Week 9 - Creating connection for Rear door
OBJECTIVE:
To perform suitable connections between various parts/components in the side door FE model provided, after creating and applying different PIDs to the mentioned components that are parts of the model.
FE Model:
PROCEDURE:
1. Firstly, in order to set up the more complex connections for the challenge, it is important to differentiate components as the connections may require different PIDs. This entails the first step. The entire model will be separated into different PIDs. This requires creating said PIDs and that can be done via Classic mesh - Macros - Set PID .
2. We can start off with RBE2 connections. The RBE2 tool can be accessed via Elements > RBE2 in the NASTRAN deck. It primarily has the 'many nodes' and 'two nodes' options. In the following example, we deploy the 'many nodes' option to connect two holes with a single master node. This is merely done by selecting the two sets of nodes surrounding the holes and letting the algorithm create a master node and form connections by running through the straightforward process. This is also known as a cluster node RBE2
Then there is the two-node RBE2 process. This involves connecting two sets of RBE2 spiders using a double con. The RBE2 component is created separately for each hole using the Elements > RBE2 > Many Nodes option discussed before. Through this process, we'll have two master nodes (which are to be connected). To connect them, we shall be using the Elements > RBE2 > Two Nodes tool. Then it is just a matter of selecting the two master nodes to form the connection. This is typically used in cases where assigning properties for the bolt stem might be a requirement.
There is another way to assign bolt connections which becomes especially useful in cases where there are more than 2 layers that require connecting. This will involve using the connections manager. Before that, we need to create a COG point in one of the holes from a layer in the middle (using the Points > on COG tool from the topo deck)
Then the point needs to be converted into a bolt using the convert tool from the upper toolbar (selecting 3D points).
After converting the point into a bolt, the connection manager is accessed and the bolt point selected. Clicking the middle mouse brings up a set of options that needs to be edited in order to develop the proper bolt connection.
In the set of options, the sections P1, P2 & P3 need to be assigned (since there are three layers). The part on the same plane as that of the bolt point would be P1 and the others can be assigned interchangeably. To select the PIDs for each, right-click on the option (P1, P2 or P3). A box pops up. There, we need to press F1. This will let us select the particular PID.
3. Now onto the door handle. In this region, we need to create a connection , For this, we need to create RBE2 nodes in either handle holes separately (using Elements > RBE2 > Many Nodes)
Again, using the same tool, the two master nodes for either handle hole is selected and another connection is created, with the algorithm assigning a new master node at the centre of this connection.
Now, we make use of the Con Mass tool, accessible through Elements > CONMi > CONM2 > Nodes. Then the previously mentioned master node is selected. This is where the mass of the handle will be concentrated. After proceeding, the algorithm lets us assign the mass ('M' in tonnes).
For spot welds, we shall be making use of the COG tool again to create 3D points. These 3D points are then converted into 'spot welds'.
After conversion, it's the same process of accessing the connections manager and assigning properties. This time, since it's a spot weld, the FE Rep Type would be RBE3-HEXA-RBE3. A suitable search distance is assigned. P1 would be the same component on which the spotweld point is situated and P2 would be the layer below.
3. The last type of connection involved in this challenge would be that of CBUSH RBE3 elements, which will be used wherever window weather strips (seals used to keep interior air in and external elements out) are involved.
To begin, the perimeter of the glass components is used to create curves. For this, Perimeters > Feat2Curve tool is used to select and create them. These created curves are then used to create a single set of offset copies. This is considering connection requires setting up on either side of the glass. We can make use of the Transform > Copy tool for this. A distance of 5 mm should be adequate:
After converting them, we avail the help of the connections manager again to create these CBUSH connections. The process will be repeated for each curve.
For the options, we will need to select the P1, P2 (& P3 if needed) as usual. But here, spacing (S) needs to be specified (10mm). The FE Rep type would be RBE3-CBUSH-RBE3.
FINAL MODEL:
CONCLUSION:
Suitable connections were deployed between various components in the side door model after PIDs were assigned to each component.