A PZT Based On-Line Updated Guided Wave - Gaussian Process Method for Crack Evaluation

An essential procedure for fatigue crack evaluation based on structural health monitoring is to establish the mapping relationship between structural health monitoring signal features and the crack length. However, crack evolution in aerospace structure is a complicated process affected by many condition factors, such as the temperature, mission load, structural boundary condition and material characteristic. These factors are coupled with each other and cause serious uncertainties to the crack evolution in the structure. Ordinary methods by mapping or calibration using a set of same structural specimens or simulation to achieve an average mapping result cannot provide accurate results to a specific structure monitored, since this structure inevitably has deviations from the average result. Aiming at solving this problem, an on-line updated guided wave Gaussian Process based evaluation method is proposed in this paper, which differs from the current Gaussian Process research in the way of model dynamic updating. The proposed method is verified on attachment lug structures, which is a kind of important connection part commonly used in aircrafts. The effectiveness of the proposed method is well demonstrated.