OS-V: 0420 Free Thin Square Plate
Test No. FV12 A thin square plate model, which contains three rigid body modes. OptiStruct investigates the repeated eigenvalues and kinematically incomplete suppressions of the thin plate in Normal Modes Analysis.

Figure 1.
Benchmark Model
The 4-node quad elements with 8x8 mesh configuration are used to model the plate. The x-translation, y-translation displacements and z-rotational displacements are fixed for all nodes.
- E
- 200 x 109 N/m2
- 0.3
- 8000 kg/m3
Modal Analysis Results
f*
- Closed form solution
Mode 4 | Mode 5 | Mode 6 | |||
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f* CQUAD4 |
1.622 Hz 0.9964 |
f* CQUAD4 |
2.360 Hz 1.0145 |
f* CQUAD4 |
2.922 Hz 1.0231 |
Modes 7 and 8 | Mode 9 | Mode 10 | |||
---|---|---|---|---|---|
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f* CQUAD4 |
4.233 Hz 0.9978 |
f* CQUAD4 |
7.416 Hz 1.0496 |
F[HOE] CQUAD4 |
7.392 Hz 1.1746 |
Model Files
- <install_directory>/hwsolvers/demos/optistruct/verification/fv12.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.