Assignment 2

Objective: To calculate the speed of sound in steel rail, calculation of time for propogation of sonic wave for a length segment, altering the values in starter and engine file, 3D meshing the components and running a simulation.

1. Check the material properties of the rail component and calculate the speed of sound in steel rail

From the starter file we can clearly see the values

E = 210Gpa

ρ= 7800Kg/m³

^`c=√E/ρ`

`c=√(210*10^9/7800) m/s`

c=5188.745m/s

Speed of sound in steel of E=210Gpa and density of 7800Kgm³ is 5188.745m/s

2. The length of the rail is about 1000 mm.calculate the time taken for a shock wave to travel from one end of the rail to the other

`T=L/c`

`T=1000/5188.745`

`T=0.1927ms`

3. Time for sound to travel length of rail is 0.1927ms

4. 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)

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

For 20 animations the dt wiil be `0.1927/20=0.009635` 

6.Change /print -10.

7.1 3D Meshing tetra and hexa

1. opwn the .hm file in hypermesh

2. Modify surfaces(Split Surfaces) to get better mesh flow

3. Start Meshing one component at a time

4. 3D spin the elements at right angle

5. Use the linear solid to mesh  the component 3

6. Split te surface to get the better mesh flow

7. 2D mesh the component and convert it into 3D elements

8. Final Image

7.2 Model 2

1. Open the .hm file in Hypermesh

2. Start 2D meshing one component at a time

Note: Mesh Style: Only Trias

Element Target Size: 5

3. Now Converting these elemens to tetra mesh

4. Now Mask some of the elements to checks for tetras inside the model

5. Check for quality of tetra mesh using F10

 

.out file of the changed simulation

 

Various energy plots of the simulation

Conclusion:

• Speed of sound in steel of E=210Gpa and density of 7800Kgm³ is 5188.745m/s
• Time for sound to travel length of 1000mm is 0.1927ms
• Editing the Engine and starter file
• For 20 animations the dt wiil be `0.1927/20=0.009635`
• 3D meshing the components(Quads and hexa mesh)
• Runing simulation for the metal rail