OS-V: 0415 Deep Simply-Supported Beam
Test No. FV5 OptiStruct tests the repeated eigenvalues, shear deformation, and rotary inertia. The possibility of missing extensional modes is also investigated.
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 2-node beam elements are used to model the simply-supported beam which consists of five elements. The displacements in x, y, and z direction, as well as the rotation in x direction are fixed at the end A. In addition, the displacements in y and z direction are constrained at end B.
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.
f*- Closed form solution.
| Modes 1 and 2 Flexural | Mode 3 Torsional | Mode 4 Extensional | |||
|---|---|---|---|---|---|
f*CBEAM 42.649 Hz |
42.649 Hz 1.0124 |
f*CBEAM 77.542 Hz |
77.542 Hz 0.9157 |
f*CBEAM |
125.00 Hz 1.0000 |
| Modes 5 and 6 Flexural | Mode 7 Torsional | Modes 8 and 9 Flexural | |||
|---|---|---|---|---|---|
f*CBEAM 42.649 Hz |
148.31 Hz 1.0409 |
f*CBEAM |
233.10 Hz 0.8840 |
f*CBEAM |
284.55 Hz 1.0725 |
Reference
NAFEMS R0015 - Selected benchmarks for natural frequency analysis