Engine file editing and 3D meshing Tetra mesh Hex mesh

Objectives:

1. To calculate the speed of sound in steel rail

2. To calculate time taken by shock wave to travel from one end of rail to other

3. To edit the Engine File

4. To create 3D Tetra and Hex mesh on given components

Solution:

1. To calculate the speed of sound in steel rail:

Material Properties:

Young’s Modulus, E = 210000 gm/(ms)²(mm)²

Density, ρ = 0.0078 gm/(mm)²

Formula:

Speed, C = `sqrt (E/rho)`

= `210000/0.0078`

C = 5188.745 ms

2. To calculate time taken by shock wave to travel from one end of rail to other:

Length of rail, L = 1000 mm

Speed of sound in steel, C = 5188.745 ms

Formula:

Time taken, δt = `L/C`

= `1000/5188.745`

3. Time for sound to travel length of rail, δt = 0.192 ms

4. Engine file was modified with the calculated value, to monitor the stress wave, by setting the termination time equal to the calculated value of time required for sound to travel the length of the rail :

5. To set the frequency of animation output to a time that will give 20 animation steps = `0.192/20`

= 0.0096

6. To change /print -10

7. 3D meshing:

A. Hub and Cover:

Steps followed:

Make Hub current component.

Use Automesh tool to create Tria elements on the hub surface with given target size.

In the 3d toolbox, use Tetramesh tool to create 3d elements from the created 2d mesh.

Mask a few elements to make sure that Tetramesh is generated.

Press F10 and in the 3d menu check if the tet collapse is within the given limit.

Make Cover current component.

Various methods can be used to create Tetramesh on this component(like Volume tetramesh, Quick tetramesh, creating 2d mesh and then converting it into 3d), I have used the Volume Tetramesh tool.

B. Arm Bracket:

Steps followed:

Hide all components except Base.

Create 2d mesh with ‘Quads only’ setting over the base.

In the 3d menu, use the Element offset tool to create Hex8 elements with calculated parameters (based on thickness of the base).

Make the Arm curve visible, and locate the centre of the arm’s curve.

Mask the Hex8 elements to make the 2d elements on the face of the base visible.

Use the ‘Spin’ tool, and create the 3d elements by properly selecting all the parameters as explained in the video.

Make the Arm Straight visible, and create a 2d mesh over its end connected to the Boss.

The no. of elements on the Arm curve’s face and the Arm straight’s face should be kept equal.

Make the Face on Arm curve visible.

By using the Linear Solid tool, create the 3d elements on the Arm straight.

Make the Boss visible and generate a 2d mesh over one of its faces.

The no. of elements is to be taken care of as explained in the videos.

By using the Solid Map tool, 3d elements were generated on the Boss.

Delete all the Faces that were made visible.

Delete all the 2d elements that were created earlier.

Results & Conclusion:

A method to calculate the speed of sound through different materials was learnt.

Various tools required for 3D meshing were learnt.

Link for files: https://drive.google.com/open?id=1AQUl4tDsCTMi2JnlPg3qoypk11gwHIAZ