Abstract
Low velocity impact induces barely visible damage in the form of matrix cracking or delamination that can grow under hydro-thermo-mechanical loading and possibly lead to catastrophic failure if not detected at an early stage. A network of piezoelectric transducers can be used to monitor a structure over time for life prognosis through generation and sensing of guided ultrasonic waves. The aim of this study is to design and develop such a sensing method for damage assessment in a composite T-joint subjected to mechanical impacts. In this context, monitoring of Lamb waves in a carbon fiber reinforced polymer (CFRP) T-joint has been completed where dispersion and tuning curves have been obtained. Guided waves are transmitted into the structure through different specified pairs of surface-bonded lead-zirconate-titanate (PZT) transducers in a pitch-catch active structural health monitoring (SHM) approach. With these experiments, Lamb wave fundamental modes (A0 and S0) are identified for monitoring impact damage by signal comparison with a prior obtained baseline. Detecting 4J and 10J inner impacts within the central region of the specimen is challenging when using conventional non-destructive techniques (NDT) because of the complex geometry and interference with the web. Signals are compared for the same selected sensing path; and amplitude differences in dispersion curves have been observed after the 10J impact, which imply the occurrence of a structural change related to the impact.
Original language | English |
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Pages (from-to) | 1-13 |
Number of pages | 13 |
Journal | Aerospace |
Volume | 5 |
Issue number | 2 |
DOIs | |
Publication status | Published - 9 Apr 2018 |
Keywords
- composite
- T-joint
- SHM
- impact damage
- piezoelectric transducers
- lamb waves
Research Beacons, Institutes and Platforms
- National Graphene Institute