OS-V: 0425 Clamped Thin Rhombic Plate
Test No. FV15 The behavior of distorted thin elements in normal modes analysis is examined using OptiStruct.
Figure 1. FE Model with Boundary Conditions and Loadcases
Model Files
Before you begin, copy the file(s) used in this problem
to your working directory.
Benchmark Model
The 4-node quad elements with 12x12 mesh configuration are used to model the thin rhombic plate. The x-translation, y-translation displacements, and z-rotational displacements are fixed for all of the nodes. In addition, the z-translation, x-rotational and y-rotational are fixed for the nodes along the four edges.
The material properties are:
- Property
- Value
- E
- 200 x 109 N/m2
- 0.3
- 8000 kg/m3
Modal Analysis Results
The frequency of each targeted mode is normalized with the closed form solution. If a closed form
solution is not available, the target values for H.O.E. are used instead. All
benchmarked results are normalized with target values.
f*- Closed form solution
| Mode 1 | Mode 2 | Mode 3 | |||
|---|---|---|---|---|---|
 |
|
 |
|||
f*CQUAD4 |
7.938 Hz 0.9798 |
f*CQUAD4 |
12.835 Hz 1.0079 |
f*CQUAD4 |
17.941 Hz 1.0182 |
| Mode 4 | Mode 5 | Mode 6 | |||
|---|---|---|---|---|---|
 |
|
 |
|||
f*CQUAD4 |
19.133 Hz 0.9629 |
f*CQUAD4 |
24.009 Hz 1.0339 |
f*CQUAD4 |
27.922 Hz 1.0036 |
Reference
NAFEMS R0015 - Selected benchmarks for natural frequency analysis