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Uniaxial Stress Detection Method of Steel Strand Based on Ultrasonic Guided Wave Stress Sensitivity Analysis

A sensitivity analysis, ultrasonic guided wave technology, applied in the direction of measuring force, measuring devices, instruments, etc., can solve the problems of the complexity of the guided wave propagation mode, a large number of basic research and experimental research, and achieve easy data collection and testing process Simple, high-precision results

Active Publication Date: 2021-08-06
HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In terms of stress non-destructive testing, based on the theory of ultrasonic guided wave acoustoelasticity, for the ultrasonic guided wave propagating in the steel strand under the action of axial force, there is a certain correlation between the ultrasonic characteristic quantity and the axial stress. Due to the complexity of the mode, a lot of basic research and experimental research are still needed for the stress detection of in-service steel strand members by using ultrasonic guided waves

Method used

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  • Uniaxial Stress Detection Method of Steel Strand Based on Ultrasonic Guided Wave Stress Sensitivity Analysis
  • Uniaxial Stress Detection Method of Steel Strand Based on Ultrasonic Guided Wave Stress Sensitivity Analysis
  • Uniaxial Stress Detection Method of Steel Strand Based on Ultrasonic Guided Wave Stress Sensitivity Analysis

Examples

Experimental program
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Effect test

Embodiment 1

[0127] The present invention selects commonly used 7-wire steel strand duplicating specimen, taking the loading test of the B1 steel strand specimen as an example, the nominal diameter of the specimen is 15.20mm, the nominal cross-sectional area is 140mm, the length is 1057mm, and the tensile strength is 1057mm. It is 1860MPa. Detection was carried out according to the detection steps mentioned in Example 1.

[0128] The first step is to obtain the most stress-sensitive excitation frequency of the ultrasonic guided wave propagating in steel strands of the same diameter by using theory.

[0129] In the second step, the PZT piezoelectric film is pasted on the cross-section of the two ends of the steel strand to send and receive signals through the ultrasonic coupling agent, and the two ends of the steel strand are clamped by a special clamp for the steel strand with teeth. The wire has a good clamping effect. Before clamping, use the special aluminum skin for steel strands to w...

Embodiment 2

[0136] The present invention selects two different steel round bar test pieces: the first is HRB400 grade ribbed steel bar, and the second is 45# steel smooth round steel bar. The numbering and detailed parameters of the two kinds of steel round bar test pieces are shown in the table 2. Detection was carried out according to the detection steps mentioned in Example 1.

[0137] Table 2 Summary of parameters of steel round bar test piece

[0138]

[0139]

[0140] The first step is to obtain the most stress-sensitive excitation frequency of the ultrasonic guided wave propagating in a steel round rod with the same diameter by using theory.

[0141] In the second step, the PZT piezoelectric sheet is pasted on the cross-sections at both ends to send and receive signals through an ultrasonic coupling agent, and the fixing method is the same as that in Embodiment 1.

[0142]In the third step, since the yield strengths of the two steel round bar specimens are relatively close,...

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Abstract

The invention relates to a steel strand uniaxial stress detection method based on ultrasonic guided wave stress sensitivity analysis. Determine the optimal excitation frequency of the ultrasonic guided wave propagating in the duplicate test piece, and build the steel strand uniaxial stress detection hardware and software system, and obtain the relationship curve between the characteristic quantity of the ultrasonic guided wave and the stress at this frequency from the test; For the in-service steel strand components, determine the detection area, use the steel strand uniaxial stress detection system to obtain the ultrasonic guided wave time domain signal; process the captured time domain signal to obtain the measured ultrasonic guided wave feature, and It is substituted into the relationship curve between the characteristic quantity of the guided wave and the stress of the replicated test piece, and the uniaxial stress of the steel strand in service is obtained. The method of the invention can realize the non-destructive detection of the uniaxial stress of in-service steel strands and steel round rods of different specifications, and has high detection accuracy.

Description

technical field [0001] The invention belongs to the field of stress non-destructive testing of steel structural components, in particular to a steel strand uniaxial stress testing method based on ultrasonic guided wave stress sensitivity analysis. Background technique [0002] As a commonly used tension member, steel strand bears the main tension in the structure and is widely used in many fields of civil engineering. In the process of tensioning and in service, due to the performance degradation of building materials, complex construction conditions and the influence of environmental factors, the stress suffered by the steel strand will produce a certain degree of loss. In order to accurately understand and grasp the stress state and service performance of steel strands, it is necessary to develop an accurate, stable and efficient stress detection method for steel strands. [0003] The main application fields of steel strands include prestressed tendons in prestressed conc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L1/25
CPCG01L1/255
Inventor 李祚华王英瞩郑俊超滕军
Owner HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL