HyperWorks Solvers

Cantilever with Off-Center Point Masses (Test No. FV4)

Cantilever with Off-Center Point Masses (Test No. FV4)

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Cantilever with Off-Center Point Masses (Test No. FV4)

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fv4

Summary

Test No. FV4 is a cantilever beam with off-center point masses. The problem is set up to test the behavior of coupling between torsional and flexural, off-center inertial axis, and close eigenvalues. OptiStruct is used in this normal modes analysis.

 

Benchmark Model

The 2-node simple beam elements are used to model the problem. The cantilever beam consists of five elements. Two rigid elements are used to connect mass 1, 10000 kg, and mass 2, 1000 kg, at the end of the cantilever beam. All degrees of freedom at end A are constrained. The material properties for the cantilever beam 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

Mode 2

Mode 3

fv4a

fv4b

fv4c

f*
CBAR

1.723 Hz
1.0054

f*
CBAR

1.727 Hz
1.0048

f*
CBAR

7.413 Hz
1.008

 

Mode 4

Mode 5

Mode 6

fv4d

fv4e

fv4f

f*
CBAR

9.972 Hz
1.0055

f*
CBAR

18.155 Hz
1.0067

f*
CBAR

26.957 Hz
1.0068

 

File Location

<install_directory>/demos/hwsolvers/optistruct/fv4.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.