CREATE 1-D CONNECTIONS FOR REAR DOOR OF THE CAR

                                    

 AIM:

    To perform connection's for a given FE model of the car with different connection technique's by using NASTRAN

 

 THEORY:

    REAR DOOR:

      A car door is a type of door typically hinged, but sometimes attached by other mechanisms, guide rails etc.. the door is used for entering and exiting a vehicle . the vehicle door is open to provide access to the opening or closed to secure it.  

    NASTRAN DECK:

      NASTRAN is a finite element analysis program that was originally developed form NASA in 1960.

    CONNECTIONS:

      Connections that are used to connect the two parts of the system

      i.e Rigid body connections 

      RBE2 by many nodes

      RBE2 by two nodes 

      RBE2 by single node

 

 PROCEDURE:

    STEP 1: IMPORT FE MODEL TO ANSA

    STEP 2: ASSIGNING DIFFERENT PID

    STEP 3: CONNECTIONS

    STEP 4: MANUAL METHOD OF CONNECTIONS

    STEP 5: WELD JOINTS

    STEP 6: DOOR HANDLE CONNECTIONS

    STEP 7: WINDOWS CONNECTIONS

    STEP 8: PROPER ALIGNING OF CO-ORDINATES 

 

      STEP 1: IMPORT FE MODEL TO ANSA

          Import the given FE model into ansa 

          FILE<<INPUT<<NASTRAN

    

      STEP 2: ASSIGNING NEW PID

          Assign a seperate PID's for each part of the given FE model 

    

      STEP 3: CONNECTIONS

          Check the holes area that where the bolts connections has to made visualize the parts first then by using COG under points create a COG and covert that COG point to bolt after conversion give connections by auto method 

          GOTO TOPO MODE >> POINTS>> COG >> OK 

          Convert command is on top in assembly panel 

          CONVERT>>COG POINT>>BOLT>>OK

          Then goto connection manager 

          CONNECTION MANAGER>>SELECT BOLT>>SELECT THE PARTS TO DO CONNECTIONS >> SELECT FEP REP>> BOLT>> GIVE SEARCH DISTANCE>> APPLY > REALIZE

    

                                                                                   CREATE COG 

    

                                                                      CONVERTING COG POINT TO BOLT

    

    

                                                                           CONVERTED INTO BOLT

    

                                                                         ASSIGNING P1 AND P2

    

                                                          FINAL CONNECTION OF BOLT BY AUTO METHOD

    

    This is auto method in this method the maximum of 4 parts can be connected.

 

      STEP 4: MANUAL METHOD OF GIVING CONNECTIONS

          Here first visualize the bolts parts and where to give rigid connection and all 

          Then by using RBE2 under NASTRAN deck select the nodes in the hole or connection region 

          Select RBE2 by many node or

          Select RBE2 by single node for node selection.

          RBE2 by many nodes :

                 Select the nodes by loop selection then click ok cluster formation of connection will be formed as shown in below fig 

    

                                                                        CLUSTER CONNECTION

    

     ELEMENTS>>RBE2 MANY NODE >> SELECT SLAVE NODES>> SELECT MASTER NODES>>OK

 

     RBE2 by two nodes selection: 

         In this type we use to connect to rigid elements by using two-node RBE2

         First select nodes and create rigid connection and do same to another hole region 

         After giving connection use RBE2 two nodes connection select master nodes 1 and 2 and connect those with 2 nodes RBE2 connection

         ELEMENT>>SELECT ONE MASTER NODE >> SELECT ANOTHER MASTER NODE >> OK

    

                                                       SELECTION OF FIRST AND SECOND MASTER NODE

    

                                                                     TWO NODE RBE2 IS CREATED 

      STEP 5: WELD JOINTS

          Weld joints data are generally given suppose if its not mention any data in such cases the weld connections can be given as per geometry design by visualising

          For this first GOTO TOPO MODE>>POINTS>>COG>>SELECT AN ENTITIES BY MESH BOX>>COG IS GENERETED>>CONVERT THE COG BY SELECTING 3D POINTS>>SPOT WELD>>DESFINE CONNECTIONS>>SELECT FE REP>>RBE3-HEXA-RBE3>>ENTER SEARCH DISTANCE>> RBE3 PIN FLAG 123456>>OK

          123456 degree of freedom it means that the weld is fixed constraint in all the direction of movements.

    

                                                                               BOX SELECTION

    

                                                                                 COG CREATED

    

                                                                          SPOT WELD SELECTION

    

    

                                                                          CONNECTION MANAGER

    

                                                                          DETAILS OF SPOT WELD 

    

                                                                           ASSIGNING P1 AND P2

    

                                                                           SPOT WELD GENERATED

 

      STEP 6: DOOR HANDLE CONNECTION

          Door handle part is mass containing so here we need give rigid connections to two holes then again we need to connect those master nodes by using RBE2 two nodes after connecting those two master nodes . one center node will form at the mid of the handle there we need to give mass connection by using CONMI 2

          To give the mass following procedure to be used  

          GOTO NASTRAN>>ELEMENTS>>CONMI>>CONMI2>>NODES>>NEW PROPERTY TAB WILL OPEN>>GIVE MASS VALUE (mass in tonnes 1000=0.001)>>OK

    

                                                                NODES FORMATION AT FIRST HOLE

    

                                                                RIGID CONNECTION AT FIRST NODE 

    

                                                             NODE FORMATION ON SECOND HOLE

    

                                                             CONNECTING TWO MASTER NODES 

    

                                                                 APPLYING MASS AT THE MID NODE

    

                                                             MASS IS GENERATED AT MID OF HANDLE

 

      STEP 7: WINDOWS CONNECTION

          To perform connection to the window parts there is some procedure to be followed

          First create curve on windows border by using FEAT 2 CURVE under mesh mode 

          MESH MODE>>PERIMETER MODULES>>FEAT 2 CURVES>>CREATE A CURVE BY SELECTING ENTITIES

    

    

                                                              CREATE NEW PART IN MODEL BROWSER

    

                                                                               CURVES CREATED

      

      After creating a curve 

      Convert curve to spot line 

      GOTO CONVERT>>SELECT CURVE>> SPOT LINE

    

    

                                                        SELECTING CURVE TO CONVERT SPOT LINE

    

    

                                                                             SPOT LINE CREATED 

      After creating a spot line 

      GOTO CONNECTION MANAGER>>SELECT THE SPOT LINE>>ASSIGN P1 AND P2 >>SELECT FE REP>> RBE3-CBUSH-RBE3>>GIVE SEARCH DISTANCE 50>>ENABLE (keep all branches)>> CREATE NEW PID(CONTROL+SHIFT+?)>>NEW WINDOW OPENS>>CREATE NEW PART ID>> DOUBLE CLICK>>APPLY REALIZE

    

                                                                         CONNECTION MANAGER

    

                                              ASSIGNING P1 AND P2 AND FE REP AS RBE3-CBUSH-RBE3 

    

                                                                            CBUSH GENERATED 

    

                                                                  FINAL CONNECTION OF CBUSH 

 

      STEP 8: PROPER ALIGNING OF CO-ORDINATES

          Once the connection is done the alignment is to be made according to global co-ordinate to make stable.

          GOTO DATABASE LEFT SCREEN>>SELECT ELEMENTS>>OPEN CBUSH>>ENABLE ORIENT>>SELECT ALL THE ELEMENTS OF CBUSH>>RIGHT CLICK>>MODIFY>>ORIENT WITH CORD>>CID=0>>OK

    

                                                                            ENABLING ORIENT

    

                                                                               MODIFYING 

    

    

                                                  FINAL ALIGNED ACCORDING TO GLOBAL CO-ORDINATE

 

      RESULT: THE CONNECTIONS HAS BEEN MADE TO THE GIVEN FE REAR DOOR MODEL 

    

    

                                                  FINAL CONNECTIONS HAS DONE FORGIVEN MODEL

   

      LEARNING OUTCOMES:

1. Learned how to import the NAS, file into ANSA.
2. Learned how to assign the different PID's for door model.
3. Learned how to make connections of bolt by using RBE2 by many nodes,RBE2 by two nodes'
4. Learned how to create a bolt by auto method.
5. Learned how to visualise the weld spot where the data is not given.
6. Learned how to give weld connection.
7. Learned how to apply mass by using CONMI.
8. Learned how to make windows connections by using RBE3-CBUSH-RBE3.

    

      CONCLUSION:

              The given car rear model is done with connections here visualizing the parts where to weld and where to give connection is very much important before giving the connection first we need to visualize and the model is ready with all connection .