Validation of structural health monitoring techniques in a complex composite structure

Abstract

In recent years, aircraft parts manufacturing with composite materials is increasing. The possibility of applying Structural Health Monitoring (SHM) to this type of material is one of the most interesting techniques in Non- Destructive Inspection (NDI) nowadays. In addition, ultrasonic inspection and, particularly, Lamb waves, are a very useful tool, as it allows to analyze plate-like structures using Piezoelectric Transducers (PZT) to guide the wave. The generation, acquisition and processing of electric signals (which is interesting to perform it in an embedded electronicsystem), and the application of damage detection algorithms (in this case, it will be used delay-and-sum and RAPID algorithms, and a topological derivative approach), allow the assessment of the damage state of the structure without the information of the previous state (baseline). The sample to be analyzed is a complex multi-curved part of CFRP, in which 5 defects have been introduced artificially during the manufacturing process. The generation and acquisition of signals in various states of excitation (varying the amplitude of the signal) was carried out, obtaining significant values of difference between the signals of the same path (pitch-catch mode), in order to finally calculate the location of the damage.