CN-122016137-A - Bolt multidirectional load measurement method and system based on array ultrasonic waves

CN122016137ACN 122016137 ACN122016137 ACN 122016137ACN-122016137-A

Abstract

The invention discloses a bolt multidirectional load measurement method and a system based on array ultrasonic waves, wherein the measurement method comprises the following steps of (1) measuring and calibrating axial load, linearly fitting longitudinal wave acoustic time differences of a central electrode under different axial loads, and establishing an axial load formula of the central electrode; the method comprises the steps of (1) detecting axial load of a bolt to be detected according to the formula, (2) identifying transverse load direction, fitting the functional relation between the angle of an edge electrode and the acoustic time difference as a sine function according to the acoustic time difference of the edge electrode under the action of the transverse load to be detected, obtaining the maximum value of the sine function, identifying transverse load direction according to the angle corresponding to the maximum value, (3) measuring and calibrating transverse load size, establishing a function of the difference of the maximum acoustic time difference and the transverse load according to the difference of the longitudinal wave acoustic time difference of a central electrode and the maximum longitudinal wave acoustic time difference, and detecting transverse load size, and calculating the transverse load of the bolt to be detected according to the function.

Inventors

LI WENBO
HUANG ZHIHONG
HU SHENG
JING XUECHAO
YANG BING
SUN LIPENG
MO JIAN
LU LING
ZHANG JUN
CHENG HU

Assignees

国网湖南省电力有限公司电力科学研究院
国网湖南省电力有限公司
国家电网有限公司

Dates

Publication Date: 20260512
Application Date: 20260225

Claims (6)

1. The utility model provides a multidirectional load measuring method of bolt based on array ultrasonic wave is provided with a center electrode and a plurality of marginal electrode on the terminal surface of waiting to examine the bolt, the center electrode set up in the central point of terminal surface puts, a plurality of marginal electrodes are the annular array and distribute along the edge of terminal surface, center electrode and marginal electrode all are connected with the sensor, and its characterized in that includes the following steps: (1) Measuring the axial load of the bolt; (1.1) a calibration process; (a1) Applying gradient axial load to the bolt to be detected, and recording longitudinal wave acoustic time difference of the central electrode under different axial loads; (a2) Performing linear fitting on longitudinal wave acoustic time differences of the central electrode under different axial loads, and establishing an axial load formula of the central electrode; (1.2) a measurement process; detecting the longitudinal wave acoustic time difference of a central electrode of the bolt to be detected to obtain an actual measurement value, and calculating to obtain the axial load of the bolt to be detected according to the axial load formula obtained in the step (a 2); (2) Identifying the transverse load direction of the bolt; (2.1) applying actual axial load and transverse load to the to-be-detected bolt to obtain acoustic time differences of edge electrodes with different angles, or rotating the to-be-detected bolt to fix angles and adding acoustic time difference measurement values with different directions; (2.2) analyzing the acoustic time difference data of the edge electrodes at all angles under the action of the transverse load to obtain that the acoustic time difference data of the edge electrodes in the circumferential direction shows a distribution rule of a sine function; (2.3) fitting the angle and acoustic time difference data of the edge electrode under the action of the transverse load according to a sine function to obtain a sine function of the angle and the acoustic time difference, obtaining a maximum value of the sine function according to the sine function of the angle and the acoustic time difference, and identifying the transverse load direction according to the angle corresponding to the maximum value; (3) Measuring the transverse load of the bolt; (3.1) a calibration process; (b1) Applying the same axial load to the bolt to be detected, then applying gradient transverse load to the bolt to be detected, and recording longitudinal wave acoustic time differences of the central electrode and the edge electrode under different transverse loads; (b2) According to the rule of the longitudinal wave acoustic time difference data of each edge electrode, namely the distribution rule of the sine function of the longitudinal wave acoustic time difference data of each edge electrode, after fitting, finding the maximum value of the sine function, and recording the maximum value as the maximum longitudinal wave acoustic time difference; (b3) Calculating the difference value of the longitudinal wave acoustic time difference and the maximum longitudinal wave acoustic time difference of the central electrode under different transverse loads, performing data fitting on the difference value and the transverse loads, and establishing a function of the maximum acoustic time difference value and the transverse loads; (3.2) actual measurement process; detecting the central electrode longitudinal wave acoustic time difference and the maximum longitudinal wave acoustic time difference of the bolt to be detected, calculating to obtain the difference value of the central electrode longitudinal wave acoustic time difference and the maximum longitudinal wave acoustic time difference, and calculating to obtain the transverse load of the bolt to be detected according to the function of the maximum acoustic time difference value and the transverse load obtained in the step (b 3).
2. The method for measuring the multidirectional load of the bolt based on the array ultrasonic waves according to claim 1, wherein the transverse load direction of the bolt is the position of an angle corresponding to the maximum value of the fitted sine function pointed by the central electrode.
3. The array ultrasonic wave-based bolt multidirectional load measurement method according to claim 1 or 2, wherein in step (a 2), the axial load formula of the center electrode is shown as formula (1); (1); In the formula (1), the components are as follows, The time difference of longitudinal wave sound of the central electrode is ns, For axial loading, in kN, 、 Is the calibration coefficient.
4. The method for measuring the multi-directional load of the bolt based on the array ultrasonic waves according to claim 1 or 2, wherein in the step (b 3), the function of the maximum difference in acoustic time and the lateral load is shown as formula (2); (2); In the formula (2), the amino acid sequence of the compound, The difference between the central electrode longitudinal wave acoustic time difference and the maximum longitudinal wave acoustic time difference is ns, Is a transverse load, in kN, 、、 Is the fitting coefficient.
5. An array ultrasonic wave based bolt multidirectional load measuring system for performing the array ultrasonic wave based bolt multidirectional load measuring method according to any one of claims 1 to 4, comprising: The central electrode longitudinal wave acoustic time difference acquisition unit is used for applying gradient axial load and transverse load to the bolt to be detected and recording longitudinal wave acoustic time differences of the central electrode under different axial loads and longitudinal wave acoustic time differences of the central electrode under different transverse loads; the edge electrode longitudinal wave acoustic time difference acquisition unit is used for applying gradient axial load and transverse load to the bolt to be detected and recording longitudinal wave acoustic time differences of the edge electrodes under different axial loads and longitudinal wave acoustic time differences of the edge electrodes under different transverse loads; The axial load formula acquisition unit is used for carrying out linear fitting on the longitudinal wave acoustic time difference of the central electrode under different axial loads to establish an axial load formula of the central electrode; The function obtaining unit of the maximum acoustic time difference and the transverse load finds the edge maximum longitudinal wave acoustic time difference according to the longitudinal wave acoustic time difference data rule of each edge electrode; The transverse load direction identification unit is used for fitting out a functional relation between the angle and the acoustic time difference according to the distribution rule of the acoustic time difference of each angle under the action of the transverse load, obtaining a maximum value of a sine function according to the functional relation between the angle and the acoustic time difference, and identifying the transverse load direction according to the angle corresponding to the maximum value; The axial/transverse load acquisition unit acquires the axial load of the bolt to be detected according to an axial load formula, and acquires the transverse load of the bolt to be detected according to a function of the maximum acoustic time difference value and the transverse load.
6. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the method for measuring a multi-directional load of a bolt based on an array longitudinal wave according to any one of claims 1 to 4.

Description

Bolt multidirectional load measurement method and system based on array ultrasonic waves Technical Field The invention belongs to the technical field of nondestructive testing, and particularly relates to a bolt multidirectional load measurement method and system based on array ultrasonic waves. Background The fastener of the hydroelectric generating set often bears irregular vibration, alternating load, impact load and other actions, so that the problems of fracture or loosening of bolts of the hydroelectric generating set are generated, the safe operation of the generating set is greatly influenced, and collapse accidents are caused in serious cases. Therefore, the high-precision measurement of the bolts is very necessary, the requirement of detecting the internal stress of the bolts in real time is met, and the operation reliability and safety of the hydroelectric generating set are enhanced. In the field of bolt stress measurement, early research at home and abroad has been advanced, wherein an ultrasonic method based on the acoustic elastic principle has been widely applied to axial load measurement, but relatively less research is performed in the transverse load direction. The traditional ultrasonic longitudinal wave method is mainly based on the mathematical relation between elastic stress and ultrasonic longitudinal wave and transverse wave sound velocity to detect bolts which are fastened and cannot be calibrated in longitudinal wave sound elasticity, but the method cannot effectively measure multidirectional loads. The current ultrasonic detection technology of the bolt is characterized in that a) only stress in one direction can be measured, only data in one sound time can be obtained, simultaneous measurement of the size and the direction of a single load cannot be carried out, simultaneous measurement of multi-directional loads of the bolt is not possible, the ultrasonic detection technology is limited to a scene with known load directions, such as a process of applying pretightening force to the bolt, but in the service process of a hydraulic turbine, complex alternating load is applied to the bolt by an external environment, so that a novel stress measurement method needs to be developed, b) a general ultrasonic probe is provided with only one electrode, the general ultrasonic probe is placed in the central area of the head or the bottom of the bolt during measurement, the central area of the bolt is not subjected to stretching and compression when the bolt is subjected to transverse load, and the size and the direction of the transverse load cannot be measured by the single central electrode in the ultrasonic sensor because the sound is almost unchanged when the transverse load is applied. Disclosure of Invention The invention aims to solve the technical problem of overcoming the defects of the prior art and providing a bolt multidirectional load measuring method and a system based on array ultrasonic waves. In order to solve the technical problems, the invention adopts the following technical scheme. A multi-directional load measuring method of a bolt based on array ultrasonic wave is provided with a center electrode and a plurality of edge electrodes on one end face of the bolt to be detected, the center electrode is arranged at the center position of the end face, the plurality of edge electrodes are distributed in a ring-shaped array along the edge of the end face, and the center electrode and the edge electrodes are connected with sensors, comprising the following steps: (1) Measuring the axial load of the bolt; (1.1) a calibration process; (a1) Applying gradient axial load to the bolt to be detected, and recording longitudinal wave acoustic time difference of the central electrode under different axial loads; (a2) Performing linear fitting on longitudinal wave acoustic time differences of the central electrode under different axial loads, and establishing an axial load formula of the central electrode; (1.2) a measurement process; detecting the longitudinal wave acoustic time difference of a central electrode of the bolt to be detected to obtain an actual measurement value, and calculating to obtain the axial load of the bolt to be detected according to the axial load formula obtained in the step (a 2); (2) Identifying the transverse load direction of the bolt; (2.1) applying actual axial load and transverse load to the to-be-detected bolt to obtain acoustic time differences of edge electrodes with different angles, or rotating the to-be-detected bolt to fix angles and adding acoustic time difference measurement values with different directions; (2.2) analyzing the acoustic time difference data of the edge electrodes at all angles under the action of the transverse load to obtain that the acoustic time difference data of the edge electrodes in the circumferential direction shows a distribution rule of a sine function; (2.3) fitting the angle and acoustic time difference data of the ed