Connections deployment in Car door

Aim-: To deploy the connections between different FE elements accordingly.

Procedure-: To properly connect the surface we should have the CAD data and the FE model of the same part.

• To start the connections, first, we need to mesh the geometry of the desired model.

• After cleaning up the topological errors, we need to obtain the mid surface of the geometry.

• To obtain the mid surface, there are two paths. 1. Use the mid surface option in ANSA 2. Obtain the mid surface manually.

• If we use the automated mid surface option we can use different techniques depending upon the geometry.

• Before starting with the automated mesh generation option, first, we need to give the quality criteria for the mesh in mesh parameters and QC tab.

• But in this, we already have a FE model on which we need to deploy the connections.

• Before deploying the connections, it\'s a good practice to have a backup CAD geometry data.

• In this door model, we will be deploying the connections in the hinge, glass actuation mechanism, and windshield closing line.

• To start the connections, we should be working under the NASTRAN deck in the ANSA.

• Under the NASTRAN deck, we will be using RBE2 elements which are used as rigid link connections.

• After opening the FE model under the NASTRAN deck, the first connection we work on is the hinge mechanism that connects the door with the body of the car.

• To connect the hinge holes, first identify the holes and create 3-D points using the topo deck.

• After creating the 3-D points for the hinge mechanism holes, we need to define the connections as bolts. It can be done in two ways.

• The first way is to make ANSA identify the connection as a rigid link, second is directly making the connection as a rigid link using the RB3 element.

• To make ANSA realize the connections as a bolt rigid link, we use connections manager to convert the created 3-D points into bolts.

• After converting those points into bolts, we need to realize the connection. To make realize the connection, we use connections manager.

• Select the point from the connections manager and select where it needs to be deployed. After realizing the connection, these nodes have to be aligned with respect to the global coordinate system rather than local.

• To change the orientation according to the global coordinate system, open the database browser and select the doorline part.

• Select show/hide columns option, search for orient option and click on it to make that column visible, add CID and give 0 as input.

• To deploy the same connection manually, select the RBE2 element from the NASTRAN deck and select the nodes around which the rigid link has to be deployed. This connection type is the same we did in the automated realization of the bolt rigid link connection.

• After doing the connection of hinge, we need to give the z-axis orientation, for that click ion the info under elements tab and click on the MASTER node then a dialogue box appears.

• In that dialogue box, there is an option where it shows numbers like 123456, which means this rigid link is constrained in all 6 degrees of freedom in which the first three numbers represent translation DOF of three axes X, Y & Z respectively. The last three represent the rotational DOF.

• The hinge mechanism has to be rotating about the axis-z we need to release the z-axis rotational constraint. To provide z-axis rotation, remove the number 6 from the dialogue box.

• In the same way, as above deploy the bolt connections as rigid RBE2 elements wherever necessary.

• While connecting the windshield with the body of the door, we use RBE3-CBUSH-RBE3, before connecting, the door line has to be created.

• This doorline can be created by using the feature to curve option in the meshing deck, after creating the curve around the windshield, convert them to a seamline using connections manager.

• After converting them to seamline, select the seamline from the connections manager and select the parts to be connected.

• After selecting the parts, FE has to be represented using the RBE3-CBUSH-RBE3 element and give search distance accordingly.

• Click on apply and then realize the connections. One can give the stiffness values for the same element accordingly.

• The door latch mechanism is connected as a rigid link and a concentrated mass has been given to at the master node for both elements.

RESULT:- Representing the rigid links as bolts and some other complex connections as and underlying tweaks such as DOF and stiffness values has been learned.