Mechanical wave measurement and gas excitation for bondline inspection

    公开(公告)号:US11493429B1

    公开(公告)日:2022-11-08

    申请号:US17371984

    申请日:2021-07-09

    Abstract: Systems and methods for bondline inspection using mechanical wave measurement and gas excitation. A cost-effective optical interferometry technique is used to measure mechanical waves generated by gas excitation, which measurements may be used to verify the strength of a bondline of a composite bonded structure. A gas gun which produces a high-pressure short-pulsewidth gas pulse at the front free surface of the composite material. A velocity interferometer system for any reflector (VISAR) is synchronized with the controlled gas pulsation and used to measure the surface velocities. The respective shock wave-induced displacements of the back and front free surfaces are then calculated. The measured free surface displacements are compared with calibrated thresholds to determine whether a weak bond has been detected or not. Optionally, a ring magnet is aligned exactly under the gas gun nozzle to enable VISAR beam centering.

    Active Temperature Compensation Technique for Structural Health Monitoring Sensors

    公开(公告)号:US20220390418A1

    公开(公告)日:2022-12-08

    申请号:US17702513

    申请日:2022-03-23

    Abstract: A system and method for detecting an anomaly in a structure using an adaptive filter to compensate for variations in piezoelectric transducer performance due to environmental factors such as temperature. A first voltage signal having a first amplitude is sent to a reference piezoelectric actuator. Thereafter, a first reference voltage signal is received from a reference piezoelectric receiver which is acoustically coupled to detect the guided wave generated by the reference piezoelectric actuator. A second amplitude is determined using an optimization algorithm of an adaptive filter to compensate for nonlinear behavior of the reference piezoelectric actuator and receiver based on the first reference voltage signal. Then the adaptive filter sends a second voltage signal having the second amplitude to the reference and test piezoelectric actuators. Reference and test voltage signals are received from the reference and test piezoelectric receivers in response to the second voltage signal. A difference voltage signal representing differences between the reference and test voltage signals received is then recorded.

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