to matured CAD proposal will help reduce iteration at detail engineering phase. 6

Why Structural Simulation? § Multiple vehicle level targets such as Durability, NVH, Ride & Handling, Safety etc. are affected by structural systems and are critical to customer satisfaction § Vital cog in vehicle architecture development § § process First time Right design essential for timely product development Have a long lead time in terms of design & validation Different Body Constructions have different structural requirements 7

Beam Modelling & Simulation Process Parameterization of the structural system Parametric Wireframe generation in COMSOL Section Details Input Loads & Constraints as per Standards Model Validation with Existing Vehicles Beam Modelling Advantages : § Light, Flexible, Quick and fairly accurate § Easy to make parameterized models § Can run multiple iterations for DOE/Optimization § No requirement for 3 D CAD 8

Calculations for stiffness & eigenfrequencies § Equations For Eigen frequency § Equations for Bending Stiffness • Equation of Motion without Damping § Equations for Torsional Stiffness • Equation for Frequency 9

Global Stiffness Analysis Bending Stiffness Loading & Constraints Results Point Force Constraint Point Force Z Displacement Plot Force is applied at the centre and the Z-displacement is measured 10

Global Stiffness Analysis Torsional Stiffness Loading & Constraints Results Constraint Moment Constraint X Rotational Displacement Plot Moment is applied and the rotational displacement is measured at the load application points 11

Modal Analysis : Eigenfrequencies Loading & Constraints Free – Free Condition Results 1 st 12 Eigenfrequencies & Mode Shapes 12

Application Builder & COMSOL Server § Application Builder in COMSOL enables Democratization of Models for Engineers § Parametric Model gives flexibility of Design Iteration § Quick Analysis at concept level gives more scope at CAE analysis level. 13

Analysis Process Flow Design of Experiments Optimization Targets Regression Equation Optimization Proposals Generated from the Optimization Sr no. A B C D Weight TS BS Proposal no 1 Proposal no 2 Proposal no 3 Reference Vehicles Reference 1 Reference 2 *Minitab Software used for statistical analysis 14

Conclusions § Using the integration of COMSOL® tools (Multiphysics, App Builder & COMSOL server) for beam modelling , structural concepts can be generated quickly § Fast runtime (each iteration takes less than 2 minutes) and closely accurate simulation results (>80% correlation for all performance attributes) makes it possible to run multiple DOEs & optimizations § Performing multiple DOEs & Optimizations with the studied methodology for global stiffness and modal frequencies evaluation using beam modelling aids to a robust structural concept without 3 D CAD. 15

Benefits 16

Way Forward Structures Further Analysis Expansion of current methodology for robust concept generation of other automotive structures such as the cargo, different body structures Cabin Cargo Body Enhancement of analysis scope for inclusion of other structural contributors such as durability and crash during concept phase Crash Analysis Durability Analysis 17

Acknowledgement § We would like to thank our teammates at the advanced engineering dept. and methods dept. at Mahindra & Mahindra. § We would like acknowledge the timely support & guidance by our Ho. Ds : Mr. Samir Rawte, Mr. Sridhar Lingan § We also thank the COMSOL support team for modelling support and smooth query resolution 18

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