ANALYSIS AND FATIGUE: FATIGUE
Although simplified "cookbook" methods
for fatigue analysis work for simple cases, the bewildering complexity
of many structural systems can result in complex vibration problems.
Finite Element Analysis is an effective tool for these cases. Designing
systems so that natural frequencies are not matched by anticipated
excitation frequencies is often critically important.
A design called for a sign to be cantilevered
out over the parapet wall of a building. HGC Engineering assissted
the structural engineers with modal analysis using Finite Element
Analysis techniques of the preliminary design concept. The analysis
revealed that the design was prone to a torsional vibration mode
which could place substantial stress in the supporting members under
a gusty wind, or cause the sign to impact the parapet wall.
Further analysis revealed that fatigue problems
at some of the joints could easily develop, leading to a potentially
A sign that required Modal Analysis using FEA
techniques to predict vibration and stress
Modal Analysis indicating stress levels and potential