parametric surface modelling for rapid shell mesh setup of railway vehicle car-bodies

siemens.com/answers © Siemens AG 2013 – All rights reserved.

Parametric Surface Modelling for

Rapid Shell Mesh Setup of

Railway Vehicle Car-bodies

Altair Technology Conference 2013, Turin, Italy

DI T. Grausgruber*

C. Ecker

Dr M. Seitzberger

Siemens Rail Systems

Urban Transport Vienna

2013-04-24

© Siemens AG 2013 – All rights reserved.

Infrastructure & Cities Sector, Rail Systems Grausgruber et al. ATC 2013, Turin

AGENDA

What?

Introduction of railway vehicle car-bodies

Why?

Motivation and objectives

How?

„FastFE“ process description

Features of the CAD surface model

Automated FE preparation in HyperMesh

Conclusions

2013/04/24



Siemens Infrastructure & Cities sector

2013/04/24



WHAT?

Railway vehicles – car-bodies

Main load carrying mechanical structure = car-body (e.g. aluminium metro)

Made of thin walled extrusions and/or sheet metal FE shell meshes

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WHAT?

Exemplary modifications of the car-body

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WHY?

(1) Automated midsurface generation fails

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3D volumes of

alu extrusions

(length ~20m)

auto-

midsurfaces

midsurfaces for

FE analysis



WHY?

(2) Reduction in lead time

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WHY?

(3) Reducing costs

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HOW?

„FastFE “ process description

2013/04/22

Efficient Modification of Global Parameters

• width, height, length of car-body

• distance between pivots, tapering

• side wall type (straight, contoured, ...)

• positions and dimensions of windows

• positions and dimensions of doors

• profile cross-sections, ...

Automated Setup of FE Model

• import and geometry cleanup

• create materials and physical properties

• mirror model (exploiting symmetries)

• enforce surface connectivity

• automated mesh generation

• create entity sets



HOW?

Key aspects of CAD midsurface implementation

Parameterized CAD surface model represents midsurface geometry

Assembly hierarchy with strict top-down reference structure

Global parameters in sketches control propagated reference entities

Local features and sketches to create geometry in subassemblies

fix and flexible zones of the design are defined foresightfully

Wide range of efficient modification possibilities

Parameter alteration (e.g. dimensions, No. doors/windows, …)

Change of design principle (e.g. sidewall type, longitudinal floor

extrusions transverse)

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HOW?

CAD surface model: Top-down reference structure

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HOW?

CAD surface model contains FE information

FE data via colour definition of faces and lines:

sheet thickness

material assignment

areas for creation of loads and boundary conditions

Models contain abstraction issues:

ready to mesh with shell elements

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HOW?

Automated FE model setup in HyperMesh

HyperMesh scripting for perfoming the following tasks:

Create assembly hierarchy, materials, physical properties and entity sets

decode colour information (e.g. sheet thickness, beam diameter, …)

Exploit geometrical symmetry by mirroring a quarter or half model

create front/back and left/right load and boundary condition entities

Enforce surface connectivity

After model setup checks and occasionally minor fixes

Run automesher

Perfom model checks, ballasting and load/boundary condition matching

Export solver input deck and include loads and boundary conditions

Ready to run FE solver input deck

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Conclusions

Soft-coupled CAD-CAE approach to generate FE shell meshes of car-bodies

Versatile CAD template midsurface models:

already contain abstraction issues

use sophisticated parameterization very fast project derivation

already contain necessary FE information on surfaces and lines

Efficient automated setup of high quality FE shell meshes in HyperMesh

Method enables a change from traditional design driven analysis to an

analyis driven design

Successfully applied in the concept stages of several Siemens railway

projects

2013/04/24



Questions?

2013/04/24

Thank you for

your attention!

parametric surface modelling for rapid shell mesh setup of railway vehicle car-bodies

Business

rail systemsgrausgruber

comanswers siemens ag

automated fe model setup

fe information fe data

half model

necessary fe information

length of car

automesher perfom model