Leaky Lamb wave–based resin impregnation monitoring with noninvasive and integrated piezoelectric sensor network

Abstract

The propagation characteristics of leaky Lamb wave (LLW) when the rigid mold is loaded with water or viscous resin by one side are calculated numerically and verified experimentally, and the amplitude of A0 mode decreases linearly with the increase of liquid layer thickness. Then the valid applications of LLW in two- and three-dimensional resin flow monitoring of hand lay-up and VARI processes are carried out. The amplitude of A0 mode shows a downward trend in resin impregnation of both in-plane and through-thick directions, and the dry spots of different sizes could be identified. The amplitude and energy of received signals would decrease with the increase of resin coverage and the benchmark model of A0 mode is established and validated. The new wide sensing range measurement methods are proposed to effectively monitor the two- and three-dimensional resin flow front by the PZT sensor network in both noninvasive and integrated ways.