Project 2

AIM: 

1.To check for the geometrical errors and clean the geometry for the given assembly.

2. To perform surface and volume mesh(tria mesh) throughout the assembly with the given element quality criteria          below.

  Quality criteria for tria elements(Tyres and Rim): 

 

S.no	Quality criteria	Value
1.	Target length	6.5
2.	Minimum Length	5
3.	Maximum Length	10
4.	Skewness	45

Quality Criteria for mixed elements(for mid surface only):

S.no	Quality criteria	Value
1.	Target Length	4
2.	Min length	2
3.	Max length	6
4.	Aspect	3
5.	Warpage	15
6.	Jacobian	0.7

Quality Criteria for tria elements( other components):

S.no	Quality criteria	Value
1.	Avg. length	4
2.	min length	2
3.	max length	6
4.	skewness	45

Procedure:

1.Importing the CAD model:

1. We import the CAD model of the Rear suspension assembly into the ANSA database using OPEN option in the           File   Tab.

2. we go through mesh module and click on the Length option under parimeter tab to give perimeter and macro             length for better visualization of the CAD model a shown below:

3. We then perform TOPO operation on the whole model which is present under Faces in topo modules and proceed to clean geometry.

2. Geometry cleanup:

We clear all the errors manually going region by region and  we use various operation present in the TOPO modules to get clean geometry as shown below:

 3. Mid surfacing :

1. First we measure the components that are required for creating the mid surfacing using Measure option present under Utilities tab.

2.Then we start taking mid surfacing for following component bracket, circular disc, base plate assembly and conical components.

3. We use the Offset option under the faces tab of the topo modules to take the mid surface of the above components as shown below:

 4. We create different PID's for all the mid surfaced components as shown in the image given below:

 4. Meshing:

1. 2D Meshing:

  In the 2D meshing we will be considering only the above mid surfaced parts and we will mesh it with mixed              elements that include both quad and tria according to quality criteria given in the aim.

2. volume meshing: 

 In The 3D meshing or volume meshing we will be considering the whole volume of the unmeshed components induvidually and we will mesh it with ortho tria and tria elements according to quality criteria.

 We define the material for all the 2D and volume meshed components as shown in the image given below:

 We also assign thickness to the 2D meshed components. Then finally we are done meshing of the components. The final meshed assembly of the rear suspension is shown in image below:

 5.Connection:

 After meshing the suspension assembly we proceed to give connection to the model with the following type of connections.

1. RBE 2 Connections:

 RBE 2 Single Cluster connection

 In this type of RBE2, we provide connection to two or more surfaces which nearer to each other and lock there in all axes and all degree of freedom so that they can't move in any direction. We should go to NASTRAN  module and under Elements tab we select the RBE2 option. we provide these types of connections wherever two or more holes are near to each other as shown in the given below:

2. RBE2 Spider connection: 

In this type of RBE2, we provide connection to one hole which is present on the model to make it rigid in all the axes. We should go to NASTRAN module aqnd under elements tab we select the RBE2 option. We provide these types of connection where are independent holes present a shown in image below:

 3. RBE2 Two node connections:

In this type of RBE2, we provide connection in places like where there are RBE2 cluster connections in the model.We should go to NASTRAN module under Element tab we select RBE2 option and under RBE2 we select the two node option then we select two required nodes to create the connections as shown in image below:

 6. Providing symmetry to the model:

After we finish giving connections, we have to provide symmetry to the model so that the system would look complete. For this , we go to the Transform option in the Utilities tab and we select the entities needed to be given symmetry, on confirmation we have to select Default selected plane so as to get the symmetry. Finally we obtain the complete model as shown in image given below:

 Conclusion:

1. We have check for the geometrical errors and clean geometry for the given assembly.

2. We have perform surface and volume mesh throughout the assembly as per given criteria.

3. we have also assign thickness for the mid surface components after meshing.

4. we have finally also provide connection whereever required for assembly.

Learning Outcomes:

1. Cleaning all the geometry errors for the complex systems.

2. Performing both 2D and volume mesh.

3. Providing connection to all the neccessary axes of the assembly for the complex system.