Week 9-Creation of 1D Connectors Challenge

Objective

• To mesh and apply the appropriate connectors to the frame assembly model. To know about the terms and debug the connectors if failed.

The specific connectors to be used to connect different parts

1. ‘Right_Rail_2’ & ‘Front_truss_1’: ‘Seam-Quad (angled+capped+L)’
2. ‘Left_Rail_2’ & ‘Front_truss_1’: ‘Quad elements’
3. ‘Front_truss_2’, ‘Front_truss_1’ & ‘Right_Rail_1’: ‘Spot weld’with 3 Layers and 5 mm Diameter
4. ‘Front_truss_2’, ‘Front_truss_1’ & ‘Left_Rail_1’: ‘Hexa (Adhesive)’
5. ‘Rear_truss_2’ & ‘Right_Rail_2’: ‘Bolt Connector’
6. ‘Rear_truss_2’ & ‘Left_Rail_2’: ‘Bolt Connector’
7. ‘Right_Rail_1’ & ‘Right_Rail_2’: ‘Spot-weld’with ‘Rigid Elements’
8. ‘Left_Rail_1’ & ‘Left_Rail_2’: ‘Spot-weld’with ‘Spring Elements'

Major points

Connectors are different types of 1D, 2D, or 3D elements (bars, rods, springs, links, welds, etc.) used to connect two or more components. The use of connectors plays a very essential role during the analysis of a certain component as it transfers load from one part to the other. There are different types of connectors available in HyperMesh like Spot weld, Bolts, Seam Welds, Adhesives, masses, etc

1. Applying connectors means giving information about the type of joining operations used to combine the different components of an assembly.
2. Connectors shown in red color are the connectors that are failed to create. To debug these types of connectors, check the details like tolerance, spacing, angle values, et al.
3. Connectors shown in yellow color are the connectors that are successful to create but failed to realize. To debug these types of connectors, check the direction, node, or element selection methods like Remesh, Quad transition, finding the near nodes, projection, imprint, or skip imprint, et al.
4. Connectors that are shown in green color are successfully created and realized.
5. The type of connectors being used in this model is spot weld, seam weld, and bolt joining.
6. The basic topology operations are done on the model and are meshed accordingly with the target size of 5mm.

1. Seam-Quad (angled+capped+L)

This connector is also called ‘Volvo Seam Quads’ as it is developed by Volvo, and is used in many industries. To apply this, the ‘seam’ option from the ‘1D>connectors’ tab was used. In the seam option, the ‘type’ was selected as ‘seam-quad (angled+capped+L)’, the location was set on ‘node-list’ and a line of nodes was selected at the joint of the two components. The spacing was set as 5.00 (equal to the element size), the components to be connected were selected in the ‘connect what’ menu, and tolerance was kept as 10. Weld angle was set as 45, cap angle 60, and runoff angle as 10. In the ‘property’ tab, the ‘frame assembly’ property was selected and the connector was created. The connector was not realized due to some error and hence was displayed in red color. Therefore, a ‘connectors’ tab was opened from ‘view>browser>HyperMesh>connector’. The created connector was selected and by right-clicking on it, the ‘realize’ button was hit. This realized the connector and was then turned green.

2D>Seam>location (Node list by path), Spacing (5), Components (RR2 and FT1)>Tolerance (10)>Type (Seam-Quad (angled+capped+L)), weld angle(60),cap angle (75), runoff angle (10) with remesh option>create

2. Quad elements

Quad connectors had to be created for these parts. To create the quads, ‘1D>connectors>seam’ was used. The type of connector was set as ‘quads’ with a spacing of 5mm, and tolerance of 10mm. the node list on the edge of the Front Truss 1 was selected where it was joining the other part. Both the components were selected in the ‘connect what’ tab. The property of ‘frame assembly’ was assigned and the connectors were created.

• 2D>Seam>location (Node list by path), Spacing (5), Components (LR2 and FT1)>Tolerance (10)>Type (Seam-Quads) with mesh option and use pitch size to imprint> create.

3. Spot weld with 3 Layers and 5 mm Diameter

Spot weld had to be used for these three above-mentioned components of the model. The diameter of the weld was specified as 5mm with a number of layers equal to 2. This spot weld was applied by using ‘1D>connectors>spot’ with the weld type as ‘plot’, property as ‘frame assembly’, and diameter as 5mm. the node path where the weld had to be applied was selected and the components were specified. As three components on top of each other had to be joined, the ‘num layers’ were set as ‘total 3’. This created a spot weld with the links passing through all three components. After ensuring the connector was realized, the spot weld was finalized as seen below

• 2D>Spot>Location (Node list by node path)> spacing (5), components>Num layers (Total 3)>Type (Plot)>diameter (5)> project and find nodes> create. After applying the connector the elements will be meshed again to obtain a good mesh if required

4. Hexa (Adhesive)

These components were joined using the ‘Hexa (adhesive)’ seam welding. Hexa (adhesive) connectors are used where the components are joined by using industrial adhesives. It creates a 3D (Hexa) element representing the adhesive joint. The number of layers and the number of coats of the connector can be changed according to the requirement. This connector creates a separate property and a separate component collector. To apply the Hexa (adhesive) the ‘seam’ option was selected from the ‘connectors’ tab of ‘1D’. The type of the seam welding was set on ‘Hexa (adhesive) from the list with a single layer and a single coat of adhesive. Similar to previous cases, the spacing was set as 5, tolerance as 10, and the node list and the components to be connected were selected.

• 2D>Seam> Seam>location (Node list by path), Spacing (5), Components>Tolerance (10)>Type (Hexa (adhesive))>create

5. Bolt Connector

 A ‘bolt (general)’ was created at two nodes by using the ‘bolt’ option from the ‘connectors’ tab of 1D. Here the type was selected as ‘bolt (general)’ which was set by default, and the property was selected. The ‘consider existing hole only’ option on the right side was changed to ‘create a hole if none’, and the components and the nodes where the bolts had to be created were selected. This created two holes around the two selected nodes. But along with this, the local mesh of those components was distorted. The mesh was thus optimized by mesh and using the optimization tools from the ‘2D>qualityindex’ option, and the connector was finalized.

• 2D>Bolt>Location (Nodes)> Components>Num layers (Total 2)>Tolerance (10)> Type (Bolt (general))>Create hole, if none>adjust hole position>create.

6. Bolt Connector

These components again had to be joined by bolt connectors. For this, a similar procedure as above was followed. But for this, the type of the bolt was changed to ‘bolt (CBAR)’ though it was specified in the challenge. Similarly, two nodes and both the components were selected, the ‘consider existing hole only’ option on the right side was changed to ‘create a hole if none’, and the connector was created as seen in the image below.

• 2D>Spot>Location (Node list by node path)> spacing (5), components>Num layers (Total 2)>Type (rigid)>diameter (5)> Find nearest nodes> create

7. Spot-weld with ‘Rigid Elements

SpotWeld with rigid elements had to be used as a connector to join these two components. This connector created RBE2 links to join the components. To create this spot weld, the ‘spot’ option was selected from the ‘connectors’ tab and the type of weld was set as ‘rigid’. The spacing was kept as 5mm, tolerance as 10, and diameter of the weld as 5, and the property was selected as ‘frame assembly’. The node list was selected on one side of the component and the connector was created. Similarly, by following this procedure, a spot weld was created on the other side of the component too. The image below shows both the connectors.

• 2D>Spot>Location (Node list by node path)> spacing (5), components>Num layers (Total 2)>Type (spring)>diameter (5)> Find nearest nodes> create.

8. Spot-weld with ‘Spring Elements

For both the Left rails, spot weld with spring elements had to be used. A similar procedure like the one above was followed. But instead of the ‘rigid’, the type was changed to ‘spring’. This created CELAS (elastic) elements as seen below.

• 2D>Spot>Location (Node list by node path)> spacing (5), components>Num layers (Total 2)>Type (Plot)>diameter (5)> Find nearest nodes> create.