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CN-121994398-A - High-temperature-resistant intelligent bolt and stress detection method thereof

CN121994398ACN 121994398 ACN121994398 ACN 121994398ACN-121994398-A

Abstract

The invention relates to the technical field of nondestructive testing of intelligent fasteners, in particular to a high-temperature-resistant intelligent bolt and a stress detection method thereof. The bolt measuring end face is fixedly connected with an integrated chip through a couplant-free high-temperature welding process. The integrated chip is based on a specific cut piezoelectric material, the surface of the integrated chip is divided into an inner ultrasonic electrode and an outer resistance electrode through graphical etching, and dual-mode excitation and in-situ real-time temperature measurement of quasi-shear transverse waves and quasi-telescopic longitudinal waves are synchronously realized on a single chip. By combining with matched initial wave multiple cross-correlation alignment, frequency domain mapping acceleration and dynamic temperature compensation algorithms, the invention thoroughly solves the problems of failure of a coupling medium, large temperature measurement error, hardware time drift and the like of the traditional ultrasonic bolt under high temperature, and realizes high-precision and long-period dynamic monitoring of the bolt pretightening force under the extreme variable temperature working condition of up to 280 ℃.

Inventors

  • XING ZHANQIANG

Assignees

  • 中国工程物理研究院电子工程研究所

Dates

Publication Date
20260508
Application Date
20260410

Claims (10)

  1. 1. The high-temperature-resistant intelligent bolt stress detection method is characterized by comprising the following steps of: The method comprises the steps of directly welding a transverse-longitudinal wave and temperature sensing integrated chip on a bolt measuring end surface to form a solid-phase coupling interface without a coupling agent between the integrated chip and the bolt, wherein the integrated chip comprises a lithium niobate piezoelectric wafer and a patterned electrode arranged on the surface of the piezoelectric wafer, and the patterned electrode at least comprises an ultrasonic electrode for ultrasonic excitation and receiving and a resistance electrode for temperature measurement; Applying pulse excitation based on an ultrasonic electrode to enable the lithium niobate piezoelectric wafer to excite quasi-shear transverse waves and quasi-telescopic longitudinal waves simultaneously, and collecting transverse wave echo signals and longitudinal wave echo signals in a bolt; Performing initial wave alignment processing on the transverse wave echo signals and the longitudinal wave echo signals, and extracting acoustic time difference information of the transverse waves and the longitudinal waves; and carrying out temperature compensation on the acoustic time difference information by combining with the real-time temperature, and outputting a detection result of the tensile stress of the bolt based on the acoustic time difference information after the temperature compensation and a pre-calibrated stress fitting relation.
  2. 2. The method for detecting the stress of the high-temperature-resistant intelligent bolt according to claim 1, wherein the lithium niobate piezoelectric wafer is a 10 DEG rotated y-cut lithium niobate piezoelectric wafer, so that a quasi-shearing vibration mode and a quasi-stretching vibration mode are simultaneously obtained on a single piezoelectric wafer, and a quasi-shearing transverse wave and a quasi-stretching longitudinal wave are correspondingly excited.
  3. 3. The method for detecting the stress of the high-temperature-resistant intelligent bolt according to claim 1, wherein the resistance electrode is made of gold or platinum, and the resistance electrode is any one of annular, rectangular, snake-shaped or irregular shape, so that the integrated chip can realize the integrated integration of temperature measurement and ultrasonic detection on the same chip.
  4. 4. The method for detecting stress of a high-temperature-resistant intelligent bolt according to claim 1, wherein the step of collecting a transverse wave echo signal and a longitudinal wave echo signal in the bolt comprises the steps of: Filtering the transverse wave echo signal by adopting a first band-pass filtering frequency band; Filtering the longitudinal wave echo signals by adopting a second band-pass filtering frequency band; The first band-pass filtering frequency band and the second band-pass filtering frequency band are mutually distinguished to realize separation and extraction of transverse wave echoes and longitudinal wave echoes.
  5. 5. The method for detecting stress of a high-temperature-resistant intelligent bolt according to claim 1, wherein the initial wave alignment process comprises: And executing cross-correlation alignment processing for the initial waveform for 5 times, and aligning the initial waveform by combining excitation peak time so as to inhibit the influence of trigger time drift on the extraction of the acoustic time difference in the acquisition process.
  6. 6. The method for detecting stress of high-temperature-resistant intelligent bolts according to claim 5, wherein the cross-correlation alignment processing introduces frequency domain cross-correlation calculation based on convolution theorem, and the time complexity of the time domain cross-correlation is calculated by the following method Conversion to So as to improve the calculation efficiency of the acoustic time difference extraction.
  7. 7. The method for detecting stress of a high-temperature-resistant intelligent bolt according to claim 1, wherein the temperature compensation is performed on the acoustic time difference information, and the calculation formula is as follows: Wherein, the As the compensation amount of the acoustic time difference, For the temperature-time coefficient obtained by temperature calibration, For the said real-time temperature of the said temperature, For initial measurement of temperature.
  8. 8. High temperature resistant intelligent bolt, its characterized in that includes: A bolt body; The integrated chip is welded on the measuring end face of the bolt body, and comprises a lithium niobate piezoelectric wafer and a patterned electrode arranged on the surface of the piezoelectric wafer, wherein the patterned electrode at least comprises an ultrasonic electrode and a resistance electrode; The signal receiving and transmitting and collecting module is electrically connected with the ultrasonic electrode and the resistance electrode and is used for exciting the quasi-shear transverse wave and the quasi-telescopic longitudinal wave and collecting the transverse wave echo signals, the longitudinal wave echo signals and the resistance value of the resistance electrode; and the processing module is used for carrying out initial wave alignment on the transverse wave echo signals and the longitudinal wave echo signals to extract the acoustic time difference information, carrying out temperature compensation on the acoustic time difference information based on real-time temperature converted by the resistance value, and further outputting a bolt tensile stress detection result.
  9. 9. The high-temperature-resistant intelligent bolt according to claim 8, wherein the transverse-longitudinal wave and temperature sensing integrated chip is prepared by the following steps: providing a lithium niobate wafer, and depositing metal electrodes on the upper surface and the lower surface of the lithium niobate wafer; Dicing the wafer to obtain a piezoelectric chip; And performing patterned etching on the upper electrode of the piezoelectric wafer to enable the upper electrode to form an ultrasonic electrode and a resistance electrode which are electrically isolated from each other so as to obtain an integrated chip for transverse and longitudinal wave excitation/reception and temperature measurement.
  10. 10. The high temperature resistant intelligent bolt of claim 8, wherein the transverse and longitudinal wave and temperature sensing integrated chip comprises the following micro-assembly method: setting a multi-core miniaturized PCB substrate socket for electric connection on the measuring end face of the bolt; placing the integrated chip on a bolt measuring end surface, and directly welding the integrated chip and the bolt measuring end surface to form an acoustic connecting interface without a coupling agent; And correspondingly welding the electrode port of the integrated chip with the bonding pad port of the PCB substrate socket to realize electric connection.

Description

High-temperature-resistant intelligent bolt and stress detection method thereof Technical Field The invention relates to the technical field of nondestructive testing of intelligent fasteners, in particular to a high-temperature-resistant intelligent bolt and a stress detection method thereof. Background The bolt is used as the most basic and important fastening connecting piece in the industrial field and is widely applied to core key equipment such as aerospace, nuclear power equipment, petrochemical industry, large-scale power machinery and the like. In the long-term service process of the equipment, the equipment is usually subjected to extremely severe working condition environments such as high temperature, high pressure, strong vibration and the like, and the pretightening force state of the bolts is directly related to the running safety and reliability of the whole system. Among the pretightening force detection methods, the ultrasonic method is attracting attention because of its advantages of no damage, high precision, and on-line monitoring. The ultrasonic method is mainly used for inverting and calculating the axial stress by measuring the acoustic time variation of the acoustic wave propagating in the bolt. Because the sound wave propagation speed and the physical length of the bolt are obviously affected by the ambient temperature, the cross interference factors of the stress and the temperature are difficult to decouple by a single sound wave mode, the industry generally needs to acquire waveform data of two different sound speed characteristics of transverse waves and longitudinal waves at the same time to perform comprehensive judgment, and introduces real-time service temperature as a key parameter to perform accurate temperature compensation so as to realize high-precision dynamic measurement of the stress of the bolt in a complex variable-temperature environment. However, existing intelligent bolt ultrasonic detection technologies still face multiple challenges that are difficult to overcome when dealing with high temperature conditions. On one hand, the existing ultrasonic sensor is mostly bonded by adopting a normal-temperature acoustic couplant at an interface, the organic medium layer is extremely easy to age, volatilize and even thoroughly fail at high temperature, and cannot meet the physical connection requirement of long-duration high-temperature service, on the other hand, the existing single chip can only singly excite longitudinal waves, if double waves are required to be obtained, a plurality of chips with different cuts are required to be overlapped and combined, so that the whole structure of the sensor is swelling, serious acoustic interference is caused, in addition, in a temperature measurement link, the conventional scheme mainly relies on external attached thermocouples to obtain the ambient temperature, the in-situ real-time temperature inside a bolt is difficult to truly reflect, and moreover, an uncontrollable trigger time drift phenomenon exists in a hardware acquisition circuit in long-time continuous monitoring, so that serious deviation is unavoidable in the measurement and compensation result when the final sound is obtained. Disclosure of Invention The invention aims to provide a high-temperature-resistant intelligent bolt and a stress detection method thereof, which not only thoroughly solve the problems of interface high-temperature failure and temperature measurement hysteresis, but also eliminate time drift errors and realize high-precision dynamic management and control of high-temperature-resistant bolt stress by integrating transverse and longitudinal double wave excitation and in-situ temperature measurement through a single chip and combining a couplant-free high-temperature micro-assembly and initial wave alignment acceleration algorithm. The invention is realized by the following technical scheme: The method for detecting the stress of the high-temperature-resistant intelligent bolt comprises the following steps: The method comprises the steps of directly welding a transverse-longitudinal wave and temperature sensing integrated chip on a bolt measuring end surface to form a solid-phase coupling interface without a coupling agent between the integrated chip and the bolt, wherein the integrated chip comprises a lithium niobate piezoelectric wafer and a patterned electrode arranged on the surface of the piezoelectric wafer, and the patterned electrode at least comprises an ultrasonic electrode for ultrasonic excitation and receiving and a resistance electrode for temperature measurement; Applying pulse excitation based on an ultrasonic electrode to enable the lithium niobate piezoelectric wafer to excite quasi-shear transverse waves and quasi-telescopic longitudinal waves simultaneously, and collecting transverse wave echo signals and longitudinal wave echo signals in a bolt; Performing initial wave alignment processing on the transverse wave echo sig