Abstract: A method of assessing bolted joint integrity. A guided wave is sent through a structure containing at least one bolted joint. The guided wave that is subsequently propagated through the structure and interacted with the bolted joint is measured to obtain a measured result. At least one parameter of the guided wave after its travel through the structure, and after having been affected by a nonlinear acoustic behavior of the bolted joint, is analyzed. Either at least one guided wave parameter is compared to a wave propagation pattern of the bolted joint at a correct torque level, or variation of at least one guided wave parameter is compared, to determine changes in wave propagation time and/or wave propagation shape. An incorrect torque level of the bolted joint is inferred from any changes that are determined.

Abstract: A method and device for performing ultrasonic damage detection in a thin-wall structure using an array of embedded Piezoelectric Wafer Active Sensors (PWAS) for the transmission and reception of guided waves and a signal processing methodology based on the beamforming process. The beamforming signal processing has been adapted to the specifics of guided elastic waves traveling in thin-wall structures.