Ultrasonic Lamb wave local circulation scanning probability reconstruction tomography method

Abstract

An ultrasonic Lamb wave local circulation scanning probability reconstruction tomography method includes following steps: (1) planning a detection zone and arranging a sensor array on a detection part; (2) selecting a Lamb wave modal and designing an excitation signal, and respectively collecting reference signals and damage signals relative to the sensor pairs; (3) dividing the detection zone to obtain a plurality of sectors, wherein several adjacent sectors are employed as a sub zone; (4) when detection in a sub zone is completed every time, clockwisely rotating the sub zone by a position of one sector to form a next cyclic detection sub zone; (5) performing data selection pre-processing, calculating an valid data length according to the distance among the sensor pairs and the modal speed of the selected Lamb wave; (6) performing local circulation probability reconstruction tomography calculation; and (7) finally performing data fusion and image splicing. The method is strong in anti-jamming capability, is high in precision, can effectively eliminate the influence of multiple faults and the like on the method, and can increase detection resolution rate in multi-fault damage.

Description

technical field [0001] The invention belongs to the field of mechanical structure health monitoring, and relates to an ultrasonic Lamb wave partial circular scanning probability reconstruction tomography method. Background technique [0002] Lamb wave is a kind of ultrasonic guided wave, which has the characteristics of high detection efficiency, weak attenuation, and sensitivity to damage in structures. It is regarded as the most potential damage detection method for plate and shell structures. In the implementation process, the sensor array is generally used to obtain the propagation signal of the Lamb wave in the structure, and the detection and evaluation of the damage can be realized by extracting the characteristic parameters sensitive to the fault. Probabilistic reconstruction tomography is an effective means of detecting structural damage. This method uses the signal difference between the reference signal and the real-time signal in the normal state as the characte...

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Problems solved by technology

[0004] The above method has the following defects: (1) It is difficult to eliminate the influence of external interference and electromagnetic interference in the detection area, which may easily cause misjudgment and missed judgment; (2) When there are multiple faults in the detection area, especially when the fault is close to the sensor, the fault It will have a great impact on the signals of multiple pairs of sensors, and it is easy to generate false faults in the detection results, which will affect the fault detection results; (3) The detection resolution is low, and it is difficult to use in engineering practice

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