Numerical modelling of scattered Lamb waves through varied damage size in challenging geometry

Abstract

Lamb waves have been accepted as a potential technology for damage detection. However, industry has not adopted the technology due to the fundamental nature of current studies. This article attempts to bring together several areas of knowledge to make a step towards adoption. Commonly, readings from damaged specimens are compared with baseline readings to establish damage. A quantitative approach (scatter calculation) is taken in this article to reveal areas or sensitivity and possible quantification of damage. This method is applied to displacement fields collected through laser vibrometry and numerical simulations. The numerical simulations are performed alongside to assess their usefulness and feasibility when paired with scatter calculations. Analysis of two specimens is presented here: an idealised flat plate and representative aircraft lower wing skin are progressively cut to investigate their response to damage. Despite similar crack-actuator placement in both specimens, the damage-sensitive areas are significantly impacted by geometry changes. This leads to a shift in optimal location of sensors and corresponding prospects of damage quantification.