CN-121977735-A - Bolt axial force detection method and system based on ultrasonic waves

CN121977735ACN 121977735 ACN121977735 ACN 121977735ACN-121977735-A

Abstract

The invention discloses a bolt axial force detection method and system based on ultrasonic waves, wherein a piezoelectric ceramic plate is sequentially fixed on one end face of a bolt to be detected in a free state and a fastening state, the piezoelectric ceramic plate is configured to excite and receive ultrasonic body waves in a single mode at the same time, ultrasonic pulses are emitted into the bolt to be detected through the piezoelectric ceramic plate, ultrasonic echo signals reflected by an internal structure of the bolt to be detected in the free state and the fastening state are respectively received, first waveform data and second waveform data are obtained, corresponding single reflection echoes are respectively determined from the first waveform data and the second waveform data, first acoustic time and second acoustic time of the bolt to be detected are respectively determined from the corresponding single reflection echoes, stress coefficients of the bolt to be detected in the fastening state are determined, and bolt axial force of the bolt to be detected is determined based on the stress coefficients of the bolt to be detected, the first acoustic time and the second acoustic time. According to the invention, the axial force of the bolt is accurately detected by a piezoelectric ultrasonic technology.

Inventors

LI RENTANG
CHEN CHAOLEI
LU YI
NIU QIANG
CHENG LEI
SONG LIN

Assignees

龙源(北京)新能源工程技术有限公司
龙源(西安)新能源工程技术有限公司

Dates

Publication Date: 20260505
Application Date: 20251226

Claims (10)

1. The ultrasonic bolt shaft force detection method is characterized by comprising the following steps of: s100, sequentially fixing a piezoelectric ceramic plate on the end face of one side of a bolt to be tested in a free and fastening state, and configuring the piezoelectric ceramic plate to excite and receive ultrasonic bulk waves of a single mode at the same time; S200, transmitting ultrasonic pulses into a bolt to be tested through a piezoelectric ceramic plate, and respectively receiving ultrasonic echo signals reflected by the internal structure of the bolt to be tested in free and fastening states to obtain first waveform data and second waveform data; S300, determining corresponding single reflection echoes from the first waveform data and the second waveform data respectively, and determining a first sound time and a second sound time of the bolt to be tested from the corresponding single reflection echoes respectively; S400, determining a stress coefficient of the bolt to be tested in a fastening state, and determining the bolt axial force of the bolt to be tested based on the stress coefficient of the bolt to be tested, the first sound and the second sound.
2. The ultrasonic-based bolt shaft force detection method according to claim 1, wherein the single-mode ultrasonic body wave is a longitudinal wave.
3. The ultrasonic-based bolt shaft force detection method according to claim 1, wherein the ultrasonic pulse drives the piezoelectric ceramic plate to emit into the bolt to be detected through the excitation circuit.
4. The ultrasonic-based bolt shaft force detection method according to claim 1, wherein the single reflection echo determination method is as follows: Acquiring first waveform data and second waveform data, and preprocessing the first waveform data and the second waveform data; Determining the length of a bolt to be detected and the sound velocity of ultrasonic waves of the bolt to be detected in free and fastening states, analyzing based on the length and the sound velocity, and determining the occurrence interval of the corresponding single reflection echo on a time axis; And respectively carrying out characteristic analysis on the preprocessed first waveform data and the preprocessed second waveform data in the corresponding occurrence intervals, and respectively determining a first echo signal with characteristics meeting the corresponding preset form and the preset amplitude condition as a single reflection echo of the first waveform data and the second waveform data.
5. The method according to claim 1, wherein in the step S200, the temperature of the bolt to be measured when the first waveform data and the second waveform data are obtained is measured and recorded simultaneously, and the first sound time and the second sound time are corrected to the same reference temperature before the calculation in the step S400.
6. The ultrasonic-based bolt shaft force detection method according to claim 1, wherein the first sound and the second sound determining method are as follows: Determining a first zero crossing point from a negative value to a positive value from the corresponding single reflection echo of the first waveform data and the second waveform data, and determining a starting moment point of a transmitting pulse in the corresponding single reflection echo; and respectively determining the time interval from the starting moment to the corresponding first zero crossing point as the first sound time and the second sound time of the bolt to be tested.
7. The ultrasonic-based bolt shaft force detection method according to claim 1, wherein the stress coefficient determination method is as follows: The axial force calibration experiment is carried out on sample bolts with the same batch and the same specification as the bolts to be tested, the experimental results are fitted, and the slope of the force-acoustic time-varying relation curve obtained by fitting is used as the stress coefficient of the bolts to be tested.
8. The ultrasonic-based bolt shaft force detection method according to claim 1, wherein the determining the bolt shaft force of the bolt to be detected based on the stress coefficient of the bolt to be detected, the first sound and the second sound comprises: And determining the sound time variation of the bolt to be tested according to the second sound time and the first sound time of the bolt to be tested, and calculating based on the stress coefficient and the sound time variation of the bolt to be tested to obtain the bolt axial force of the bolt to be tested.
9. The ultrasonic-based bolt shaft force detection method according to claim 8, wherein the calculation formula of the acoustic time variation of the bolt to be detected is: Δt=T2-T1, Wherein deltat is the sound time variation of the bolt to be detected, T2 is the second sound, and T1 is the first sound; the calculation formula of the bolt shaft force of the bolt to be measured is as follows: F=K*Δt, wherein F is the bolt axial force of the bolt to be tested, K is the stress coefficient of the bolt to be tested, and Deltat is the acoustic variation.
10. A bolt shaft force detecting system based on ultrasonic wave is characterized by comprising The piezoelectric sensing module comprises a piezoelectric ceramic piece and a fixing clamp thereof; the excitation and acquisition module is used for driving the piezoelectric ceramic plate to emit ultrasonic pulses and acquiring reflected ultrasonic echo signals; The signal processing module is used for determining a corresponding single reflection echo from the first waveform data and the second waveform data; and the calculation output module is used for calculating stress coefficients, the first sound time and the second sound time and calculating axial force and outputting the axial force.

Description

Bolt axial force detection method and system based on ultrasonic waves Technical Field The invention relates to the technical field of bolts, in particular to a bolt axial force detection method and system based on ultrasonic waves. Background In modern high-end equipment manufacturing and major engineering structures, high-strength bolting is a lifeline that ensures the safety and reliability of the overall structure. The core is to apply and maintain an accurate axial preload. The insufficient axial force can lead to loose connection and cause catastrophic accidents, and the excessive axial force can lead to bolt yielding or fatigue fracture. Therefore, accurate and reliable detection and monitoring of the bolt shaft force is a key link of quality control and predictive maintenance. The traditional bolt shaft force control method mainly relies on a torque method or a hydraulic stretching method. The torque method indirectly estimates the axial force by controlling the tightening torque, but the accuracy is severely limited by the friction coefficient of the screw pair and the supporting surface, the dispersion is higher, and the requirement of high reliability cannot be met. Although the hydraulic stretching method is more direct, the device is heavy, the operation is complex, and the hydraulic stretching method cannot be used for in-service inspection after fastening. Disclosure of Invention In order to solve the technical problems, the invention provides a bolt axial force detection method and a bolt axial force detection system based on ultrasonic waves, wherein the bolt axial force detection method comprises the following steps: s100, sequentially fixing a piezoelectric ceramic plate on the end face of one side of a bolt to be tested in a free and fastening state, and configuring the piezoelectric ceramic plate to excite and receive ultrasonic bulk waves of a single mode at the same time; S200, transmitting ultrasonic pulses into a bolt to be tested through a piezoelectric ceramic plate, and respectively receiving ultrasonic echo signals reflected by the internal structure of the bolt to be tested in free and fastening states to obtain first waveform data and second waveform data; S300, determining corresponding single reflection echoes from the first waveform data and the second waveform data respectively, and determining a first sound time and a second sound time of the bolt to be tested from the corresponding single reflection echoes respectively; S400, determining a stress coefficient of the bolt to be tested in a fastening state, and determining the bolt axial force of the bolt to be tested based on the stress coefficient of the bolt to be tested, the first sound and the second sound. Further, the single-mode ultrasonic bulk wave is a longitudinal wave. Furthermore, the ultrasonic pulse drives the piezoelectric ceramic plate to emit into the bolt to be tested through the excitation circuit. Further, the method for determining the single reflection echo comprises the following steps: Acquiring first waveform data and second waveform data, and preprocessing the first waveform data and the second waveform data; Determining the length of a bolt to be detected and the sound velocity of ultrasonic waves of the bolt to be detected in free and fastening states, analyzing based on the length and the sound velocity, and determining the occurrence interval of the corresponding single reflection echo on a time axis; And respectively carrying out characteristic analysis on the preprocessed first waveform data and the preprocessed second waveform data in the corresponding occurrence intervals, and respectively determining a first echo signal with characteristics meeting the corresponding preset form and the preset amplitude condition as a single reflection echo of the first waveform data and the second waveform data. Further, in step S200, the temperature of the bolt to be measured when the first waveform data and the second waveform data are obtained is synchronously measured and recorded, and before the calculation in step S400 is performed, the first sound time and the second sound time are corrected to the same reference temperature. Further, the method for determining the first sound and the second sound comprises the following steps: Determining a first zero crossing point from a negative value to a positive value from the corresponding single reflection echo of the first waveform data and the second waveform data, and determining a starting moment point of a transmitting pulse in the corresponding single reflection echo; and respectively determining the time interval from the starting moment to the corresponding first zero crossing point as the first sound time and the second sound time of the bolt to be tested. Further, the method for determining the stress coefficient comprises the following steps: The axial force calibration experiment is carried out on sample bolts with the same batch and the same s