Assignment 2-RADIOSS Engine File Editing & 3D Meshing Challenge

Assignment 2-RADIOSS Engine File Editing & 3D Meshing Challenge

1) Calculate the speed of sound in steel rail

Sol: Formula for "Speed of sound"

C=√E/ρ

from the given 0000.rad file we can get the material properties of steel rail

E=210000 Mpa(N/mm^2) ;

ρ=0.0078 g/mm^3,

now using the formula mentioned earlier, we can substitute the values and get the speed of light i.e,

c=√210000/0.0078

=5188.75 m/s

2) Calculate the time taken for the shock wave to cross the rail of 1000mm

The formula for time taken t=l/c

t=1/5188.75

=0.1927ms(milliseconds)

3) The time for sound to travel the length of rail is = 0.1927ms

As per calculation of Question no.2.

4) The engine file edited according to the above-calculated values, is shown in the below image

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

SOL: frequency=(l/c)*time

=(1/0.1927)*20

=104 Hz

set the above-calculated frequency in 0001.rad file(import the .rad file into the software and edit the cards) like shown below

6) Set the N_print value as -10

Now after changing all the values Export the solver deck file in .rad format

· The above image is the final radioss engine file after making all the changes

· The same radioss file is attached to the challenge asset

· Steps for 3d tetra mesh model:-

• Open the model directly since it is in .hm format

• Check for any geometrical error, in this case, we do not have any so carry on with 2D mesh first

• Mesh each component according to the given quality criteria with tria elements

• Now we have to convert the 2d mesh element to tetra elements by 3d > tetra mesh select the elements and mesh with the required tet collapse value

• After Meshing Check for if any element is failing in tet collapse

• Here 0 element is failing so we will move on with other component

• Follow the same procedure for the other component and make sure no tet collapse errors are present

Steps for 3D hexa mesh 0f arm bracket model:

• In this model we have four components, one by one we will be meshing the model
• We have different methods to perform 3d hexa mesh-like Element offset, spin, Linear solid, solid map...etc
• We will be using these methods to perform hexa mesh on each component, depending upon the component geometry

Firstly the base is just a rectangular cube it is better to mesh the top surface with only quad elements

Now we will use the command name Line drag to make hexa mesh for Base using 2D meshing

The next component is the curved arm, to mesh this model select the common 2D element between the base and arm curve component, spin the element using the base node and axis to rotate

• To mesh the arm straight component, use the 3D>linear solid option

  We should mesh each end with a 2D element and join the same in this method

  Already one end of the arm straight component is meshed by a hexa element, to extract a 2D element from the Hexa element, go to tools>faces extract faces option

  One end of the component will have 2D elements, mesh the other end with the same number of elements to avoid penta elements

• To mesh the bosh component we will be using the Solid map option

  Mesh the boss on one side and solid map the element to the other end by nodes

  Now after meshing all the components with hexa elements, we have to delete all the 2D elements present in the model

  Go to the delete option select elements by config option and select quad 4 elements, all the 2 elements will be deleted

• 

• CONCLUSION:

1. Understood how to calculate the speed of sound in different materials, frequencies, time step
2. Understood how to read input radioss file
3. Understood how to import the radioss solver deck file and feed the value
4. Understood how to export the file in .rad format
5. Got to know how to create 3d tetra mesh and hexa mesh

Thank you.

Vidhan Shah