E04: Cantilever Beam Eigenvalues

Owned by Gokhan Alkan (Unlicensed)
Last updated: Mar 11, 2019

A cantilever beam is subjected to its own weight. The span length is 80 inches. The steel beam has 2 x 2 inches square cross section. The weight density of the beam is 0.281 lb/in3. Determine the lowest three frequencies of the beam.

The model used as shown in the figure has 19 joints and 18 beam elements. The beam is fixed at joint 1. The program computes the nodal (joint) masses for the eigenvalue analysis.

The data used for the problem is:


Modulus of Elasticity = 30,000,000 psi
Span Length = 80 inch
A = 4 in2
I = 1.3333 in4
Weight Density = 0.281 lb/in3 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. 275.