Week 6 - Creating connection for Rear door

• AIM : -

Creating 1D Connection using NASTRAN deck for given rear door of car FE model.

• Objective :-

* Creat and apply different PID's for different components.

* Perform suitable connection using 1D element for given model.

• Procedure : -

import the model :

* First we import the model in ANSA ( File - open - select file - ok )

Segregate the model according to PID's :

* The given model has only one PID , so in order to given connection and realize them we have to segragate model into different PIDs according to components.

* For this task we use set PID tool to create PIDs for components. ( mesh - macros - set PID ).

* we use PID region selection tool for this operation.

Creating connections :

* First create the bolt connection.

* We check and observe the model and decide where we do bolt connection.

* The hinge part is important part connected with the outer surface of the rear door connection with the outer body of the vehicle has given the rigid connection of bolt as RBE2 element.

* there are servel ways to present the bolts.

- by creating RBE2 cluster .

* in this metod we creat RBE2 elements in b/w 2 more holes.

* we select node of hole by loop selection and create cluster .( NASTRAN deck - elements - RBE2 - many nodes ).

* we are the creation of bolt cluster.

- by creation RBE2 spider in each hole and b/w them 2 node RBE2 elements.

* in this method we create a spider of RBE2 elements in each hole . ( NASTRAN deck - elements - RBE2 - many nodes ).

* after that we create a two node RBE2 elements b/w the spider of hole which acts as a bolt body ( NASTRAN DECK - elements - RBE2 - two nodes ).

* in below image we can see that the bolt is create.

- Automatic bolt creating through 3D point.

* in this method first we create the COG point in any one hole. ( topo - points -COG - egdes ).

* after this convert this 3D points to bolt by convert tool . ( assembly - convert - select points - bolt ).

* then we go to connection manger and select this bolt symbol and open connection manager.

* First we select parts by right click on p1 and then left click on box and then click on F1 and select points.

* after this we select the FE rep type as bolt and give search distance.

* afteFr this we select zones and click on apply and realize.

* in this connection we select inner zones but we can also select in/out or other option.

providing CM ( degree of freedom ) for opening the door :

* the door is moving part of the vehicle body and in simulation process it act as a car door open and in required direction.to have a correct connection to the hinge part which connection the door with vehicle , we have to provided Z -axis rotational movement by removing DOF of this RBE2 elements.

for door handle :

* in this region we need to create a connection that appiled a mass ( to represented the handle ) for this we need to create RBE2 cluster in each handle hole separately (NAATRAN DESK - element - RBE2 - many nodes ). After that we create a 2 node RBE2 elements b/w these 2 nodes. due to this a master node is created.

* for apply mass we use to the nastran deck and in element we use CONMI - CONM2 - NODES Then the previously mantioned master node is selected. this ie where the mass of the handle wii be concentrated

* after bolts we create welds connection ( Seam weld and spot weld ).

* we observe the model and check where we can use seam weld and where and spot weld.

for seam weld

* there are two types of seam weld

- 1st is overlap shell joint - used when parts are parallel to each other.

- 2nd is y- joint shell - used when parts are perpendiculer or inclined.

*we can also used seam weld with RBE2 ELEMENT.

* For generating the weld date we create curves from FE model (mesh desk - perimeter - feat2curve ).

* then we convert this curve to seam line by convert tool.( assembly - convert - curves - seam line ).

* after the conversion of curve we proceed to create seam weld for this go to connection manager and select this created seam line and open connection manager after this we select parts and then select the FE rep type as overlap shell . the root shell option would be double row other properties and PID can be assigned for the weld as well if needed.

* we create the property for seam weld by clicking shift + / in weld PID box and create the property.

*in this way we create the seam weld connection.

For spot weld :

* for spot weld we can creating 3D Point using COG tool and these 3D points are then converted into spot weld.

* after this we open connection manager and select newly created spot weld point and then select parts which we have to joint by spot weld , after this we select the FE rep typer as RBE3-HEXA-RBE3, After this D.O.F.s furthermore a PSOILD will need to be created and assigned.

RBE2 CONNECTIONS :

* For RBE2 connections we select nodes of parts and create the connections. we use create the two node and many node on RBE2 connection.

• CBUSH CONNECTION :

* This connection is used for window weather strip in which window glass is doen it is up and down motion smootly.

* for this connection we create curve from FE model and base we copy the curve and transform this curve to 10 mm out side so we create cbush connection on both side s ( mesh - perimeters - feat2curve ) (transform - copy )

* then we convert each curve line separately to spot line.

* after converting them we open connection manager and give the spacing value of bushes as 10mm then select parts and select the FE REP TYPE as RBE3 - CBUSH -RBE3, check the box of keep all branches after this create the pbush ID after this click on apply and realize the process will be repeated for each curve and create the pbush connection for all sodes.

* after this process is repeated to each and every spot line created we need to re orient them since they use a local coordinate system which is different from the globel coordinate system.

* we go to the database > elements > cbush . all the cbush elements are displayed search orient and then they are selected and then right click and modify.

* in the modify rules section we can add the orient rule and assign the with cord option for to it.

* and then click on + buttom and add 2nd rule in this we set CID RULE and create with value 0 and assign.

* in this way we connect the coordinates of all cbush same as globel coordinate system.

• Final model with all connections :

LEARING OUTCOMES :

* Undrestood various connection are available to connect the parts in FE model.

* learned different tools like feat2curve, assembly tool .

* understood the accurately the concept of spot and seam weld and cbudh connection.

Conclusion :

connection of given rear door of car model is successfully done with required conditions.