A Sensing System for Defects Detection in Reinforced Aluminium Panels by Ultrasonic Guided Waves Sensors

The new living modules of spacecrafts are made of reinforced aluminium panels of large dimensions and are eventually subjected to impacts with space debris causing damages. The defect detection presented in this paper is based on the design of piezopolymer interdigital transducers (IDT) based on an analytical model that predicts the optimal frequency and placement on the reinforced panel to avoid the influence of the reinforcing ribs on the ultrasonic guided wave propagation. The paper presents the experimental validation of the method on a representative panel with regular ribs distance of 10 cm and with IDT operating at 650 kHz. The layout of the sensing system is proposed to be integrated in a multichannel electronic system to demonstrate the feasibility for the applications in Structural Health Monitoring (SHM). Finally tests on standard surface defects are reported.