Automotive Topology optimisation using Genesis.

“Current methods and directions for the future”

Dr Tayeb Zeguer – Jaguar Land Rover Ltd.

Prepared by Bindu N Ali

Location:

9th July 2012

Overview

Introduction to Advanced CAE Group

Topology Established Techniques

JLR current Topology approach to Nonlinear, crashworthiness and Pedestrian head impact

Future Vision for topology optimisation for both technology and integration

Conclusions

Introduction to Advanced CAE group Body CAE – ‘Support the CAE needs of the whole vehicle NVH,

Durability and Crash worthiness functional performance analysis’

SFE Modelling for

use in rapid

development studies

Programme Support

Early Concept Development

Methods Development

Multi Disciplinary Optimisation

Feasibility & cost

Topology Optimisation: Established Method Solid Topology

Many of the standard methods available within Genesis have been applied to everyday tasks in vehicle development,

examples of these include:

Solid Topology

Developing the rib pattern for a cast aluminium suspension turret considering NVH requirements

Established :Reinforcement Derivation Method

Primary Uses:

• Search for new load paths

• Identify weak joints

• Indicate poor areas with poor connection

RDM benefits:

• Identify new load paths, poor connectivity and poor joint condition

• Can be applied at any time in vehicle development program

Established :Reinforcement Derivation Method

Multi Load Cases

NVH Load Cases

Torsion

Bending

FFB Side MDB

ODB Side Pole

Rear MDB

Crash Load Cases

Established :Reinforcement Derivation Method

RDM Topology Results

Example Poor Joint Condition (Sled Runner section doesn’t feed

load into rear floor)

Topology Optimisation: Established Method Geometry Changes

The Topology indicates that changes to the geometry would improve the efficiency of the structure

Examples of Geometry Changes

Connection between wheel arch and body side Reinforcement for Seat Mount Stiffness

Reinforcement for Turret Vertical Stiffness Reinforcement at bottom corner of tail gate opening

Topology Optimisation: Established Method Topography Optimisation of Turret

A separate topography was carried out to achieve greater vertical stiffness

Topography

Initial shape Final shape

Topology Optimisation: Established Method Topometry and Sizing Optimisation

Sizing Topometry

JLR current Topology approach to Non-Linear Crash Optimisation

Objective:

• To develop a method to carry out concept optimisation of a vehicle structure in for multi

load cases (MDO)

Benefits:

• Ability to handle thousands of design variables, opening methods like Topology, Topometry

and Topography to crash

• Ability to consider NVH load cases at the same time

• Due to coupled nature of simulation contacts are considered

• No need to create approximate load cases

• Automated management tool, runs in the background until convergence

Extensive thickening of

tunnel sides and bulkhead to

reduce intrusion from engine to

bulkhead impact

Diagonal thickening indicates need for bracing to prevent bellying of tunnel

sides and creating a load path out to the

sills (as shown)

Example 1: Non-Linear Crashworthiness Topometry

• Longitudinals, crush cans and bumper beam

• Bumper beam reduced to minimum (as expected for FFB only optimisation

• Crush cans increased to absorb more energy in high speed

• Major BIW Components

• Tunnel and sill inners thickened

• Subframe thickness varied to create load path

• Bulkhead, floor, swan neck internals & subframe rear legs

• Outboard sections of swan neck reinforcements increased in thickness

• Floor to tunnel intersection region increased to maximum allowable

Example 1: Non-Linear Crashworthiness Topometry

Example 2: Non Linear Methods – Head Impact

Objective: To develop a method to carry out concept topology optimisation of bonnet

reinforcement considering both static strength and dynamic pedestrian requirements

• NVH Requirements

> Torsion

> Bending

> Rear Beam Stiffness

> Corner Stiffness

> Centre of Pressure Load

• Safety – Head Impact Requirements

> Adult and Child Head Impacts

Example 2: Non Linear Methods – Head Impact

Linear Topology Optimisation

LS-DYNA Model Update

LS-DYNA Head Impact Simulations

Use HIC Feedback to adjust Constraints

Automation Panel Automated Management Process

CSV File Containing Impact Points Define Head Model

LS-Dyna Base Model

Designable Parts

Target HIC

Launch Optimisation

Genesis Base Model

Example 2: Non Linear Methods – Head Impact

Topology Results Considering:

• Torsion

• Bending

• Rear Beam Stiffness

• Head Impacts

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Optimisation History

Objective

ConstraintViolation

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LS-DYNA HIC Vs Design Cycle

Topology Result for Each Design Cycle

Future Vision – Optimisation Technology

Features in the Tool:

• Development of Non-linear Topology such as for crash and general non linear loading

• Integrated Acoustic Optimisation

• Additional Manufacturing Constraints, i.e. shell casting

Uses of the Tool:

• Automated link from topology to shell mesh or geometry (CAD).

• Access to Optimisation for AVA/CAD engineers

• Implementation of new genesis features into existing processes e.g. contact optimisation

Conclusions

Linear topology is very well established and used regularly at

JLR including applications with composite materials

JLR has been pioneering the use of non linear topology with

currently available technologies and driving further development

Non linear topology, acoustics and process automation need be

developed and embedded into the current software.