Modal frequencies of fiber-reinforced polymer pipes with wall-thinning using a wavelet-based finite element model

Abstract

Wall-thinning due to chemical reactions, heat, erosion, or a combination of such influences is the most dominant type of internal surface damage in piping systems. In order to examine the effect of wall-thinning on the natural frequencies, the elastodynamic model of the fiber-reinforced polymer pipe is formulated using a wavelet-based finite element method. In this context, a new set of Hermite shape functions is developed. The generalized eigen value problem is solved and the natural frequencies are obtained for an fiber-reinforced polymer pipe with different depths and locations of the wall-thinning. Moreover, the effect of wall-thinning on the modal frequencies of the pipe was verified experimentally. Both the analytical and experimental results demonstrate the potential of using vibration signature to detect internal surface damage in fiber-reinforced polymer pipes.