A simply supported beam is analyzed to determine the fundamental frequency. Determine the fundamental frequency.

Analysis Type

2-D eigenvalue analysis (X-Z plan)

Unit System

in, lbf

Dimension

Length 80in

Element

Beam element

Material

Modulus of elasticity E = 30.0×10^6psi

Weight density γ = 0.281 lbf/in^3

Sectional Property

Rectangular cross-section: b = 2 in, h = 2 in

Boundary Condition

Node 1, 5: Constrain DX and DZ

Analysis Case

Eigenvalue analysis

App

Library

References

Thomson, W. T., (1965). “Vibration Theory and Application”, Prentice Hall, Englewood Cliffs, N. J.

Theoretical

MIDAS

OpenBrim

Percent Difference

(MIDAS vs Theoretical)

Percent Difference

(OpenBrim vs Theoretical)

Mode 1

Frequency (Hz)

28.766

28.759

28.7451

0.02%

0.07%

Period (sec)

0.0348

0.035

0.0348

0.6%

0%

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