Challenge

Week 9-Challenge

AAtish Tiwari28 Oct 2020

AIM :

Deploying the connection using Hyperworks

Objective :

Create the connectors and attach the different parts of the model

Right_Rail_2 & Front_truss_1:- Seam-Quad(angled+capped+L)
Left_Rail_2 & Front_truss_1:- Quad elements
Front_truss_2, Front_truss_1 & Right_Rail_1:- Spot weld with 3 Layers and 5 mm Diameter
Front_truss_2, Front_truss_1 & Left_Rail_1:- Hexa (Adhesive)
Rear_truss_2 & Right_Rail_2:- Bolt Connector

Rear_truss_2 & Left_Rail_2:- Bolt Connector

Right_Rail_1 & Right_Rail_2:- Spot-weld with Rigid Elements

Left_Rail_1 & Left_Rail_2:- Spot-weld with Spring Elements

Rest all the component left Join them with suitable connectors

Introduction :

Connectors as the term said is used to connect the two or three components. They are geometric entities that are used to represent the CAD geometric connection in terms of FEA.

Now there are a number of connectors availabl;le in hyperworks but primarily connectors like spot, seam, bolt and adhesive or area are used.

Procedure :

Step1 : importing the model into hyperworks and performing the clean up

The current model is a frame assembly welding model that needs to be deployed with the required connection.

Fig- frame assemebly welding model

Clean up :

Before proceeding with the meshing of the assembly it needs to be reviewed and cleaned up.

Fig- red lines indicating discontinuity

As seen from the above figure, the two lines need to be pasted to form the green line or the complete geometry. That can be done by using the toggle option under the quick edit tools .

]

Fig - discontinuity fixed (green lines)

Step 2: Performing the 2D meshing

There are no quality criteria given so we will be taking the arbitrary values. Here we take the element size as 5 and perform the 2D meshing on the components given.

Fig- freme assembly meshed with elemnent size 5

Step 3 : Deploying the connectors

After the meshing is performed the connectors will be deployed at specified locations using the 2d connectors such as seam , spot and area.

1. Seam weld (angle-capped-l) connector

This connection needs to be deployed between the component right rail2 and front truss 1. The steps to followed as

Switch on the right rail 2 and front truss 1 FEA only from the tab bar.
Then go to the 2D > connectors > seam > select the seam quad (angle+CAPPED+L)

Select the nodes and then select the components as the two components
Spacing values will be elements size which is 5 and switch on the retain nodes
Tolerance is the search distance between two components. Here its 5
Then create the connection. If the connection is realized it will turn into green color other it will be red color or unrealized will turn yellow color.

Fig- seam angle+capped+L connection

Note :

There are certain terminology related with the weld that are

Weld angle-the distance between the normal projection and the quad direction.

Principally it is allowed to define weld angles between 0.0 and 90.0. If the value is set to 0.0 an internal thickness-based calculation is used. If the value is set to 0.0 and no thickness is defined the connector will fail.

If the angle is created in the wrong direction, the seam can be reverted by enabling the reverse direction checkbox and performing a derealization.

Cap angle-Depending on the seam-quad type, the cap angle is measured differently.

Measured between the normals of the cap element and the second-to-last element of the seam.

Measured between the edge normals of the cap element and the second-to-last element of the seam in the plane of the opposite link.

Height-the distance between the projection point and the start-point of the angled quads.

Only available for T-seams.

The height needs to be chosen in an extent to bridge the gap between the links. Also, the height strongly influences the quad length, especially in cases of very large weld.

2. Quad elements :

This connection will be deployed between the left rail 2 and front russ 1. Quad connectors fall under the seam connectors only. The steps are same as the above only

Select the nodes from one component
Select the components as two left rail2 and front truss 1
Tolerance and spacing will be same as earlier and then create

The quad imprint is kept only because we have the existing elements that need to connect otherwise if the imprint is turned off duplicate elements are created . ]fig - seam qaud connection

3.Spot weld

Here the spot weld is used to connect three components as front truss 1,2 and right rail 1. Steps to deploy spot connection are as followed

Switch on only 3 required components from the tab bar
Go to 2D>connectors >spot
Select the type as weld
Select the nodes from the any top component and the components as all three components

The number of layers are put three because the components here 3 only
Diameter as 5 and the rest of the option as mesh dependent and project and find nodes are kept as it is only.

Fig- spot weld

4. Hexa adhesive

This connection falls under the seam connectors only. Here its deployed between three components as front truss 1,2 and the left rail1. Steps to deployed as follows

The components that are required are only switched on
Go to 2D>connectors >seam > type as hexa adhesive
Select the node list from one component and then select the comp as two components
Spacing and tolerance are kept as 5 .
Coats and strips are kepts as1 as there is significantly small spacing between two components the elements will fail in that connector.
We can chose the midpoint or positive or negative direction to obtain the connection

Fig- seam hexa adhesive

Note :

The hexa connection is developed as a rbe3 connection. The difference between the RBE2 and RBE3 is that RBE2 is considered to be infinitely rigid while RBE3 are considered to be a a little stiffer.

5. Bolt connector

The bolt connection is also a RBE2 based connection since they are considered to be rigid and they are not used as a component for study. Here we have to deploy the 2 bolt connection

Rear truss 2 and right rail2

Rear truss 2 and left rail 2

The steps are as follows

Switch on the required component for the bolt connection
Go to 2D>connectors > bolt

Select any one node under the node
Select component as two components
Layer as 2 since only two components are present
Tolerance as 5
Type of the bolt as general
Now select the create hole , if none since here there are holes present and create