Free vibration analysis of thin, tensioned, helically wrapped webs using Mindlin-Reissner finite element method

Abstract

Free vibration analysis of a thin tensioned web, wrapped around a reverser was studied. The effect of helix angle was considered. The eigen-problem was formed using finite elements and solved numerically. Design parameters such as tension, radius of cylinder, wrap angle, width of the web, lengths of non-wrapped web and helical wrap angle were studied. It was seen that the free edges cause a frequency clustering of the lateral-modes about the dominant longitudinal-mode. It was also seen that the effectiveness of the plate-shell junction to act as a stiff support depends on problem parameters. Eigenmodes with same mode-shape numbers are observed in symmetric and anti-symmetric fashion about the center of the plate, for configurations with equally long unwrapped sections. The results also showed that the first natural frequency is reduced at large helical angles for the parameters studied.