Structural health monitoring of aircraft structures: development of a phased array system.
Date
2011-10-17
Authors
Rocha, Bruno Filipe Ferreira Graca
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Abstract
This work consisted in the research and development of a phased array embedded
system for Structural Health Monitoring (SHM) of aircraft structures. This system is
based on piezoelectric (PZT) transducers to excite fast propagating first symmetric Lamb
wave mode (S0) wavefronts. The intent of this research is to contribute for an increasing
safety and efficient operation of aircraft.
Currently applied ultrasound inspections to aircraft structures in operation, as a
conventional Non Destructive Tests and Evaluations (NDT&E) technique, were
reviewed. Such and the previous development of a Lamb wave based SHM system using
PZT transducers in a network configuration served as the basis and for comparison to the
phased array SHM system developed. Lamb waves’ propagation behaviour was carefully
analyzed and a linear PZT phased array SHM system was developed and experimentally
tested. The PZT phased array was applied to representative aircraft structural aluminum
panels, considering also the existence of structural reinforcements and joints. New
techniques, hardware and software, leading to automated damage detection and location,
were researched, developed and implemented.
Tests for damage detection and location were performed, with the introduction of
damages into the specimens being simulated by surface and through the thickness holes
and cuts. Damages with a maximum dimension of 1mm applied cumulatively to the
specimens subject to different boundary conditions were successfully detected and
located.
Description
Keywords
airframes, aircraft structures