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Z88 A URORA ® E XAMPLE M ANUAL

Example 6: Crane truss

(truss No. 4)

is a registered trademark (No. 30 2009 064 238) of Univ. Prof. Dr.-Ing. Frank Rieg

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Example Manual

6. Example: Crane truss (truss No. 4)

This example is very easy a straight forward: 20 Nodes and 54 trusses constitute a 3D

framework. The manual creation of these structures is actual almost the simplest way,

CAD-programs are often not very helpful. But let us take a look to the ready model first.

Input file:

b2_x.dxf 

structure information’s from CAD-program

The exercise:

A crane truss consists of 54 trusses (No. 4), 20 nodes and is a 3D-framework. The nodes

1, 2 and 19, 20 are mounted, the nodes 7 and 8 are exposed to a force of 30,000 N. The

total length is 12 m . The values in the example file are in mm but it is also admissible to

use m , if the other units like E-modulus and cross section area are adequate to m too.

The E-modulus is 200,000 N/mm², Poisson ratio ν is 0.3. The cross section area of every

FE-truss is 500 mm². This example is token from Schwarz, H.R.: Methoden der finiten

Elemente (1991) .

At first a new project is created by using

and

- in this case for example

Example6 - the dialogue is to be confirmed with Enter and completed with OK .

With the button

the appending file b2_x.dxf can be imported. A context

menu on the right side appears, it can be used to load the DXF-file

( Figure 1 ) . Because the FE-structure is created out of a CAD-system, you have to choose

the item conversion of DXF FE Mesh to z88i1.txt as import option.

By clicking the button

you switch to the preprocessor. To apply constraints define a

new load case has to be added with

on the right side. Naming it and con-

firming creates the load case.

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Example Manual

Figure 1: Import the DXF-structure

By clicking

, the constraint menu is opening and at the same time the

picking view. With

you can switch to the mesh view, where it is possible to label

nodes. Use View  Labels  Nodes for this purpose,

switches back to the picking

view. With the help of the CTRL-Key you can choose the nodes 1, 2, 19 and 20, and force

its displacements to 0 in every direction. Now deselect them with Unselect and pick the

nodes 7 and 8 instead. They should be loaded by a force of -30,000 in z-direction.

( Figure 2 )

saves all these constraints.

Figure 2: Constraints for example 6

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Example Manual

With

you switch to the file card “Apply material” . There already exists a ma-

terial on the right side (E=200,000 ν=0.3). The button

quits the dialogue.

To calculate the model, switch with to the solver menu. Because in this case we have

a very small structure, the direct Cholesky-Solver is a good choice. The stresses are eva-

luated by von Mises stresses.

starts the solver.

After successful calculation the results can be displayed in the postprocessor (

)

( Figure 3 ) . To view the tensile and compression stresses choose Stress per element . Be-

cause in trusses there are just tensile and compression stresses the displayed effective

stresses do only represent them.

Figure 3: Result screen

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Plik z chomika:

Inne pliki z tego folderu:

installguide_win.pdf (1676 KB)
picking.wmv (44517 KB)
view_modes.wmv (38824 KB)
quick_linear.wmv (32905 KB)
crane.pdf (599 KB)

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