Assignment 2-RADIOSS Engine File Editing & 3D Meshing Challenge
OBJECTIVE:
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 the length of the 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 an impact-this will
require a termination time equal to the time it takes for the sound to travel the length of the railfset 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:
Related Courses
1. Check the material properties of the rail component and calculate the speed of sound in steel rail
- So to check the material properties of the material of the rail component. We have to import the component in the hypermesh.
. We have the rad file. So for that, the profile should be RADIOSS
Now we will go to material property and check the values.
where E = Young's modulus
p= density
Ref Rho:0.0078
E:210000.0
So speed of sound (c) = √210000/0.0078 =5188.745m/s.
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.
• Shock wave travels at the speed of sound.
So
• shock wave speed = speed of sound=5188.745 m/s
• time (t) = Distance (D) /speed of shockwave
t=1000/5188.745 = 0.1935s
3.Time for sound to travel length of rail
time (t)= Distance (D) / speed of sound(c)
t=1000/5188.745 = 0.1935s
4. Edit the engine file so that the stress wave can be monitored, moving from one end of the rail to the other during an 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)
The engine file edited according to the above calculated values, its shown in below image
5. Set the frequency of animation output to time that will give 20 animation steps:
frequency=time/no.of revolutions
=0.1935/20
=0.009675
6.Change /print -10.
Set the N_print value as -10.
7.3d meshing tetra mesh
PROCEDURE
MESHING OF HOUSING PARTS USING 3D TETRA ELEMENTS
The HM file of housing parts was imported in Hypermesh. There were 2 parts, one was the cover and the other was a hub • They were not at all disturbed, and almost no errors were present in the geometry. Both the disc and the hub were meshed by converting 2d shell elements into 3d tetra elements, using 3D tetra mesh Tetra mesh.
Performing the 2d shell mesh:
Now the 2D meshing is performed using only tria elements and all the shell kept under the mentioned quality criteria. go to 2D>automesh> element size >5 >type >tria >mesh
. After the shell mesh is performed they need to be converted into solid tria elements. So select the 3D> tetra mesh option
Then select the elements under the fixed tria/quad to tetra option and then do the mesh
NOW , we make 3d tetra mesh
. Now we want the tet collapse to be less than 0.15. So we are going to check that from the check elements. In that, we are going to the 3-d and we are going to give the value of tet collapse to be 0.15 and we are going to check that how many of the elements are failing for the tet collapse.
final model after 3d tetra mesh
3D HEXA MESH
After importing the model in Hypermesh, we will look for surface defects in the model in order to perform Geometry cleanup. As there were no surface defects in the model, we will proceed for meshing. There are four components in the model which are base, arm curve, arm straight and boss. So we will mesh them one by one. At first, we will mesh base component as it can then be useful to mesh the other three components. We will make it as our current component and hide all other components. For base component, we will create 2D mesh on its top surface by selecting the mesh type as mixed. So basically we will create all 2D quad elements on the surface. To convert it to 3D hexa elements, we will offset these elements. So we will go to elem offset panel in 3D page. Here, under solid layers panel, we will select the 2D elements to offset, mention the number of layers as 5 and total thickness which is measured as 25 and then click on offset command. This will create 3D hexa elements by offsetting the 2D elements in 5 layers to a thickness of 25.
Now, we will mesh the component connecting the base which is arm_curve as the base component has the imprint topology of arm_curve component. We will make it as our current component and hide all other components. The geometry for this component is like a partial Torus. So we can spin the elements to obtain 3D hexa mesh. So we will navigate to spin panel in 3D page. Here under spin elems sub panel, we will select the 2D elements from the imprint area, enter angle as 90, on spin as 25 and select x-axis as our rotation axis. For base point, we will navigate to distance panel by F4 shortcut key and create a center node with the help of three nodes option. This center node will be used as the base point and then we will use spin option to spin the elements. Thus the 3D hexa elements will be created along the geometry profile in 25 layers.
Now, we will mesh the component connecting the arm_curve which is arm_straight. As this component has tapered geometry, we will perform linear solid command to obtain 3D mesh. We will need 2D elements or faces to create linear solid. So we will create faces from the 3D hexa elements of arm_curve component. We will navigate to faces panel in Tool page, where we will select the elements of arm_curve and then click on find faces. This will create faces on the arm_curve elements. On the other tapered surface of the arm_straight component, we will create 2D mesh in such a way that the nodes and elements are exactly corresponding to the opposite face as shown below,
Now we will perform meshing on Boss component. We can mesh this component using general solid map since we also have to connect the mesh to the elements of arm_straight component. At first, we will project an outermost node to one of the plane surfaces of the component using project command. Then we will create 2D mesh on the other plane surface. Then we will navigate to general sub-panel under solid map panel in 3D page. Here, we will specify source geom to none, dest geom to be the opposite surface, elems to drag will be the 2D created elements, along geom to be the node path and then click on mesh. This will create 3D hexa elements connecting the elements of arm_straight component. These elements will be stored in a new component named solidmap. We will move these elements to boss component using organize command. Thus the mesh is as follows.
FINAL RESULT
