HyperMesh and BatchMesher

HM-3670: Positioning a Dummy Using Limiting Constraints

HM-3670: Positioning a Dummy Using Limiting Constraints

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HM-3670: Positioning a Dummy Using Limiting Constraints

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Model Files

This exercise uses the dummy.hm file, which can be found in the hm.zip file. Copy the file(s) from this directory to your working directory.

 

Exercise: Using Limiting Constraints and Freehand Morphing to Position a Dummy and Morph the Seat

In this exercise, you will learn to position the H-point of the dummy on a seat cushion.

This helps to reduce design and remeshing of the seat based on the pre-stress analysis.  To do this exercise you will be using a limiting constraint and freehand morphing.

seat_dummy.zoom50

Figure 1 Model with Seat cushion and dummy

seat_nodummy.zoom40

Step 1:  Load and review the model.

Open the HyperMesh file dummy.hm

Step 2:  Create constraints.

1.From the menu bar select Morphing > Create > Morph Constraints.
2.Set name= const1.
3.Set type of constraint to on elements.
4.Set the option under nodes to bounded.
5.Set project along: to N1,N2 along negative z (choose from side of cushion).

hm3670_seat_n1n2

6.Set distance= 2.

This will ensure that there is a distance of 2 units between the dummy and the seat after the morphing is complete.

7.Use nodes >> by collector and select cushion.
8.Click select.
9.Use elems >> by collector and select dummy.
10.Click select.
11.Click create.

Constraints with a diamond shape are created.

hm3670_morphing_constraints

Figure 2 Morphing Constraints on Seat cushion and dummy

Step 3:  Morph the part.

1.Right-click MorphingConstraint in the Model Browser and select Hide.
2.From the menu bar, select Morphing > Free Hand and select the move nodes subpanel.
3.Switch moving method to translate.
4.For moving nodes, use nodes >> by collector and select cushion.
5.Click select.
6.For fixed nodes, use nodes >> by collector and select dummy.
7.Click select.
8.For affected elements, use elems >> by collector and select cushion.
9.Click select.
10.For the translate magnitude, set
•x = 0
•y = 0
•z = 80
11.Click morph.

The top surface of the cushion has conformed to the shape of the dummy.

The distance between the dummy and the seat-cushion is 2 mm.

hm3670_seat_morphed

Summary

Using limiting constraints, you are able to move a mesh such that it moves an adjoining mesh along with it, thus preventing penetration between the two of them.

 

 

See Also:

HyperMesh Tutorials