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

AIM:

To edit the given engine file and perform 3D mesh for given model.

GIVEN:

Engine File Snippet

Questions:

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

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

3.Time for sound to travel length of rail?

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)

6.Change /print -10.

7.3d meshing tetra mesh and hex mesh

• Repeat class examples and, maintain the quality.
• Target tet size=5mm,hex size=10mm,tet collapse=0.15.

PROCEDURE:

• Calculate the speed of sound in steel rail

Formula for "Speed of sound"

C= `√`E/`√ ρ`

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

STARTER FILE

E=210000 Mpa(N/mm^2)

`ρ`=0.0078 g/mm^3

c= `√210000/0.0078`

speed of sound in steel rail c= 5188.75 m/s

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

Formula for time taken

t=l/c
t=1000/5188.75
t=0.1927ms(milli seconds)

• Time for sound to travel length of rail is = 0.1927ms
• The given engine file edited using found values

ENGINE FILE

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

T frequency = Termination time/No.of Animation steps
= 0.1927/20
T frequency = 0.009635 Hz

• Change /print -10
• 3d meshing tetra mesh and hex mesh
• To mesh the given file and connect it by any one 1D connector
• Directly open the .hm file into the software
• Mesh both the surfaces

MESHED MODEL

• Go to 1D>connectors>rods select any two nodes to connect,
• Now the connection is done , after which new property card should be assigned to the component with property card image of "P2_Trus"
• The final result is shown in below image

WITH 1D CONNECTOR

MODEL 2 :

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

• Check for any geometrical error, in this case we dont have any so carry on with 2d mesh first
• Mesh the each components according to the given quality criteria with tria elements
• Now we have to convert the 2d mesh element to tetra elements by 3d>tetramesh select the elements and mesh with required tet collapse value

• Do the same to the other components and make sure no tet collpase errors should be present

MODEL 3 :

• 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 and solid map
• By using these methods we perfrom hexa mesh on each component,
• It depending upon the components geometry
• First mesh the base top surface with only quad element and use element offset option

MESHED BASE

• Next component is curved arm,to mesh this model select the common 2d element between base and arm curve component,spin the element using
  base node and axis to rotate

CURVED ARM MESH

• To mesh the arm straight component,use 3d→linear solid option
• We should mesh each end by 2d element and join the same in this method
• Already one end of arm stright component is meshed by hexa element
• To extract 2d element from hexa element , go to tools→faces extract faces option
• One end of the component will have 2d elements, mesh the other end with same number of elements to avoid penta elements.

MESH TILL STRAIGHT ARM

• To mesh the boss component we will be using Solid map option
• Mesh the boss one side and solid map the element to the other end by nodes
• Now after meshing all the components by hexa elements we have to delete all the 2d elements present in the model

FULLY MESHED MODEL

CONCLUSION :

• Understood how to calculate speed of sound in different material, frequency, time step and to read input radioss file and also import the radioss solver deck file anf feed the value and finally to export the file in .rad format.
• Additionally Got to know how to create 3d tetra mesh and hexa mesh and Learnt how to give diffrent type of 1D connection and hyperbeam concept.