ANALYSIS AND FATIGUE: FATIGUE ANALYSIS

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 hazardous situation.

A sign that required Modal Analysis using FEA techniques to predict vibration and stress

Modal Analysis indicating stress levels and potential failure points