This model shows the vertical symmetric half section of fiberglass ductwork. It was analysed for strength and buckling loads. The client needed to check the ductwork for design strength and in particular buckling loads so as to determine operational safety margins. FEA was chosen because of its predicative capability in complex loading situations combined with complex geometry. Non-linear analysis was used to predict the load that would cause the onset of buckling failure. The onset of buckling is shown as exaggerated deflection in the example. The example also shows laminate strength safety factors based on the Tsai-Hill criteria, a criterion similar in concept to the quadratic failure criteria used in isotropic materials, such as steel. The areas of low indicated safety factor are being used to direct maintenance personnel to sections of the duct where degradation of the laminate, due to the action of process chemicals, will be the most serious.

This 45m stack developed flange failure due to exposure to wind induced oscillations.

Using FEA it was possible to determine the stress points and modal frequency of the stack.