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WORKSHOP 8

MESH ON MESH 2D TO 3D

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MESH ON MESH2D TO 3D

Problem Description The lifting rig model has several

areas where elements are notconnected where they should beconnected.

Repair the model by moving/aligning several nodes and usingFinite Elements: Create/Mesh/On Mesh.

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General outline of analysis steps Import the MSC.Nastran model file lifting_rig.bdf Display element free edges

Region 3

Region 2

Region 1

Shown here is a plot of the element free edges. Notethree areas where there are unwanted free edges.They are labeled as Region 1, 2, and 3.

MESH ON MESH2D TO 3D

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Region 1

Region 2 Region 3

Again, note three areas where the elements are notconnected where they need to be. As before they arelabeled as Region 1, 2, and 3. Each of these regionsare to be repaired one at a time.

MESH ON MESH2D TO 3D

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General outline of analysis steps (continued) For Region 1 align the nodes of the 2D mesh to the nodes of the 3D mesh

Finite Elements: Modify/Node/Move. Align as many of the nodes between the two meshes as possible

Equivalence the model.

Before After

Note that thenodes here arenow aligned.

Region 1

MESH ON MESH2D TO 3D

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General outline of analysis steps(continued) Next use Finite Elements: Create/Mesh/On Mesh

to finish fixing the mesh. Finite Elements: Create/Mesh/On Mesh Click on the Delete Elements toggle Change Seed Option to Existing Boundary Click on Feature Selection

Select Boundary Hard Nodes, thenselect unmatched nodes as indicatedon the next page.

Under 2D Elem List select several rowsof elements as indicated on next page.

Specify the GEL as 0.2 Click on Apply

MESH ON MESH2D TO 3D

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Select unmatchednodes as BoundaryHard Nodes

Using polygon pickto select these 2Delements. Useenclose any portionof entity.

Region 1

MESH ON MESH2D TO 3D

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Region 1

General outline of analysis steps (continued) Region 1 repaired

MESH ON MESH2D TO 3D

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General outline of analysis steps (continued) Repair Regions 2 and 3 using the same technique

that was used for Region 1

MESH ON MESH2D TO 3D

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General outline of analysis steps (continued) Region 2 repaired

Region 2

MESH ON MESH2D TO 3D

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Region 3

General outline of analysis steps (continued) Region 3 repaired

MESH ON MESH2D TO 3D

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General outline of analysis steps (continued) Free edge plot

The free edge plot indicates that thecracks have now been eliminated.

MESH ON MESH2D TO 3D

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