Patent ID: 11946735
Assignee: SOUTHWEST JIAOTONG UNIVERSITY
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 1:
2. The method for measuring the deviation angle of the fatigue microcrack based on the nonlinear ultrasound according to claim 1, wherein the step S4 specifically comprises:
S41: establishing a polar coordinate system on the surface of the metal plate with the center O of the microcrack as a polar point and the horizontal positive direction as a polar axis, wherein the orientation angle is that αx=x·Δα, and 0°≤αx<360°, and the number of change times of the orientation angle αx is that x=0, 1, 2, . . . , n;
S42: when the orientation angle αx satisfies that 0°≤αx≤180°, placing one excitation sensor at polar coordinates (r, αx) and one receiving sensor at polar coordinates (r, αx+180°); when the orientation angle αx satisfies that 180°<αx<360°, placing one excitation sensor at polar coordinates (r, αx) and one receiving sensor at polar coordinates (r, αx−180°); and forming an xth group of ultrasonic sensing paths between corresponding excitation sensor and receiving sensor, wherein r is a radius of the positive circumference drawn in the step S3;
S43: ultrasonically testing the xth group of ultrasonic sensing paths, wherein ultrasound is excited by the excitation sensor and collected by the receiving sensor to obtain time domain waveform signals of the xth group of ultrasonic sensing paths, and recording the time domain waveform signals formed by the xth group of ultrasonic sensing paths by an oscilloscope; and
S44: repeating the step S42 and the step S43 according to an order that the number of change times x of the orientation angle αx is increased from 0 to n in sequence to obtain n+1 groups of ultrasonic sensing paths in total, and recording n+1 groups of corresponding time domain waveform signals in total.