Week 4-1D Element Creation Challenge

Week 4-1D Element Creation Challenge

1. Aim

Mesh the Given component with the Size of 5 Units. Create 1D elements on the following component with the given cross-section and DOF

a. Rod element:- Translational DOF should be Constrained with the RBE2 link

Cross-Section: BOX- Dimension a= 12 mm

dimension b=10 mm

Thickness t= 0.75 mm

b. Beam element:- All DOF should be constrained with the 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:- Constrain only x and y DOFs With RBE3 link

Cross-section: X 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 the RBE2 link

f. Join the two components with Spring elements

Fig 1: Reference of The Model

2. Objective

• Import the given IGES geometry to Hyper Mesh
• Extract the mid-surface of the brackets.
• Create Components, Materials, Parts and Properties according to the model.
• Create 1D elements with mentioned cross-sections and dimensions
• Apply the mass of the given value to the specified areas.
• Join the brackets with spring elements.

Fig 1: Isometric View of The Model

3. Procedure

Step 1: Importing and Mid-Surface Extraction

First We have to import the file to hyper mesh. Here, the file is in IGES format.

• File >> Import >> Geometry >> Browse the file location >> Select The File >> Import.

After a quick auto cleanup, and washer splits creation, the geometry is ready for extraction of mid-surface. The mid-surface of the model is created by,

• Geometry >> Mid surface >> Auto mid surface >> Target Element Size = 5 Units >> Select The Surface >> Extract.

Fig 2: Mid Surface of The Model

Here, the mid surface of brackets is saved in a component separately.

Step 2: Creating Components, Properties, and Materials.

For 1D element creations, initially, we have to create and assign components. For creating components,

• Model View >> Element & Geometry >> Right Click >> Create >> Componets >> Rename >> Ok.

Similarly, the material and the properties can be created. For Material

• Model View >> Element & Geometry >> Right Click >> Create >> Material >> Rename >> Ok

While Creating the material, the Card Image is to be changed. In this case, there is no specified card image, so Card Image is taken as 'MAT 1'. For properties,

• Model View >> Element & Geometry >> Right Click >> Create >> Properties >> Rename >> Ok

Also, these properties have separate Card images as well. Assign materials to these properties

Properties	Card Image	Material
Bracket	PSHELL	Steel (MAT 1)
MS	PSHELL	Steel (MAT 1)
Rod	PROD	Steel (MAT 1)
Beam	PBEAM	Steel (MAT 1)
Bar	PBAR	Steel (MAT 1)
Spring	PELAS
Mass	PMASS

Fig 3: Components, Material and Properties.

Step 3: Creating 1D Elements

The 1D elements are constructed by using a Hyperbeam. The 1D elements (Bars, Rods, Beams, etc) have specific cross-sections. For this,

• 1D >> Hyperbeam >> Standard Selection >> Standard Selection Library (HYPER BEAM) >> Standard Section Type (Type Of Cross Section) >> Give Dimensions >> Ok.

Here, we need to create 3 types of cross-sections.

For 'Box Section', Standard Section Type = Thinwalled Box

For 'I Section', Standard Section Type = Standard I Section

For 'Cross Section', Standard Section Type = Cross

We can also construct these elements in hyper beam interface by

• Hyper beam Interface >> Right Click on Entities >> Create >> Standard Section >> Opistruct >> Select Section Type >> Give Dimensions.

Fig 4: X Section

Fig 5: Box Section

Fig 6: I Section

Assign these beam sections to the following properties

Property	Beam Section
Rod	Box Section
Beam	I Section
Bar	X Section

Step 3: Creating RBE2 and RBE3 Links and Assign the DOF Constraints

For creating RBE2 links,

• 1D >> Rigids >> Select Nodes (By Path) >> Select DOF Which to be constrained >> Create

For Creating RBE3 links

• 1D >> RBE3 >> Select Nodes (By Path) >> Select element type = RBE3 >> Select DOF Which to be constrained >> Create

("dof1, dof2, dof3 = Translation in x, y and z axis" and "dof4, dof5, dof6 = Rotation in x, y and z axis")

Each set of links has different DOF constraints. So try to save links in different components.

Fig 7: RBE2 and RBE3 Links

Step 4: Construction Of Rod Element

According to the objective the Rod element is created by connecting RBE2 elements having translational DOF constraints.

• 1D >> Rods >> Create >> Select Master Nodes Of Both RBE2 Links >> Element Type = CROD >> Property = Rod (Card Image = PROD)

Fig 8: Rod Element

Step 5: Construction Of Bar and Beam Elements

The Beam element is created by connecting RBE3 elements having all DOF constraints.

• 1D >> Bars >> Create >> Select Master Nodes Of Both RBE3 Links >> Select Orientaion Nodes N1, N2, N3 >> Element Type = CBEAM >> Property = Beam (Card Image = PBEAM)

The Bar element is created by connecting RBE3 elements having DOF constraints in the x and y-axis.

• 1D >> Bars >> Create >> Select Master Nodes Of Both RBE3 Links >> Select Orientaion Nodes N1, N2, N3 >> Element Type = CBAR >> Property = Bar (Card Image = PBAR)

Fig 9: Beam and Bar Elements

The 1D representation can be visible by turning on the "1D Traditional and Detailed Element representation"

Step 6: Assigning Of Mass

The mass is applied on two RBE2 links on the edges of bracket 01.

• 1D >> Masses >> Select Master Nodes Of Both RBE2 Links >> Mass = 10 Units >> Property = Mass (Card Image = PMASS) >> Element Type = CMASS1 >> Create

Fig 10: Mass Representation

Step 7: Creating Spring Elements

The two brackets are connected by spring elements by creating springs on 4 end nodes.

• 1D >> Springs >> Select Start Nodes and End Nodes >> Select dof Constarints (dof2) >> Property = Spring (Card Image = PELAS) >> Element Type = CELAS1 >> Create.

Fig 11: Springs

The 2D representation can be shown by turning on the "2D Traditional and Detailed Element representation"

Fig 12: Final Result

4. Conclusion

• The File is imported and extracted mid-surface with mentioned target element length.
• The components, materials and properties are created and assigned the corresponding criteria and values.
• RBE2 and RBE3 links are created with mentioned constraints.
• 1D elements are created by joining corresponding rigid links.
• Create and assign masses on the following RBE2 links
• The brackets are connected using springs with the given criteria

5. Result

• For the model, 1D elements with the given cross-section and DOF is constructed.