E03: Beam Eigenvalues
A simply supported beam is subjected to its own weight. The span length is 80 inches and the beam is steel with 2 inches square cross section. The mass density of the beam is 0.000728 lb-sec2/in4. Determine the fundamental frequency of the beam.
The model of the beam has 5 joints and 4 beam elements. Joints 1 and 5 are pin supports. The joints 2, 3 and 4 represent the lateral dynamic degrees of freedom.
Modulus of Elasticity = 30,000,000 psi
Span Length = 80 inches
A = 4 in2
Izz = 1.3333 in4
Weight Density = 0.281 lb/in2 g = 386 in/sec2
Tested Features
Sources
- LARSA 4D
- Thomson, W.T., "Vibration Theory and Application," Prentice-Hall, Inc., Englewood Cliffs, N.Y., 2nd Printing, 1965, p.18.
- Swanson Analysis Systems, Inc., "ANSYS Verification Manual".
Results Comparison
App Link:
Library Link:
https://openbrim.org/objid84jl4pxsn9jaol09lns71c.libobj
Model | Output Parameter | OpenBrIM | LARSA | Thomson | Swanson | OpenBrIM vs Larsa |
---|---|---|---|---|---|---|
Beam | f1(hz) | 28.76 | 28.76 | 28.77 | 28.77 | 1e-3% |