Characterisation of Lamb wave damage interactions for pseudo damage development

Abstract

In aeronautics delamination damage in composite structures are a crucial factor for the timing of maintenance cycles. Structural health monitoring systems based on ultrasonic guided waves have the potential to find them quickly and consequently save airlines money. For the development of such a system removable pseudo damage are a cost-efficient alternative to enable the necessary quantity of testing. However, to develop a removable pseudo damage, a strategy is needed to classify the wave interactions of delaminations in a way which can also be used to classify those of removable pseudo damage. Therefore, this paper will showcase a methodology to classify the Guided waves reflection, transmission and S0 to A0 mode conversions induced by delaminations and discuss potential pseudo damage types. The analysis is based on a b-scan taken by an air coupled ultrasonic scanner starting at the actuator and ending behind the damage. The key findings are that the suggested methodology was able to capture the wave interactions of the delaminations as well as the experimental pseudo damage. Thus, it could be used as a tool to test the interactions of pseudo damage and compare it to the ones of delamination. Hence, being the first step towards enabling high-volume damage localisation tests of structural health monitoring systems.