## CREATING 3D MESHING AND CHANGING ENGINE FILE PROPERTIES BY EDITING STARTER FILE PROPERTIES

Creating 3D Meshing and Changing the Properties of Engine file by  file Editing the Starter file

Objective:

To be able to create the tetra mesh and hex mesh for given solids with given specifications in Hyper Mesh. Edit the properties of the steel rail component and modify the Engine file with the edited properties of steel rail.

Specifications of solids to create mesh tet size=5mm ; hex size=10mm ; tet collapse=0.15

Case set up and Execution with images:

Note: Unit system used in starter and engine files are Gram (g), Millimetre (mm) & Millisecond (ms).

As per given Questions:

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

Sol:

To find the properties of the steel rail component we need to import the starter file to the Hyper Works.

Change the solver in entities browser and find the required properties of steel rail component from Solver>MAT>LAW2_PLAS_JOHNS>STEEL>Entities Editor

Required properties to find the speed of the sound in steel rail

Modulus of Elasticity (E) = 210000

Density                    (ρ) = 0.0078

Speed of the sound in steel rail ‘C’ = Modulas of Elasticity/Density

C=E/ρ =210000/0.0078=5188.7452

Therefore, Speed of the sound in steel rail is 5188.7452 g/ms

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?

Sol:

Time takes for a shock wave to travel from one end of the rail to the other

‘t’ = Length of the element/Speed of the sound

t=l/c=1000/5188.7452=0.1927ms

Therefore, the time takes for a shock wave to travel from the one end of the rail to other is 0.1927ms and uplode in Entities>ENGINE_KEYWORDS>RUN.

3.Time for sound to travel length of rail=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)

Sol:

Edited engine file

/VERS/140
/RUN/FIRST_RUN_0001/1/
0.192700000000000
/ANIM/VECT/DISP
/ANIM/VECT/VEL
/ANIM/ELEM/EPSP
/ANIM/ELEM/ENER
/ANIM/ELEM/VONM
/ANIM/ELEM/HOURG
/ANIM/DT
0.000000000000000 0.009600000000000
/TFILE/0
0.100000000000000
/RFILE
5000
/ANIM/NODA/DMAS
/DT/NODA/0
0.900000000000000 0.000000000000000

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

Sol:

Frequency of animation output Tfreq=Time for sound to travel length of rail/20

Tfreq=0.1927/20

Tfreq=0.0096ms

Therefore, frequency of animation output to a time 0.0096ms Changing the property of Tfreq in Solver>ENGINE_KEYWORDS>ANIM>ANIM/DT>ENG_ANIM_DT>change the Tfreq as 0.0096

6.Change / Print -10

Sol:

Solver>ENGINE_KEYWORDS>PRINT>PRINT>ENG_PRINT>Edit N_print as -10

7.3D Meshing with target tet size 5mm, hex size 10mm, tet collapse 0.15 and maintain quality

Sol:

Creating the 3D(Housing) mesh with tet size 5mm and check component for tet collapse 0.15

>>Import the solid component on the Hyper Works and create mesh through 2D or 3D menu page in the GUI.

First type, we need create automesh on the surface by selecting the triangle as mesh type and element size 5mm in 2D menu page and go to tetra mesh in the 3D menu page.

In Beginning 2D>Select Surf>Element size 5mm>Mesh type trias>Mesh

After creating 2D mesh then 3D>tetramesh>Change the Elem into comp in the fixed trias to tetramesh(In tetramesh parameters in same tetramesh maintain 3mm as tetrasize and tet collapse as 0.15)>Mesh

Assign Mesh

Quality checking of the component

Go to 3D menu page>Check elements>tetcollapse(0.15)

Hence, there is no elements failed in the tet collapse.

Cover Mesh

After meshing the internal component of the housing then we go to cover tetra mesh which is external part of the housing. This is also similar method but it is directly started from the 3D menu page.

3D>tetramesh>volumetetra>Enclosedvolu-surf>2D type trias>3d type tetras>put element size 5mm>Mesh

Assign mesh

Checking the component for tet collapse

Hence, There is no elements are failed for tet collapse.

Creating 3D(Arm Bracket) Hex size 10mm

3D Hex Mesh

• Solid Map

In the 3D Hex mesh the components the solid is split into different parts…

Import the arm bracket into the Hyper Mesh

In the above attached component, the solid is split into the four different parts i.e., Base, Arm curve, Arm straight and Boss.

1.In meshing exercise hide the rest of the component to mesh base hide arm curve, arm straight and boss.

Creation of mesh on the top surface of base:

Mesh creation is followed by changing the geo to 2D in menu page and selecting the automesh option in the panel area or Press F12 in the functional keys.

Mesh:

2D>Automesh>select the surface>Give 10mm element size & Mesh type Quads only>Mesh

After creation of 2D mesh on the surface of the base component offset the 2D mesh from source face to destination face.

To create the offset go to 3D>elem offset>solid layers>Put elems in 2D elems to offset>along geom to follow surf>number of layers 5>initial offset 0.00>total thickness 25 (by check the distance by F4)>offset+

2.Switch on the arm curve and make the component as current

Now hide the 3D elements on the base components to project the elements to arm curve go to mask by pressing the F5 on the functional keys select the elem by config under the elements select hex8, out of this select entities mask them then the 2D element will appear.

Switch on the arm curve in the model browser to create meshing

We can make 3D elements use of spin option from the 3D menu page first we go to 3D on menu page select spin option and move to spin elements hence we are projecting the elements for 2D elements the angle should be 90 (hit F4 from the functional keys to make a point on circle centre) select base point B and use spin- to create the mesh on arm curve.

3.Create meshing on the Arm Straight by using linear solid

To create the linear solid elements on the arm straight, we need to select the end face of the arm curve to create source face of the arm straight.

To Create source face on the arm straight we need to go to Tools in menu page click the faces option, select arm curve on the component and hit find faces. Hide all components except arm curve geometry and faces to propagate mesh.

Create meshing on the destination face of the arm straight essential to mesh elements as require to propagate.

Then go to linear solid on 3D menu page select source and destination elements on the arm straight. Align the source and destination elements by N1, N2 & N3. Give 12 elements as density in distribute layers and click solids option to create mesh.

Set the current component to arm straight in organize. Select all element in arm straight move to destination component, then go to faces in tools option to delete faces.

Component after creating the arm straight

4.Then go to create mesh on Boss

Create mesh on the surface of the boss in which the elements are to propagate the flow of elements through arm straight.

. Then create a duplicated node on the bottom surface of the boss by using project option on tools menu page.

After creating the duplicate node then go to Solid map option on the 3D menu page.

For creating 3D Hex elements on the boss go through 3D>Solid map>general>change to none on the source geometry>select destination geometry surface>Elems should drag on the surface>select mixed on along the geometry>select all the nodes on node path>Elem size 10mm>Select along the geometry to line>mesh.

Then delete the 2D elements by hiding the arm straight and organize the elements to destination component boss.

Result:

3D mesh is created for the given two solids with tet size of 5mm for housing and hex size of 10mm for arm bracket successfully by following different types of procedures. Checking the tet collapse with 0.15 for housing and proving 0% of failure. Checking the properties of steel rail component in starter file for changing time takes for shock wave to travel the length of the rail (t=0.1927ms) , frequency of animation output to a time for 20 animation steps (Tfreq=0.0096ms) and change N_print as -10 to create new engine file.

Conclusion:

By this assignment I am able to learn about how to create mesh on 3d solids with given specifications, how to check the quality of elements for solids, how to mesh the solids with different procedures, how changing and editing the properties of steel rail component and also knowing the different types of unit system followed in Radioss.

### MESH CLEAN UP ON 2D SHELL ELEMENTS Thulasi Ram Kalichetty · 2020-03-16 17:18:09

PERFORMING MESH CLEAN UP ON 2D SHELL ELEMENTS Objective:                  To be able to create the 2D Mesh with target length of 5mm (Min 3.5mm to max 7.0mm) on given three components foll Read more