Exer04 Handle-patran

8/12/2019 Exer04 Handle-patran

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Handle 4-1

BASIC

ANALYSIS

XY

Z

1

4

Handle


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Handle4-2


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Handle

BASIC

ANALYSIS

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Model Description:

The above handle represents a good model for solid elements. The curved shape and rounded pro-

file together with the variable loading conditions would not be possible to achieve with other types

of elements. Because we are limited to 300 nodes in the demo version we will only model half of

the handle and with a lower mesh density than we would like for normal analysis.


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Handle4-4

Exercise Procedure:

1. Start up MSC/NASTRAN for Windows 3.0 and begin to create a new model.

Start MSC/N4W by double-clicking on the MSC/N4W icon. When the Open Model Filedialog box

appears; choose New Model.

2. Importing the Geometry.

Once again the geometry for this example has been created for you. It is a simple series of curves

that were created in MSC/N4W and written out as a neutral file. To import the base geometric data.

The File/Import/Geometrymenu should be selected to import the geometry.

Navigate to the mscn4w30\examplesdirectory and select mhandle.NEU.

The FEMAP Neutral Read Options Dialog Box is displayed, providing several options for how to

treat the incoming data. Accept the defaults.

Open Model File: New Model

File/Import/FEMAP Neutral...

File Name: mhandle.NEU

Open


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Handle

BASIC

ANALYSIS

4-5

To modify the view to view the three dimensional nature of the imported geometry, use the

Dynamic Rotate button on the MSC/N4W toolbar.

3. Rotate the View.

Press the Dynamic Display button on the toolbar.

MSC/N4W displays the Dynamic Display dialog box at the bottom of the screen.

To dynamically rotate your model, move the cursor inside the graphics window, and then press and

drag it left to right and up and down. This will dynamically rotate the model. By pressing and hold-

ing the Shiftkey, and pressing and dragging the mouse up and down, you can scale the view

OK

X

Y

Z

X

-0.4 -0.2 0. 0.2 0.4 0.6 0.8 1. 1.2 1.4 1.6 1.8 2. 2.2 2.4 2.6 2.8 3.

Y


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Handle4-6

dynamically. Using the Ctrlkey in combination with pressing the left mouse button and dragging,

you can dynamically pan the view. When you get the model in an orientation similar to the oneshown.

We will now create the surfaces that represent the outside of this part.

4. Create Surfaces.

The surfaces that represent the outside of this handle will be created with the Create | Surface |

Aligned Curves function. Create | Surface | Aligned Curves takes curves aligned in the same para-

metric direction and construct a lofted surface between them.

OK

Geometry/Surface/Aligned Curves...

Select All

OK

Cancel

X

YZ

X

-0.4 -0.2 0. 0 .2 0.4 0.6 0.8 1. 1.2 1.4 1.6 1.8 2. 2.2 2.4 2.6 2.8 3.

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0.

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V1


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BASIC

ANALYSIS

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The surfaces are now defined, it is also necessary to mesh the end of the part so that a complete

enclosing triangular surface mesh can later be generated. We will do this with two MSC/N4W

Boundaries for each of the closed curve ends.

Select the 2 arcs at the right end.

Select the 2 arcs at the bottom left end.

The geometry portion of this example is now complete.

Geometry/ Boundary Surface...

OK

Geometry/ Boundary Surface...

OK

X

YZ

X

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Y

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-0.2

0.

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0.4


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5. Materials, Properties and Meshing.

We can now mesh the surfaces and boundaries just created.

This part will be solid meshed with the tetrahedral automatic mesher that comes as part of the

MSC/N4W The first step in a solid mesh is to create a triangular surface mesh that completely

encloses the solid. This triangular surface mesh is used as the starting point for the volume mesher

which fills the interior of the triangular surface mesh with elements. In this example the solid mesh

command automatically creates the surface mesh needed for the solid mesh and deletes it when the

solid mesh is complete.

MSC/N4W now displays the Automatic Mesh Sizing Dialog Box. A.) Change the Element Size to

0.4.

Mesh/Geometry/Solid from Surface...

Select All

OK

Element Size: 0.4

X

YZ

X

-0.4 -0 .2 0 . 0.2 0.4 0.6 0.8 1. 1.2 1.4 1.6 1.8 2. 2.2 2.4 2.6 2.8 3.

Y

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-0.2

0.

0.2

0.4

V1


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ANALYSIS

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Since no materials has been created MSC/N4W prompts you define one. you can enter in values or

press the Load button to bring up the material library.

The material library shipped with MSC/N4W contains material properties using English and Metric

units. You can create your own materials and store them in this library or create your own library.

OK

Load


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The automesh solids dialog box appears. Leave the values as the defaults.

Library Entry: 7075-T651 Al Plate .25-.5

OK

OK

Note:

Remember, there are no units in MSC/N4W. All dimensions must be kept con-

sistent with the unit system you use to define your material properties. Always

make sure this is correct from the beginning because there is no way to fix

inconsistencies in units once the model is built.

OK


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ANALYSIS

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MSC/N4W asks you if it is OK to mesh boundary surfaces. In this case they are part of the solid so

press Yes.

Press Ctrl-Qto bring up the MSC/N4W Quick View Options Dialog Box.

The model is shown in wire-frame mode. As your models become more complicated, it is often

necessary to view them with their hidden lines removed. To do so:

Alter the model display with toQuick Hidden Line.

Yes

Geometry Off

Labels Off

Done

View/Select... (F5)

Model Style: lQuick Hidden Line

XY

Z


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MSC/N4W now displays your model sorted back to front, effectively hiding elements that are

behind other elements.

Rotate the model to the ZX Frontview for the next step of the exercise. You can also return the

view back to the Wireframe(optional).

OK

View/Rotate...

ZX Front

OK

View/Select... (optional)

Model Style: lDraw Model

OK

X

Z


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6. Constraint the Model.

Since this model uses tetrahedral elements, the individual nodes only use translational degrees of

freedom. We will first fix the base by constraining all three translational degrees of freedom, and

then constrain the right side with an X-Symmetry boundary condition.

Select Nodes on the bottom left boundary surfaceby dragging a box around them using the box-

pick (Shift+Left mouse button).

Select Nodes on the upper right boundary surface.

Model/Constraint/Nodal...

Title: Constraint

OK

OK

Pinned

OK

OK

X Symmetry (or just constrain the TXdegree offreedom)

OK

Cancel

XY

Z


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7. Loading the Model.

A load will be applied to the center of this handle in the plane of symmetry. Since we are applying

a load in the plane of symmetry, we are effectively applying twice the load that is input.

Select the upper right boundary surface (the plane of symmetry, surface 3).

The load will be expanded to the nodes during translation.

This model is now ready for analysis

Model/Load/On Surface...

Title: Load

OK

OK

(highlight) Force

FZ 5000

OK

Cancel

Z

Exer04 Handle-patran

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