OS-V: 0410 Cantilever with Off-Center Point Masses
Test No. FV4 This problem tests the behavior of coupling between torsional and flexural, off-center inertial axis, and close eigenvalues. OptiStruct is used in this normal modes analysis.
図 1. FE Model with Boundary Conditions and Loadcases
Model Files
開始前に、この問題で使用するファイルを作業ディレクトリにコピーしてください。
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:
- Property
- Value
- E
- 200 x 109 N/m2
- 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 | |||
|---|---|---|---|---|---|
|
|
|
|||
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 | |||
|---|---|---|---|---|---|
|
|
|
|||
f*CBAR |
9.972 Hz 1.0055 |
f*CBAR |
18.155 Hz 1.0067 |
f*CBAR |
26.957 Hz 1.0068 |
Reference
NAFEMS R0015 - Selected benchmarks for natural frequency analysis