Week 9-Creation of 1D Connectors Challenge

AIM: To mesh the given geometry and create 1D connectors at desired locations using Hypermesh in optistruct.

OBJECTIVE:

The following connections have to be realized in each respective component:

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 2 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

9. Rest all the component left Join them with suitable connectors.

EXPLANATION:

1. Import the given .hm model.

2. Each individual component is separated and meshed seperately.

3 .If required, the components can be cleaned for topological errors and defeatured using manual or autocleanup method.

4. To clean geometrical errors: Geom - autocleanup - set parameters - clean.

5. To generate a shell mesh over each component: 2D - automesh - surfs (displayed) - target length =5 - specify elem type and order - mesh.

6. However to achieve a perfect mesh without quality errors the comp is sectioned into different surfaces using surf trim option and meshed separately.

7. Since volume tetras arent being generated, the surfaces can be meshed with quads majority.

8. A single property and material card is added for every component.

9. Assuming every comp has the identical thickness and material, a single card is added to each

10. To create a material card: name =steel - type=ISOTROPIC - card=MAT1

11. Then the necessary material values like poissons ratio, youngs mod etc.. are specified

12. Similarly a new property card is created with the PSHELL card image and the above mat card is assigned to it.

13. The thickness of the comp are also specified in the property card.

14. Each card is assigned the property card which is linked to the material card.

i. Seam-Quad(angled+capped+L):

Right_Rail_2 & Front_truss_1:

• To create a seam weld: Connectors - seam.
• Select the nodes (by path) on one of the component.
• Tolerance = Specify the search distance (10mm).
• Select the two components and keep the imprint check on.
• Weld type is set as seam-quad (angled+capped+L).
• The weld angle can be altered but an angle of 60 or 45 is widely preferred based on the alignment of the two components.
• The spacing is set a 5mm. Spacing defines the distance between the two adjacent weld elements.

ii. Seam-Quad elements:

Left_Rail_2 & Front_truss_1:

• To create a seam weld: Connectors - seam.
• Select the nodes (by path) on one of the components.
• Tolerance = Specify the search distance (10mm).
• Select the two components and keep the imprint check on.
• Weld type is set as quad and the spacing (distance between the two adjacent weld elements) is kept as 5mm.

iii. Spot weld with 3 Layers and 5 mm Diameter:

Front_truss_2, Front_truss_1 & Right_Rail_1:

• To create a spot weld: 2D - connectors - spot - type=weld
• Select all the required nodes where the location of the spot weld has to be placed.
• Then select all the 3 components
• Specify a diameter of 5mm and number of layers as 3.(NOTE: Since the layer is set as 3, a minimum of three components have to be selected and in case only two components are present then the layer has to be set as 2).

iv. Hexa (Adhesive):

Front_truss_2, Front_truss_1 & Left_Rail_1:

• To create a seam weld: Connectors - seam.
• Select the nodes (by path) on one of the component.
• Tolerance = Specify the search distance (10mm).
• Select the two components and keep the imprint check on.
• Weld type is set as hexa (adhesive) under the weld type category.
• The strips and coats of the weld can be altered. In this case, the strip is set as 2 and a single coating is specified.

v. Bolt Connector:

Rear_truss_2 & Right_Rail_2:

• To create a bolt connector: Connectors - bolt.
• Specify the location of the bolt by selecting two single nodes at a certain distance in one of the component since two bolt connectors are being realised.
• Select the two components which has to be fixed by the bolt.
• Select the option to create a hole to define the bolt as a physical element (Note that this will modify and alter the neighbouring mesh).
• Specify the search length (about 10mm).

vi. Rear_truss_2 & Left_Rail_2:

vii. Spot-weld with Rigid Elements:

Right_Rail_1 & Right_Rail_2:

• As similar to previous spot weld creation, this spot weld is created using rigids instead of weld.
• To create a spot weld: 2D - connectors - spot - type=rigids.
• Select all the required nodes where the location of the spot weld has to be placed. (by path).
• Then select all the 2 components.
• Specify the diameter and number of layers as 2 (since only two components are present).

viii. Spot-weld with Spring Elements:

Left_Rail_1 & Left_Rail_2:

Similarly as done for the previous case, here the spot element type is set as spring instead of rigid or weld.

ix. For other components

• In case of the shell component with the hole, a adhesive connection is made.
• Adhesives are RBE3 elements that distribute load applied to its master node. Unlike RBE2 elements, RBE3's do not impart infinite stiffness to the component.
• To create adhesives using area connector method:
• 2D - connectors - area - type=adhesive - select elems and components - (optional) specify coat layer - specify search tolerance - createFor other components.
• Similarly, a seam weld is created on other components.
• A seam weld with a (vertical+angled) type is created.
• 2D - connectors - seam - type=seam-quad(vertical+angled)
• Then specify the weld angle as 45 degree and slected required elems and components.

CONCLUSION:

1. Learned how to create meshing dor the component.
2. Learned how to create different connections using seam, spot options using 1d and 2d commands.
3. Learned how to create spacing between the elements.
4. learned how to use use imprint option.