Creating the 2D and 3D meshing for the given models.

OBJECTIVE

The main objective of this project is creating the 2D meshing of the Housing and Arm Bracket and then finally to 3D meshing Tetra mesh and Hexa mesh having target element size is 5mm, Hexa size 10mm, tet collapse is 0.15 . As well as we will solve some numerical problems by taking datas from Radioss file and edit the engine file.

INTRODUCTION

Time step is the time required for a shock wave to propagate across the smallest distance in an element.

Tetra:-The tetra elements also known as tetrahedron elements. the tetrahedron elements consist of four triangular faces, six straight edges, and four vertex corners.

Hexa:- The Hexahedron is any polydrone with six faces. A hexaderon is a regular cube with all its faces square and there squares around each vertex.

Questions and answers:-

Q1) Check the material properties of the rail component and calculate the speed of sound in steel rail?

ANSWER:-

Given data from FIRST_RUN_0000.rad

Young's Modulus(E)=210000 g/mm^2

Material Density(rho)=0.0078 g/mm^3

as we know,

Speed of sound(c)=`sqrt (E/rho)`

c = `sqrt (210000/0.0078)`

c = 5188.74 mm/ms.

Q2) The length of the rail is 1000. Calculate the time takes for a shock wave to travel from one end of the rail to other?

ANSWER:-

Given length(L)=1000mm

Speed of the sound in rail(c)=5188.74 mm/ms

`/_\\te=L/c`

`/_\\te=1000/5188.74`

`/_\\te=0.19272` ms

so when the length of the rail is 1000mm,then to total time taken by shock wave to travel from one end to other is 0.19272 ms.

Q3) Time for sound to travel length of the rail ..................................?

ANSWER:-

So when the length of the rail is 1000mm,then to total time taken by shock wave to travel from one end to other is 0.19272 ms.

Q4) Edit the engine file so that the stress wave can be monitored, moving from one end of the rail to the other during impact-this will require a termination time equal to the time it takes for the sound to travel the length of the rail (set on /RUN card)?

ANSWER:-

• At first engine file is imported in Hyperworks

• In solver browser in ENG_RUN edited the termination time i.e Tstop=0.19272

Q5) Set the frequency of animation output to a time that will give 20 animation steps(/ANIM/DT)?

ANSWER:-

Given data,

Frequency of animation(f)=0.19272

No. of animation steps(n)=20

so,

Time frequency(Tf)=`0.19272/20`

Tf = 0.009636 hz

Q6) To change/ print -10

ANSWER:-

• Edited rad file:-

Q7) 3d meshing Tertra mesh and Hexa mesh

• Repeat the class example and, maintain the quality.
• Target tet size=5mm, Hex size=10mm, Tet collapse=0.15

HOUSING

At first the model is imported into the Hypermesh.and as the given model has two parts 1)Cover and 2)Hub. so to mesh the whole model we need to mesh it seperately one by one.

• HUB

Hub is consired to be mesh at first so at first 2D Mesh is created on hub part and then this 2D mesh is coverted intO 3D mesh.

2D mesh generation:-

Click on 2D mesh panel-->automesh-->Tria(5mm)-->Mesh

Conversion of 2D into 3D mesh:-

Click on 3D mesh panel-->Tetramesh-->selection of element-->Click on element parameter(min tetra size=3.75mm)-->tet collapse-->0.15-->mesh

• COVER

Next part is Cover, same process is followed as Hub.

After creating 3D mesh check whether the tet collapse value i.e 0.15 did not fail.To check it unhide both hub and cover, and check all the meshing elements.

ARM BRACKET

Given model is imported into hypermesh, and as the given model has many parts so meshing is to performed in each parts separately one by one.

different parts of Arm Bracket

i) BASE

ii)ARM CURVE

iii)ARM STRAIGHT

iv)BOSS

BASE

Click on 2D mesh panel-->surface selection-->Give element size-->select quads only-->mesh.

Element offset-->select solid layer-->element to offset-->generate 2D mesh-->follow geometry-->select the surface and give the no. of layers 5-->total thick(25mm)-->offset.

ARM CURVE

Mask-->element-->configure-->hex8-->select entities -->mask.

Then centre point is created .

then, Spin-->select the spin element-->90 degree-->25 elements in spin-->select centre point-->x-axis as normal plane-->spin.

ARM STRAIGHT

For Arm Straight we used linear solid option.At first both faces, initial and destination faces were meshed with 2D element by taking care of no. of eqal nodes on both sides. Finally at the end delete the 2D element.

BOSS

For boss solid map feature is used, one circular face is meshed with equal no of nodes which had in arm straight face in order to have QUAD elements. After successfully creating the 2D QUADS, make sure to project and duplicate the nodes at the another side of the boss.

Solid map-->Select destination geometry-->select unmeshed opposite surface-->drag element-->mixed--> path-->select the nodes arm-->line-->boss-->mid line-->give element size-->mesh.

finally delete all QUAD4 elements.

After meshing 3D elements were checked for tet collapse i.e 0.15. To check it few element were masked and found that the tet collapse values were not failing the desired.

CONCLUSION

Clearly understood how to import .rad file into hypermesh and how its elements properties can be edited.

Also got the knowledge about the 3D meshing using 2D meshing. also learn how to deal with complicated geometry in less and efficient time.

All the questins were answerd successfully.