Meshing a back door component of a car using hyper-mesh (Optistruct) in order to facilitate durability analysis on the component

OBJECTIVE :

The aim of this tool test is to mesh a back door component of a car using hypermesh(Optistruct) in order to facilitate durability analysis on the component

Element quality criteria :

S.N	Quality Criteria	Value
1	Target Element Length	5
2	Aspect Ratio	3
3	Skewness	45
4	Warping	30
5	Taper	0.5
6	Min. Length	3mm
7	Max. Length	7mm
8	Min angle Quad	45
9	Max angle Quad	135
10	Min angle Tria	30
11	Max angle Tria	110
12	Tria %	15

PROCEDURE

The procedure required to accomplish this task is done in four major step.

1. Import And Geometry Check Of Component
2. Generation Of Midsurface and Geometry Clean-up
3. Meshing Of The Component
4. Adjusting Mesh To Meet Quality Criteria
5. Making Necessory Checks On Final Mesh

Import And Geometry Check Of Component

• The geometry is first imported using the import tab and specifing the file type,be it Step,Iges etc.
• Once the geometry is imported it is important to check the geometry for error and clean up before going any further. In the case of this component, i removed unneccesory duplicates which could hinder the operation.
• The imported model was different. It had 197 components which was quite messy for me.

• I created three different components and i moved all 197 components using organise tab into those three component to make my work easier and deleted the unused components

Generation Of Midsurface and Geometry Clean-up

• After the pre-cleanup, midsurfaces of the backdoor is created. The backdoor now has three separate bodies and the mid-surface is generated separetely for each part using surface offset.
• After the midsurfaces are created , the components are prepared for 2d meshing
• All three components are symmetric so they are both split from their centre and then the other half is deleted.This is to ease the meshing task.
• The components are cleaned by toggling unecessory lines that can cause problems during meshing.It can be seen from the figure below that lines connecting together with distance more than the minimum meshing lenght are toggled and adjusted

BODY 3

BODY 2

BODY 1

Meshing Of The Component

Before starting meshing, i identified certain areas which can make the meshing task dificult and i created split surface lines to section these surfaces to make my meshing easier.

• These sections are made on both components( hood, Body), as a preparation for meshing
• It is important to view all colour lines and inspect the mid-surfaces for errors before starting the meshing.Cleanup is done with variety of tool such as, toggle edge,filler surf,add/remove point, split surface-node,ruled spline surfaces etc
• I stated meshing surface by surface and adjusted element density to obtain obtimum mesh quality and flow. (Element size of 5mm)
• Below are images of final mesh images all three components. Note that the components mesh was reflected together wirh the midsurface to form the complete part, after meshing.

BODY THREE MESH

Half mesh

Full reflected midsurface

Full Body Three mesh on midsurface

BODY TWO MESH

Half mesh

• Full reflected midsurface

Full Body Two mesh on midsurface

BODY ONE MESH

Half mesh

Full reflected midsurface

Full Body One mesh on midsurface

Making Necessory Checks On Final Mesh

• When meshing is complete there are some checks that i made to check my mesh.
• Checking for edges
• Checking for duplicates
• Checking for normals
• Finally creating and assigning a material and propety to the components

Images of checking normals

RESULTS AND CONCLUSION

Below is an image of the final mesh of all three components after generation and their quality mesh criteria failure percentages.

CONCLUSION

The components where mesh successfully and passing all quality criteria set in the tool test. Below is an image of the final meshed component.