DEPLOYING CONNECTIONS TO AN AUTOMOBILE REARDOOR USING ANSA

DEPLOYING CONNECTIONS TO AN AUTOMOBILE REAR DOOR USING ANSA

AIM:-

1) To provide connections for the rear door model.

2) Explain about the Different connections given for the model.

PROCEDURE:-

1)IMPORTING THE FILE:-

We  First import the model using the NASTRAN option present in Input option of the File Menu, Since the model is in .nas format which NASTRAN solver Format on opening the model we find that the model is in Single PID.

                                             FIG 1. Given FE Model.

2) Setting up PIDs for Rear Door:-

    We set the PIDs for the rear model using  PID region and SET PID option in the Faces section of the Topo module.

                           FIG 2. Rear Door Model ( After Setting PIDs )

3) Connections :-

RBE2 Connections :-

1) RBE2 Spider Connections :-

      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 and under elements tab we select RBE2 option. We provide the type of Connection Where there are independent holes present in the model as shown in the Figure given below.

                                                 FIG 3. RBE2 Spider Connection.

2) RBE2 Two node Connections :-

In this type of RBE2, We provide connections in places like Where there are Door hinges Present in the model.We should go to NASTRAN module and under elements tab, We select the RBE2 option and under RBE2 we select the Two node option . Then we select the two required nodes to create a coonection as shown in the figure given below.

                                                             FIG 4. RBE2 Two node connections ( Door Hinges )

After that we go to elements tab and select the Info option , we select the two node connection created and we get the information of the connection in that ,we lock the degree of freedom i.e. CM to only 5 axes, so that the movement of the door can only occur in the 6th axes.

                                                   FIG 5. Door Hinges ( locking the degree of freedom to only 5 axes )

3) RBE2 Single Cluster Coonections :-

        In this type of RBE2, we provide coonection to two (or ) more holes on two ( or ) more surfaces which are nearer to each other and lock them in all axes and all degree of freedom ,so that they cant move in any direction , we should go to NASTRAN module and under elements tab , we select the RBE2 option we provide the type of connection wherever there are two ( or ) more holes nearer to each other in rear door as shown in figure below.

                                                         FIG 6. RBE2 Single Cluster Coonections.

4) RBE2 Coonections For Door Handle :-

In this type of RBE2, we provide Coonection in the Door handle by Providing the spider coonection of two holes of the door handle and then connecting the master nodes of the two spider connections to form a centroid ( or)  COG as shown in the Figure below.Then we provide the Con mass for the COG point using the Nodes option present in the CONM2 in the CONMi option in the elements tab of the   module.Then in that tab we provide the COG mass as 100 gm , we provide values of mass in tonnes i.e. 100 gm = 1e^-4 tonnes in that tab as shown in the figures given below.

                                                          FIG 7. RBE2 connections for Door Handle 

                                                     Fig 8. Assigning Mass to the Door Handle 

Bolt Connections:-

In this type of connection,we provide connection to wherever the bolts are going to be fitted in the rear door model i.e. near to attaching hinges in this case we first create a 3D point near the holes of the bolt Connection using the ON COG option point in the Points tab of the Topo Module.Then we convert the 3D points into Bolt washer point using Convert option present in the Assembly tab as as shown in the figure given below.

                                                                FIG 9. Bolt Connection ( converting 3d point into Bolt )

After that, we go to Connection Manager,option present in the assembly tab and select on the washer point and then we press middle mouse button to get the connection manager tab , we have 3 tabs in the Connection Manager menu namely Connectivity list,Connection list and FE representation settings.We go to the Connection  list  and we proceed to give connection for which all parts we want using F1 tab ,we go to the model and we select each and every part,then we provide the zones to be attached as In/out , we apply all settings and click on realize option.The connection manager tab is shown in the figure given below.We finally obtain the bolt connection in which all the nodes nearing to the boundary of the bolt Coonections are connected using RBE2.

                                                           FIG 10. Bolt Connection ( Connection Manager ) 

                                                              FIG 11. Bolt Connection.

Spot Weld Connections :-

In this type of Connections , We provide connections to whenever the spot weldings are going to be done in the rear door model.We first create a 3D point near the weldings area using the on COG option present in the points tab of the TOPO module. Then we convert the 3D points into Spot weld points using Convert option present in the Assembly tab as shown in the figure given below.

                                                       FIG 12.Spot weld Connection ( Converting 3D point into Spotweld point )

After that , we go to the connection manager option present in the assembly tab and select on all the spot weld points and then we press middle mouse button to get the connection Manager tab.we have 3 tabs in the Connection manager menu namely Connectivity list,connection list and FE representation sttings,we go to the coonection list and we proceed to give coonection for which all parts we want using F1 tab, we go to the model and we select each and every part and press enter to confirm,we provide the Fe representation type as RBE3-HEXA-RBE3,and then we provide the value of search distance,after that we lock the spotweld in all axes i.e. 123456 using the RBE3 pin flags option and finally we create a SOLID PID to represent the spot weld . we apply all the settings and click on realize option.The connection manager tab is shown in the figure given below.

                                        FIG 13. Spot weld Connection ( Connection Manager )

                                                       FIG 14. Spot weld Connection.

Window Bushing Connection :-

In this type of connections,we provide connections to the window with the help of bushes so that the window doesnot break using the NASTRAN simulation of the rear door. First,we take curves from the windows using the FEAT 2 CURVE Option present in the Perimeters tab of the Mesh module.then,we convert the formed curves into spotlines using the convert option present in the Assembly tab as shown in the figure given below.

                                             FIG 15. Bushing Connection ( After creating curves using FEAT 2 CURVE option )

                                             FIG 16. Bush Connection ( Converting curve into Spotline )

we,then go to the connection manager to provide connect data . we have 3 tabs in the connection manager menu namely Connectivity list,Connection list and FE representation settings.we go to the Connection list and we proceed to give connection for which all parts using F1 tab,we go to the model and we select and each and every part and press enter to confirm, we go to the FE representation type and provide it as RBE3-CBUSH-RBE3, In that , we provide the search distance ,we also tick in the check box of the keep all branches,so that we can visualize spotline even after realizing it ,we then provide the 6 different stiffness constant to the bush.Finally we click on apply and realize.the figures of Bush id and Connection manager as given below.

                                                        FIG 17. Bushing Connection ( Connection Manager )

                                                    FIG 18. Bushing connection ( stiffness constant )

After that,we go to the CBush elements and see that all the CBush elements are oriented with respect to the vector direction Therefore we change it with respect to the local co-ordinate system by right click on all the Cbush elements and then give modify after it a new tab opens and we go for new modification using modification rules where we provide orient as the modification and align it with respect to the co-ordinate,then give the co-ordinate point as 0.and then give ok. we obtain all the CBush elemnts aligned in the same co-ordinate sysyem according to the local co-ordinate system.The figures are given below.Finally we obtain the CBush elements as shown in the figure given below.

Fig 19. Bushing Connection ( C Bush elements are aligned in the same co-ordinate system according to local co-ordinate system )

                                                       Fig 20. Bushing Connection

Conclusion :-

we obtain connections for the whole rear door model which include RBE2 connections ,Bolt connections ,spot weld connections, and window bush connections. The final connected finished model is shown in the figure given below.

                                           FIG 21. Final model ( After Deploying Connections )

Learning outcomes :-

Ability to give connections to Complex models like Rear door , which include RBE2 Connections,Bolt Connections,Spot weld Connections and window bush connections using the NASTRAN module.