# 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.

## 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
$\upsilon$
0.3
$\rho$
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

## Model Files

Refer to Access the Model Files to download the required model file(s).

The model file used in this problem includes:

fv5.fem

## Reference

NAFEMS R0015 - Selected benchmarks for natural frequency analysis