Project - 2 - Meshing on the suspension Assembly

MESHING ON THE SUSPENSIONS ASSEMBLY

AIM: Meshing on the give suspension assembly according to the given quality criteria and mesh parameters.Use Appropriate connections to connect the suspension assembly and perform Symmetry command to reflect the half finished model to the other side.

PROCEDURE:

STEP 1:

Import the suspension model to ANSA. The file has to be .ansa or .IGS file to import to ANSA software.

"IMAGE 1:Importing the suspension assembly"

STEP 2:

The suspension model which we have consist of three PIDs

1. TYRE.
2. RIM.
3. SUSPENSION SYSTEM.

As per the given first we need to ckeck the geometry of model by using CHECK< geometry option in the TOOLS command.

We need to fix the geometrical errors if thery are any.

"IMAGE 2: Geometry checkup on the model"

STEP 3:

After the geometry clean up we need to set new PIDs for the model.In the given suspension assembly model we are already given with 3 PIDs as i mentioned before.

The Tyer and Rim are already given saparate PIDs but the suspension part of the model has been given as asingle PID so, we now have to use PID region option and assigne new PIDs for each part in the suspension.

we can see the new PIDs in Properties option in LIST command.

"IMAGE 3: Setting new PIDs on the model for different parts "

After the new PIDS are created we have to do some topological clean up by using CUT option and creating new faces by suding NEW option in FACES command in TOPO module on the model.

"IMAGE 4:Topological clean up on the parts of the model "

STEP 4:

For some parts in the model which as the thickness below 5mm and have uniform thickness we have to get the MID SURFACE in order to mesh them. so to get mid surface use OFFSET option in FACES which is in TOPO module.

"IMAGE 5:Midsurface generation of some parts of the model which have uniform thickness less than 5mm "

STEP 5:

As the PIDs for each part is given.Now we have to apply quality criteria and mesh patameters and model the suspension Assembly accordingly.

For assigining the quality criteria and mesh parameters for any model we have to go to UTILITIES command in which we can find the quality criteria and mesh parameters options.

We have been give 3 different qualities for different parts as below.

• Quality Criteria for Surface Meshing of Tyre and Rim (Element type: Tria) :

S.No	Quality Criteria	Value
1	Target/Average length	6.5
2	Minimum Length	5
3	Maximum Length	10
4	Skewness	45

For tyer and rim we have to use volume meshing with tria elements with the above quality criteria.

• Quality criteria for Surface Meshing of Non Uniform thickness components other than Tyre and Rim (Element type: Tria) :

S.No	Quality Criteria	Value
1	Target/Average length	4
2	Minimum Length	2
3	Maximum Length	6
4	Skewness	45

This is a quality needed to be use for parts other than tyer and rim for meshing.

• Quality Criteria for Volume meshing of all Non Uniform thickness components (Element type: Tetra Elements):

S.No	Quality Criteria	Value
1	Tet-collapse	0.2

This is the quality given for volume meshing.

• Quality criteria for Mid surfacing of Uniform thickness part which has thickness less than 5 mm (Element type: Mixed elements) :

S.No	Quality Criteria	Value
1	Target/Average length	4
2	Minimum Length	2
3	Maximum Length	6
4	Aspect	3
5	Warpage	15
6	Skewness	45
7	Jacobian	0.7
8	Minimum Quad Angle	45
9	Maximum Quad Angle	135
10	Minimum Tria Angle	30
11	Maximum Tria Angle	120

This given quality needed to be used to the mid surface only when the thickness is uniform and less than 5 mm.

STEP 6:

After the quality critera and mid surface is assigined. we have to star meshing the model.

First apply the quality given to the tyre and rim then by using spot meshing option in the mesh generation which is in the mesh modules mesh the tyer and rim.select the mesh type as TRIA.

"IMAGE 6:Surfacing 2Dmeshing on the tyer and rim using spot mesh with tria elements "

Use RECONSTRUCT option in SHELL MESH which is in MESH MODULE to improve the mesh quality and get rid of OFF ELEMENTS.

After completing the meshing on the tyer and rim we have to do the volume mesh on them. for that we have to go to VOLUME MESH module.

For foing Volume meshing on any part on the model first we have to define the volume to the part. To define we have to use DEFINE option in VOLUMES which is in VOLUME MESH module.

After the volume is defined.By using TETRA ELEMENTS in UNSTRUCTURED MESH which is in volume mesh module mesh the define parts.

"IMAGE 7:volume meshing on tyer and rim"

Repeat the same process for the Non Uniform thickness components other than Tyre and Rim by appling the given quality .

"IMAGE 8:volume meshing on non uniform parts other than tyer and rim in the model"

For uniform thickness part which has thickness less than 5 mm we have to first oobtain the mid by using offset after that the set the given quality criteria and mesh parameters and then set the element type to mixed in mesh parameters.After all this mesh the midsurface by using spot mesh option.and improve the mesh by using reconstruct option and get rid of off elements.

"IMAGE 9: uniform thickness parts with less than 5mm meshed with mixed elements by creating mid and appling thickness"

STEP 7:

After the meshing on the suspension model is done we haveto connect the parts by using CONNECTIONS by NASTRAN in DECKS MODULE.

Most of the connections in the model are RBE2 connections which can be done by using RBE2 option in ELEMENTs which is in DECKS MODULE. To perform RBE2 connections click on RBE2 and select the nodes in the place where u want to create the conncection and then confirm it and the connection will be created.nodes can be selected in may ways by using NODES OR ENT options in FEATURE SELECTION OPTION.

"IMAGE 10: RBE2 connections on the model "

We also have some parts in which we have to per form the SEAM WELD CONNECTIONS . So to perform seam welding connections we have to first create a curve using the CONS.For creating curves by using cons we have to use CONStoCURVES option in CURVES which is in TOPO module.

Then the curve should be converted to SEAM LINE by using CONVERT option in ASSIEMBLY OPTION.(Assembly<convert<curve<seam line).

After the SEAM LINE is created we have to go to ASSEMBLY<CONNECTIONS<(select the seam line created )<(select the two parts and assigne them SHIFT+? when the seam connections need to be created)<(select OVERLAP SHELL give the different info like distance ,width and assigne different PID.)<and then realize the connection for seam weld connection to be observed.

"IMAGE 11:SEAM WELD connection on the model"

In the suspension assembly ,we have a spring in which PBAR connection need to be created. So fro creatin the CBAR CONNECTION we have to first create a curve by using the CURVE MIDDLE option in CURVES in TOPO MODULE. and connect it by using CONNECT option.

After the curve is created we have to create the CBAR CONNECTION by using CBAR option in ELEMENTs which is in NASTRAN DECKS. NASTRAN DECKS<ELEMENTS<CBAR<select orentation<CURVE(BOX)<(POINT IS CREATED ) <select point < create a new pid<give RADIUS(R) and the PBAR conncection is created.

"IMAGE 12: CBAR connection on the model"

STEP 8:

After all the meshing and connections are completed on the model we have to now REFLECT the model by using SYMMETRY command to finis model to the other side.

To perform symmetry first go to UTILITIES< TRANSFORM<COPY(entites)<SYMMETRY<(give 3 coordinates) and press finished to get the reflection of the model other side.

"IMAGE 13:final model after symmetry"

LEARNING OUTCOMES:

• Learned how to import the model to ansa.
• Learned how to do geometry check by using check geometry option in tools.
• Learned how to give new PIDs.
• Learned how to do topological clean up by using options like cut and new in faces.
• Learned how to apply quality criteria and mesh parameters to any model.
• Learned how to do meshing both mixed and tria by using spot mesh in mesh module.
• Learned how to improve the mesh by using reconstruct and smooth option in mesh module.
• Learned how to do volume meshing by using tetra elements.
• Learned how to define a volume to any part in any model.
• Learned how to do mid surfacing by using offset
• Learned how to assigne thickness to the mid surface.
• Learned how to do connections like RBE2 and seam weld connections.
• Learned how to do PBAR connection.
• Learned how to reflect the model by using symmetry option.

CONCLUSION:

Finally,Meshing on the give suspension assembly according to the given quality criteria and mesh parameters.Use Appropriate connections to connect the suspension assembly and perform Symmetry command to reflect the half finished model to the other side is done.

DRIVE LINK:

https://drive.google.com/file/d/1U0R2o6ppFHzEzQNGf3e0TYCFMKhK5Nwn/view?usp=sharing