Week 9-Creation of 1D Connectors Challenge

Creation of 1D Connectors

AIM :-

Mesh the provided model for given parameters and then connect each component by the relevant connector asked.

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

PROCEDURE :-

Setting up model

• At the very first import the .hm model and the connector points in the model, tree are hidden while meshing

• Components are separated and meshed seperately.
• The components can be cleaned for topological errors and defeatured using specified method, if required
• In order to clean geometrical errors: Geom - autocleanup - set parameters - clean

2D surface Meshing & Mesh refinement

• Generating a shell mesh over each component:
• 2D - automesh - surfs (displayed) - target length =5 - specify elem type and order - mesh
• The surfaces can be meshed with quads majority as volume tetras aren't being generated

• Correspondingly , symmetrical components can also be trimmed about the mid point and also can be meshed and reflected about the central axis

• Finally the components are meshed using 2D elems (trias and quads)

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 poissons ratio, youngs 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. Seam- Quad elements

For: 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

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)

The realised bolt connection is shown below

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

• Similarly, a seam weld is created on other components.
• A seam weld with a (vertical+angled) type is created as shown below:
• 2D - connectors - seam - type=seam-quad(vertical+angled)
• Then specify the weld angle as 45 degree and slected required elems and components.
• The realized connection is shown below

CONCLUSION :-

• Therefore every component is meshed and required connections are defined and sucessfully realized.
• The entire connections and meshed components are shown below in following figure