Week 4- Challenge

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

PROCEDURE:

The component geometry is imported into HyperWorks.

A 3D mesh results in more number of nodes and elements which in turn increases the storage space and processing power required. Therefore to avoid this, a mid surface is created which represents the 3D model.

To extract the mid surface of the top bracket following commands are used,

Geom > midsurface > surfs > select surface > extract

The created mid surface is then renamed to ‘BRACKET_1’

Similarly, the same process is repeated for the bottom bracket (BRACKET_2)

Create a component to which this newly created second mid surface has to be moved and rename it to ‘BRACKET_2’,

Tab Area > Right Click > Create > Component

To move the mid surface to the component ‘BRACKET_2’,

Tool > Organize > collectors > surfs > dest_component = BRACKET_2 > move

After moving delete the middle surface.

Since only the mid surfaces are needed delete all the other solids and also the wireframe,

Tab Area > Right Click > Delete

Next 2D meshing has to be done. 2D meshing is done because for 1D elements nodes are needed and the 2D meshing provides these nodes. Before meshing washer split has to be provided,

Geom > quick edit > washer split > lines > offset value : 5 mm

To mesh with an element size of 5 mm,

2D > automesh > surfs > element size = 5 > mesh

For assigning steel as the material of the brackets,

Tab Area > Right Click > Create > Material > Rename=Steel

Both the brackets are assumed to be having a thickness of 2 mm. To assign these properties to the brackets,

Tab Area > Right Click > Create > Property > Rename to BRACKETS > T=2 > Card Image=PSHELL

Tab Area > Components > Left Click > Property > BRACKETS

Next, the specified 1D elements with the required DOFs have to be created at the required positions,

At A, To create a rigid/RBE2 link with only translational DOF,

1D > rigids > create > multiple nodes > calculate nodes > select nodes > check dof 1,2,3 > create

At B, To create a rbe3 link with all DOF,

1D > rbe3 > create > nodes = by path > select nodes > check dof 1,2,3,4,5,6 > create

At C, To create a rbe3 link with only x and y DOFs,

1D > rbe3 > create > nodes = by path > select nodes > check dof 1,2 > create

At D&E, To create a rbe2 link,

1D > rigids > create > multiple nodes > calculate nodes > select nodes > create

To create the cross sections of the rod, bar and beam elements, HyperBeam is used.

For Rod element,

1D > HyperBeam > standard section > standard section library: OPTISTRUCT > standard section type: Box > Create > Rename as ROD > specify the given dimensions

For Beam element,

Right Click Tab Area > Create > standard section > Hypermesh > standard I section > Rename as BEAM > specify the given dimensions

For Bar element,

Right Click Tab Area > Create > standard section > Optistruct > CROSS > Rename as BAR > specify the given dimensions

Return from HyperBeam by clicking on ‘Model View’.

Properties of the rod, bar and beam elements have to be specified such as the material and the cross section to be assigned,

Right Click Tab Area > Create > Property > rename as ROD > card image: PROD > material: steel > Beam Section: ROD

Right Click Tab Area > Create > Property > rename as BEAM > card image: PBEAM > material: steel > Beam Section: BEAM

Right Click Tab Area > Create > Property > rename as BAR > card image: PBAR > material: steel > Beam Section: BAR

Next, to create the required 1D elements,

To create a rod element at A,

1D > rods > create > elem types=CROD > property=ROD > Select nodes

To create a beam element at B,

1D > bars > create > elem types=CBEAM > property=BEAM > Select nodes

To create a bar element at C,

1D > bars > create > elem types=CBAR > property=BAR > Select nodes

To apply a mass of magnitude 10 at RBE2 links at D & E,

1D > masses > create > elem types=CMASS1 > property=BRACKETS > mass=10 > Select node > create

Next, to join the two components with Spring elements,

1D > springs > create > elem types=CELAS1 > property=BRACKETS > Select corner nodes

Change to ‘1D Detailed Element Representation’ and ‘2D Detailed Element Representation’

FINAL MODEL IMAGE:

CONCLUSION:

The required 1D elements with the specified cross section were created on the given component.