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 .