Automotive Rear door connections using ANSA

AIM

*To implement the connections for the rear door model of automobile using ANSA.

INTRODUCTION

* Door model is one of the important assemblies which is having many number of connections in a single subsystem.

*Door model consists of hinges, latch,rails,window glass and suitable connections should be implemented on the particular areas for better NVH analysis.

*Spot welds, Seam welds ,Overlap and Yjoint shells are widely used in connections and the welds are determined depending the joining surfaces.

*C-Bush connection is done in this model and it is explained below with screenshots.

STEPS

*Importing the FE model and defining the properties.

*As observing the model, the hinge should be bolted and therefore creating a COG point and then converted it into bolt.

*On bolt coversion, created a rigid connection along the surfaces using RBE2 connection as shown below.

*The rigid connections in the hinge part is connected with two node RBE2 under NASTRAN deck.

*As the door is connected to body by a pivoted hinge and it should move along a particular fixed direction, the degrees of freedom should be considered in the properties of the two node connection made along the hinge as shown below.

Spot weld connection

*At some point on joining two different parts, rigid or bolt connection are not suitable and in such cases spot weld connections are followed for better result.

*On generating a spot weld, a COG point is created and then coverted into spotweld point.

*The spotweld point is selected and using connection manager, the two components to be joined are recognized as P1 and P2.

*Spot weld is created by determining the spot weld region with the help of RBE3-HEXA-RBE3 connection.

*Whwn it comes to handle, it is considered as mass element and it should be defined.

* The slots for door handle is defined as rigid and RBE2 many nodes connection is implemented.

*Subsequently two are again connected with the help of many node RBE2 connection.

*Define mass with the help of CONMi from elements under NASTRAN deck as shown below.

*Handle mass is of 100 grams and it is given in tonne.

Window glass connection

*The window glass is a significant part in door model, and when it comes to glass material welds,bolts or adhesives are not used as it is of brittle material.

*Weather strips in vehicles help in keeping wind and rain out of the car by sealing cracks and filling the gap between the door frame and glass. It makes sure the car windows and doors stay closed and secure. It is usually found along glass paths and doorframes.

*It plays a vital role in HVAC in the cabin.

*To determine the glass part, curves are created along the glass paths as shown below.

*Mesh<Perimeters<Feat2Curve

* The curve line of the glass is projected towards the outside part of the model at a distance of 10. Therefore the bush will be created filling the gap between the glass and the door model.

*The curve is generated along the quarter glass path inorder to provide bushand the curves generated are then converted into spotline.

*Using connection manager, the P1 and P2 surfaces are realized and the bush is created between the door frame and glass.

*RBE3-CBUSH-RBE3 is used to create the bush by giving search distance and introducing a new bush PID.

*In Bush ID INFO the stiffness(K) values are entered as per given values.

*The bush is created along the main and quarter glass paths.(as shown below)

*The orientation of the bush created is of vector form and it should be changed to coordinates to align with global cordinates.

*CBUSH properties is shown in database and it can be altered using modify to align with global coordinates as shown below.

RESULT

CONCLUSION

*Different sorts of connections such as spot weld, Bolt connection and CBUSH are introduced in the model.

*Door model consists of hinges, latch,rails,window glass and suitable connections should be implemented on the particular areas for better NVH analysis.

*The weather strip connection is implemented in the FE model using relevant options supported in ANSA.

*In absence of CAD data, the suitable connection to specific area should be figured out.