Sensor Array Errors Quantification and Self- Calibration for Impact Damage Localization on Composite Structures Under Inconsistent Temperature Field

The superior performance of the array-processing algorithm relies on the accurate implementation of the steering vector, which must account for time shifts. Inconsistent temperature conditions can, however, impact the amplitude and arrival time of the Lamb wave, leading to inconsistent sensor array signals. Although error compensation and correction methods are required, it may not be necessary to compensate for every temperature condition. This study proposes an effective signal analysis technique and impact damage method. The proposed technique analyzes the array phase deviations and introduces a novel method to quantify the degree of array inconsistency at varying temperatures. First, the arrival time difference in the sensor array of the theoretical model and varying temperature conditions are fit. The angle between the resulting fitting lines is then taken as the inconsistency of sensor array errors. In addition, a novel self-calibration method for impact damage localization on composite structures is proposed. The calibration process involves reconstructing the covariance matrix with array errors as a Toeplitz matrix. The Rank Reduced-Multiple signal classification (MUSIC) (RARE-MUSIC) algorithm is then used to estimate the impact damage source, followed by the Weiss-Friendlander (WF) iterative algorithm to calculate the impact source location accurately. Experimental results show that the proposed method outperforms existing approaches in impact damage location under inconsistent temperature conditions, particularly when the temperature is between 60 °C to 80 °C, where the degree of inconsistency in sensor array errors is within 16.35° to 20.96°.