Rapid ultrasonic dual-wave calibrated detection method for axial force of high strength bolt

A rapid ultrasonic dual-wave calibrated detection method for an axial force of a high strength bolt, comprising the following steps:

• S01:
• numbering a plurality of high strength bolts in a same detection region;
• S02:
• searching, in a database in equipment, a calibrated empirical value R0e of initial ratios R0 of ultrasonic transverse wave transit time to ultrasonic longitudinal wave transit time for each of the plurality of high strength bolts with entirely or partially same specification data in a zero stress state, or a calibrated empirical value ke of a slope k of variation of a bolt tension with a ratio of transverse wave transit time to longitudinal wave transit time for each of the plurality of high strength bolts with entirely or partially same specification data in a zero stress state;
• S03:
• measuring ratios Ri of the ultrasonic transverse wave transit time to the ultrasonic longitudinal wave transit time for the plurality of high strength bolts, using the ratios Ri to calculate an average value;
• S04:
• acquiring a nominal pretightening axial force value, using the nominal pretightening axial force value as an average value of tensions of the plurality of high strength bolts, and calculating a calibrated parameter ke′ or R0e′ according to assumptions implied in step S02 and S03 that the tension is a linear function to the average value of Ri;
• and
• S05:
• calculating axial forces of the high strength bolts according to the calibrated parameter a parameter combination of empirical R0e and calculated ke′ or a parameter combination of calculated R0e′ and empirical ke′.