Week 9-Creation of 1D Connectors Challenge

For this challenge, you will have to mesh the given geometry. Provided below are the quality parameters that you have to follow.

Target Element size - 5 Units

S.N	Quality Criteria	Value
1	Aspect Ratio	5
2	Skewness	45
3	Warping	15
4	Taper	0.5
5	Min. Length	2 Units
6	Max. Length	8 Units
7	Min angle Quad	45
8	Max angle Quad	135
9	Min angle Tria	30
10	Max angle Tria	110
10	Tria %	15

Create connector and Attach the various parts of the given model

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

• Import the .hm model and the connector points in the model tree are hidden while meshing

• Each individual component is separated and meshed separately.

• If required, the components can be cleaned for topological errors and defeatured using manual or auto cleanup method.

• To clean geometrical errors: Geom - auto cleanup - set parameters - clean

2D surface Meshing & Mesh refinement

• To generate a shell mesh over each component:

• 2D - auto mesh - surfs (displayed) - target length =5 - specify Elem type and order - mesh

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

• Since volume tetras aren't being generated, the surfaces can be meshed with quads majority

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Assigning property card

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

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

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

• Then the necessary material values like poisons ratio, young's mod etc.. are specified

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

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

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

1D Connections

1.Seam-Quad(angled+capped+L)

For: 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

2.Left_Rail_2 & Front_truss_1:- Quad elements

• 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

3.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.

4.Hexa (Adhesive)

For: 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

5.Bolt Connector

For: 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)

6. For: Rear_truss_2 & Left_Rail_2

7.Spot-weld with Rigid Elements

For: 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)

8.Spot-weld with Spring Elements

For: 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

9.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 - create

CONCLUSION:

• Hence every components have been meshed and required connections have be defined and successfully realized. Finally the entire connections and meshed components are shown above.