HyperWorks Solvers

Pin-ended Double Cross (Test No. FV2)

Pin-ended Double Cross (Test No. FV2)

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Pin-ended Double Cross (Test No. FV2)

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fv2

Summary

Test No. FV2 is a pin-ended double cross, in-plane vibration problem. OptiStruct is used to investigate the coupling between flexural and extensional behavior, as well as the repeated and closed eigenvalues of the double cross in normal modes analysis.

 

Benchmark Model

The 2-node simple beam elements are used to model the double cross. Each arm of the cross consists of four elements. The x- and y-translation displacements are fixed at the end of all arms. The material properties for the cross beams are:

E = 200x109 N/m2 and density = 8000 kg/m3

 

Modal Analysis Results

The frequency of each targeted mode is normalized with the closed form solution.

f* = closed form solution

Mode 1

Modes 2 and 3

Modes 4, 5, 6, 7 and 8

fv2a

fv2b

fv2c

f*
CBAR

11.336 Hz
0.9984

f*
CBAR

17.709 Hz
0.9958

f*
CBAR

17.709 Hz
0.9974

 

Mode 9

Modes 10 and 11

Modes 12, 13, 14, 15 and 16

fv2d

fv2e

fv2f

f*
CBAR

45.345 Hz
1.0000

f*
CBAR

57.390 Hz
0.9944

f*
CBAR

57.390 Hz
0.9999

 

File Location

<install_directory>/demos/hwsolvers/optistruct/fv2.fem

 

Reference

NAFEMS Ltd, The Standard NAFEMS BENCHMARKS TNSB Rev. 3, NAFEMS Ltd, Scottish Enterprise Technology Park, Whitworth Building, East Kilbride, Glasgow, United Kingdom, 1990.