Challenge

Creating Rod, Bar & Beam Element in Hypermesh

KKumarasamy N8 Dec 2020

AIM :

To Create 1D elements on the following component with given cross-section and DOF.

OBJECTIVE :

a. Rod element:- with only translational DOF and RBE2 link

Cross-Section: BOX- Dimension a= 12 mm

dimension b=10 mm

Thickness t= 0.75 mm

b. Beam element:- with all DOF and RBE3 link

Cross-Section: I Section- Dimension a= 8 mm

Dimension b= 10 mm

Dimension c= 8.5 mm

Thickness t1= 0.75 mm

Thickness t2= .6 mm

Thickness t3= .6 mm

c. Bar element:- with only x and y DOFs With RBE3 link

Cross-section: CROSS section- Dimension DIM1= 5 mm

Thickness DIM2= 1.2 mm

Dimension DIM3= 10 mm

Thickness DIM4= 1.2mm

d. & e. apply the mass of magnitude 10 with RBE2 link

f. Join the two components with Spring elements

THEORY :

RBE2 Panel :

A rigid element is an element created in a space between two nodes of a model where a rigid connection is desired. In the RBE2 link, Load will be distributed equally for all nodes.

Rigid link elements can be created with dependent nodes attached to an element as a SET. If a rigid link with a dependent node-set is deleted, the associated node-set is also deleted. If the dependent node-set in any panel is deleted, the connected rigid link element is also deleted. Dependent node sets are automatically created when rigid link elements are created. A node-set created in the Sets panel can be connected as a set of dependent nodes to a rigid link element independent node.

RBE3 Panel :

RBE3's are interpolation constraint elements, where the motion of a dependent node is defined as the weighted average of the motions of a group of independent nodes. The dependent degrees of freedom and weighting factors can be specified or automatically calculated based on the geometry

RBE3's are typically used to distribute loads applied to the dependent node amongst the selected independent nodes. In the RBE3 link, Load distribution will be varied.

Masses Panel :

Use the Masses panel to create mass elements. A mass element rests on a node and is used to represent mass.

Rods Panel :

Use the Rods panel to create rod elements. A rod element is an element created in a space between two nodes of a model where rod properties are desired. The two nodes are related to each other based on the properties of the rod element connecting them

Hyperbeam Panel :

Use the HyperBeam panel to create beam cross-section entities that you can use to simplify complex portions of your model into simple bar elements. The HyperBeam panel is arranged into several subpanels. Each subpanel covers a different type of beam section, except for the more general edit section and section utils (utilities) subpanels. It can move freely between subpanels. Working on one subpanel will not be lost if switch to a different subpanel.

Springs Panel :

Use the Springs panel to create spring elements. A spring element is an element created in a space between two nodes of a model where a spring connection is desired.

PROCEDURE :

1. Import the given Component using the Import option in Hypermesh.

Fig: Imported Parallel Bracket Model

2. Creating a Mid-surface of the given component by using Geom-->midsurface option.

3. Use the extraction options subpanel to define an offset option to mid surface in extraction settings.

4. Use the Auto Midsurface subpanel to extract the mid surface of a more complicated group of surfaces that represent a solid part in one step.

5. After creating a Mid surface of the given component, Use Washer Split option and create a washer as 5mm on each pinhole.

Fig: Midsurface Component

6. After Creating a Mid surface, Go to 2D-->automesh option and set element size and mesh the component.

7. While meshing, Keep the number of elements on both sides of the part as equal to avoid tria & quad elements.

Fig: Mesh Component

8. Create Steel Material Card & Property Card for the Parallel Bracket 1 & 2 by using Model Browser-->Rightclick-->Create-->Material & Property option.

9. Assign the Material & Property for Bracket 1 & 2 in the Component.

Fig: Created Material & Property

a. Rod Element :

10. Creating a Rigid body RBE2 link with only translational DOF in a.

11. Go to 1D-->rigids option and set as multiple node & calculated node and Select the only translational DOF and select the edges and Click Create.

Fig: RBE2 with only translational DOF

12. Go to 1D-->Hyperbeam-->Standard Section and select type as thin-walled box and Click Create.

Fig: Box Section

13. After Creating Box Section, Go to Model Browser and Create Property for Rod and Select Beam Section as Box Section.

14. Create a new Component as Rod and assign the Rod Property to the rod component.

15. Go to 1D-->rods option and Set Property as Rod and element type as CROD and Select Master node of two rigid body and Create it.

Fig: Rod Element

b. Beam Element :

16. Creating a Rigid body RBE3 link with all DOF in b.

17. Go to 1D-->rigids option and set as multiple node & calculated node and Select all DOF and select the edges and Click Create.

Fig: RBE3 with all DOF

18. After Creating the RBE3 link, Go to Hyperbeam view-->Create-->Standard Section-->Hypermesh and select type as Standard I Section and Click Create.

Fig: I Section

19. After Creating I Section, Go to Model Browser and Create Property for Beam and Select Beam Section as I Section.

20. Create a new Component as Beam and assign the Beam Property to the Beam component.

21. Go to 1D-->bars option and Set Property as beam and element type as CBEAM and Select Master node of two rigid body and Create it.

Fig: Beam Element

b. Bar Element :

22. Creating a Rigid body RBE3 link with only x and y DOF in c.

23. Go to 1D-->rigids option and set as multiple node & calculated node and Select only x & Y DOF and select the edges and Click Create.

Fig: RBE3 with only x & Y DOF

24. After Creating the RBE3 link, Go to Hyperbeam view-->Create-->Standard Section-->Optistruct and select type as Cross Section and Click Create.

Fig: Cross Section

25. After Creating Cross Section, Go to Model Browser and Create Property for Bar and Select Beam Section as Cross Section.

26. Create a new Component as Bar and assign the Bar Property to the Bar component.

27. Go to 1D-->bars option and Set Property as bar and element type as CBar and Select Master node of two rigid body and Create it.

Fig: Bar Element

d & e - Add Mass :

28. Go to 1D-->rigids option and set as multiple node & calculated node and Select all DOF and select the edges on two sides and Click Create.

Fig: RBE2 link with all DOF

29. After Creating the RBE2 link, Go to Model Browser and Create Property for Mass, and Select Material as Steel.

30. Create a new Component as Mass and assign the Mass Property to the Mass component.

31. Go to 1D-->Masses option and select RBE2 Master node and Set mass value as 10 and Property as Mass and Select elem type as CMASS1 and Click Create.