Week 6

WEEK 6 CHALLENGE : REAR DOOR

Aim:

To use different types of connection techniques and implement on the given rear door model.

Procedure:

• Import the FE model to the ANSA Work Bench.
• Study the model in terms of geometry and mechanism.
• Connection of Latches and hinges.
• Connection of Bolts and Nuts.
• Connection of Weldings.
• Connection of Window Glass.
• Connection of Door Handle.

Step 1:

Import the Door FE model into the ANSA Work Bench :

• Open the Door FE Model in the ANSA Work Bench.

Step 2:

Study the model in terms of geometry and mechanism.

Get to know the model inside out and the wroking of different mechanisms so as to get an idea on where to rigidise and connect using different connection techniques.

Step 3:

Connection of Latches and hinges .

• Connect the overlapping Hinge areas through RBE2 Cluster Element by selecting the Perimeter Nodes.

NASTRAN DECK > ELEMENTS > RBE2 > MANY NODES

• Now, the Cluster RBE2 Element is created and the rotating link has to be connected using two Node RBE2 Element.

NASTRAN DECK > ELEMENTS > RBE2 > TWO NODES

• In the Property Tab , give the value of DOF as 12345 as the hinge is constrained in all direction except the Rotational Z axis as the door needs to be opened and closed.

Step 4:

Connection of Bolts and Nuts

• Now do the connections for all the Nuts and Bolts .
• Bolt Representaion can be done manually as explained in step 3 by using Cluster RBE2 or 2 Node RBE2.
• The connections of bolts and nuts can be shown using auto mode.

• Identify the Bolt and Nut Area and create a 3D point on the Bolt hole.

TOPO MODE > POINTS > ON COG

• Convert the 3D points into the Bolts .

ASSEMBLY MANAGER > CONVERT > 3D POINTS > BOLTS

• The 3D points that has been converted to Bolts will be represented as shown in figure below.

• The 3D points that has been converted to Bolts will be represented as shown in figure.
• Now, click on the Connection Manager and select the Bolt .
• Select FE rep Type as Bolt and Assign P1,P2 and P3 surfaces respectively for which the connection is required.
• Assign Search Distance as 20 and Body type as RBE2.
• After filling the required data, click Apply and Realize the Connection.Thus the Bolts Connection has been created as shown in figure .

Step 5 :

Connection of Welds

• To represent a Spot weld first create a 3D Point as explained above.
• Once the point has been created, convert the point to spot weld as shown in the Figure

• Now Open the Connection Manager and Select the Spot Welding Points.
• Select P1 and P2 for which the spot weldings have to be done.
• In the FE Rep Type, Select RB3-HEXA-RB3 for the spot welding.
• Fill the required data Click on Apply and Realise, the spot weld is represented as shown in figure.

Step 6 :

Connection of Window Glass

• Create the Feat2Curve around the Window Glass as shown in the Figure below.

MESH MODE > PERIMETER > FEAT 2 CURVE

• Convert the Curve to the Seam Lines.

ASSEMBLY MANAGER > CONVERT > CURVE > SEAM LINE

• Now, go to the Connection Manager and select the spot lines for which the connecton has to be made.
• Fill all the required data such as FE Rep Type:RB3-CBUSH-RB3,Search Dst:50 and Assign New PID.
• Select the P1 and P2 for which the C Bush connection is required and also mention the distance between the two CBUSH which is represented as "S" in Connection Manager.
• In the connection interface, enable Keep All Branches .

• Click on Apply and Realize. C BUSH connection is created as per the requirement as shown in fig.
• For the opposite side, transform the curve at distance of 10 and follow the same procedure.

Step 7 :

Connection of Door Handle

• Initially, Rigidise the two Ends of the handle using Many Nodes RBE2.

ELEMENTS > RBE2 > MANY NODES

• Now,connect those rigidised RBE2 Elements with Two Nodes RBE2 element as shown in the figure.

• Once the Handle is rigidised, assign approximate Mass value for the handle at the centre of the 2 Node RBE2.

NASTRAN DECK > ELEMENTS > CONMi > CONM2 > SELECT THE NODES

• In the Mass coloumn, enter the Mass Value (M) and Click OK.
• Thus, the mass has been assigned to the Door Handle.

Learning Outcomes:

• Understanding the Mechanism of the Car Door.
• Types of Connections.
• Representation of Spot Welding and Bolt/Nut Connection.
• Degrees of Freedom and its importance in NVH Analysis

Conclusion:

• Connections of rigid body.
• Degrees of freedom contrained for hinges.
• connections for spot welding are done.
• Cbush elements are represented.
• Mass for the handle is represented.

Google Drive Link :

https://drive.google.com/file/d/1gQZ0TQ-QcF0nf_Ea8nHnrJpAXxBt5h9F/view?usp=sharing