OS-V: 0450 Free Cylinder: Axi-symmetric Vibration

Test No. FV41 A free cylinder with axi-symmetric vibration. OptiStruct is used to investigate the rigid body mode, close eigenvalues, and the coupling between axial, radial and circumferential behavior.



図 1. FE Model with Boundary Conditions and Loadcases

Benchmark Model

The 1st order and 2nd order triangular axi-symmetric elements (CTAXI) are used to model the cylinder. The cylinder is unsupported.

The material properties are:
Property
Value
Young's Modulus
200 x 109 N/m2
Poisson's Ratio
0.3
Density
8000 kg/m3

Modal Analysis Results

Mode shapes predicted by OptiStruct.


図 2.
The frequency of each targeted mode is normalized with the NAFEMS closed form solution.
  Mode
  1 2 3 4 5 6
NAFEMS RBM 243.53 Hz 377.41 Hz 394.11 Hz 397.72 Hz 405.28 Hz
HOE (8×1) RBM 243.34 Hz 372.14 Hz 374.18 Hz 378.22 Hz 396.00 Hz
Normalized 1 1.000780801 1.014161337 1.053263135 1.051557295 1.023434343
HOE (16×3) RBM 243.46 Hz 377.15 Hz 393.2 Hz 394.6 Hz 400.97 Hz
Normalized 1 1.000287522 1.000689381 1.002314344 1.007906741 1.010748934
LOE (8×1) RBM 242.45 Hz 376.02 Hz 379.86 Hz 389.83 Hz 426.92 Hz
Normalized 1 1.004454527 1.003696612 1.037513821 1.020239592 0.949311346
LOE (16×3) RBM 243.28 Hz 377.69 Hz 391.42 Hz 395.54 Hz 423.00 Hz
Normalized 1 1.001027622 0.999258651 1.006872413 1.005511453 0.958108747

Model Files

必要なモデルファイルのダウンロードについては、モデルファイルへのアクセスを参照してください。

The model files used in this problem include:
  • FV41HOEC.fem
  • FV41HOEF.fem
  • FV41LOEC.fem
  • FV41LOEF.fem

Reference

NAFEMS R0015 - Selected benchmarks for natural frequency analysis