Elastic Wave-based Damage Detection Using Active Sensor Network

Though serving as competitive candidates to meet future challenges imposed on aeronautical vehicles, composite structures run a high risk of losing efficiency as a result of damage if without timely detection. Cost-effective and reliable damage detection techniques are therefore critical for the confident acceptance of composite structures. This book presents an elastic wave-based damage identification technique and an online structural health diagnosis system for in-service composite structures, based on investigation of propagation characteristics of guided elastic waves in beams and plates bearing damage, in particular Lamb waves in composite laminates with through-hole or delamination. Fundamental and mechanism studies encompass theoretical analysis, finite element simulation and experimental verification. Following a review of the state of the art in this field, the book introduces a signal processing technique, termed Digital Damage Fingerprints (DDF); an inverse identification algorithm using a feedforward artificial neural network (ANN); and an active sensor network technique based on a novel concept, Standard Sensor Unit (SSU).