A modelling technique to investigate the effects of quasi-static loads on guided-wave based structural health monitoring systems

Guided wave-based methods for damage detection have been widely investigated as techniques to identify damages and their dimensions in structures. Most of the research activities presented in literature have been performed focusing on simple case studies in a laboratory environment, whereas Structural Health Monitoring systems should be investigated under operational loading conditions. When subjected to an operational load, propagation mechanisms can change, suffering from the interaction between propagating signal and scattered waves due to an initial stress-strain state, and so leading to errors in damage sites estimation. In this work, a numerical model, based on Finite Element approach, is proposed to investigate the effects of an initial stressstrain state, induced by a quasi-static load, on guided-wave propagation mechanisms. The case study consists of a real structure, a blended winglet of a general aviation aircraft. The methodology was assessed with reference to different scenarios.