Connections Implementation For The Rear Door

Implementation Of Connections For The Rear Door

Aim: To create the connections on rear door by using connection techniques in ANSA.

Procedure:

1.Import Rear Door.NAS in to the ANSA: Import the given Rear Door.NAS in to the ANSA Shown in the fig.1.1. For Importing NAS type we have to use input option (File>Input>NASTRAN).

Fig.1.1: Imported File

A. Before starting connection make sure that the model should be meshed and all type of the connections are mentioned. Check the type connections such as Bolt connections, spot weld, seam weld, damping connections and etc.

B. In ANSA every connection has degrees of freedom and numbered as 1,2,3,4,5&6. Every number associated with particular direction shown in the table 1.1.

Sl.No	Axis	Direction Of Movement
1	X-1	Translational along +X,-X
2	Y-2	Translational along +Y,-Y
3	Z-3	Translational along +Z,-Z
4	X-4	Rotation X
5	Y-5	Rotation Y
6	Z-6	Rotation Z

Table 1.1.

2. Create The Connections:

Following types of connections are made on rear door.

A. Bolt Connection:In bolt connection we are joining 2 or 3 parts together for making rigid connections using NASTRAN deck. In ANSA NASTRAN deck bolt connection can be achieved by three methods.

1.RBE2 (rigid body element of form 2) With stem (shank): Here connection is made for 2 or 3 holes by making separate RBE2 many nodes (NASTRAN>ELEMENTs>RBE2>Many Nodes) for all holes.And connecting all with the help of stem by RBE2 two nodes (NASTRAN>ELEMENTs>RBE2>Two Nodes) shown in the fig1.2.

Fig.1.1: Bold Connection.

While Using RBE2 new window pop up for selection of nodes or elements click next and another window will pop up there we can see details such as element ID, Grid Point, degrees of freedom etc. The nodes which are on hole perimeter are called slave nodes and middle node is called masted node. 2 master nodes are joined by stem.

2.RBE2 (rigid body element of form 2) Without stem (shank): It is similar the first method but we are selecting all nodes from different holes together to make single master node. here stem of bolt is not available. shown in the fig.2.1.

Fig.2.1: Bold Connection.

3.Automated Connection: In Automated first we have to create 3D point on hole by using TOPO>Points>On COG>Edges. convert 3D point to connection type as a Bolt in MENUBAR>Assembly>Convert while converting it will ask for type, select 3D points type and select point again it will ask for type of connection select as bolt and press ok . by using connection manager we can generate bolt connection shown in the fig.3.1.

Fig.3.1: Connection Manager

Similarly all bolt connections are made. In degrees of freedom we can remove constraint by delecting numbers from 123456 depending on the direction refer table 1.1.

B. Spot weld Connection: It is a type of electric resistance welding used to weld various sheet metal products, through a process in which contacting metal surface points are joined by the heat obtained from resistance to electric current.

We have to create 3D point on hole by using TOPO>Points>On COG>Edges. convert 3D point to connection type as a Bolt in MENUBAR>Assembly>Convert while converting it will ask for type, select 3D points type and select point again it will ask for type of connection select as Spot weld point and press OK. Next step is select the connection manager, select for P1 and P2, search distance weld FE type is RBE3-HEXA-RBE3. constraint all DOF by entering the 123456. set PID for spot weld, apply and realize shown in the fig4.1.

Fig.4.1: Connection Manager

In spot weld we can see the master nodes are formed by single slave nodes and it is formed by Hexa FE elements shown in the fig.4.2.

Fig.4.2: Spot Weld

C. Damping Connections or CBUSH: For car door glass border we have to make damping connection. to make that convert FE line to curves (ESH>Perimeters>Feat2Curve) and convert curves as Spot line.

From connection manager the following steps to follow to acheive connection.

1. Open connection manager and select spot line middle mouse click new window pop up.

2. Select the P1 & P2 and the value for 'S' is 10 witch is Space between each CBUSH

3. IN right side select the type of FE is RBE3-CBUSH-RBE3 and enter search distance

4. In inter face keep all branches as mark and set PID by pressing 'SHIFT+?' in key bord and enter 6 stiffness values (Stiffness is the extent to which an object resists deformation in response to an applied force. The more flexible an object is, the less stiff it is)

5. Apply and realize. the fig5.1 shows connection manager and connections.

6. CBUSH is in local coordinates but we have to change it in to global coordinates. To change this in CBUSH PID change CID no to '0' and Orient to 'With Cord' for all CBUSH PID shown in Fig 5.2.

Fig.5.1: CBUSH Connection.

Fig.5.: Local To Global

D. Other Connections: To make door handel connection We can use RBE2 many nodes to make one set on RBE2 and join 2 master nodes by using RBE2 and assign mass (NASTRAN>ELEMENTs>CONMi>CONM2>nodes) to the 3rd master node which is formed from first 2 master nodes. Mass must be in tons 100grams = 0.0001 tons. shown in the fig.5.3. and fig 5.4 shows the connection.

Fig.5.3: Assign Mass

Fig.5.4: Door Handel Connection

Learning Outcome:

1. Learnt user inter face of ANSA for NASTRAN deck
2. Learnt making connections such as Bolt connections, spot weld, seam weld, damping connections and etc.

Conclusion:

Connections are done successfully for a Rear Door model by using ANSA for NASTRAN deck.