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High-order longitudinal wave guide measuring method of steel strand prestress

A measurement method and technology for steel strands, which are applied in the analysis of solids using sonic/ultrasonic/infrasonic waves, can solve the problem that the size of prestress cannot be measured quickly and accurately in-service, and achieve low labor intensity, convenient detection and high efficiency. Effect

Active Publication Date: 2009-05-27
BEIJING UNIV OF TECH
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Problems solved by technology

[0006] The purpose of the present invention is to solve the current situation that the prestress size applied in the prestressed steel strand cannot be measured quickly, accurately, and in service. In order to evaluate the health status and service life of the prestressed structure, a steel strand prestressed The high-order longitudinal guided wave measurement method

Method used

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  • High-order longitudinal wave guide measuring method of steel strand prestress
  • High-order longitudinal wave guide measuring method of steel strand prestress
  • High-order longitudinal wave guide measuring method of steel strand prestress

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Embodiment Construction

[0025] Provide the embodiment that following numerical simulation obtains in conjunction with the content of the inventive method:

[0026] (1) Install the excitation sensor 2 and the receiving sensor 3 in the same steel strand 1 with a distance of L 0 = 3.96m. In this embodiment, the steel strand has 7 cores, the nominal diameter is 17.80 mm, the diameter of the central steel wire is 6.30 mm, the diameter of the peripheral steel wire is 6.00 mm, and the pitch is 280 mm, then the propagation distance of the longitudinal mode in the peripheral steel wire is L = 3.96 × 280 2 + [ 2 π × 6.00 2 + 6.30 2 ...

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Abstract

The invention relates to high-order longitudinal guided-wave measurement method for steel strand prestress, belonging to non-destructive test field. High-order longitudinal mode of which group velocity is maximum at a frequency is selected for measuring the prestress loaded by the steel strand. At the frequency, the group velocity of the high-order longitudinal mode monotonically increases or reduces along with the tensile stress in the elastic deformation range of steel strand, and when the steel strand bears different prestress in the elastic deformation range of steel strand, the deviation value between the frequency value on the maximum value of high-order longitudinal mode group velocity and the initial frequency value of the longitudinal mode in free state is not more than 1%, and the error between the prestress value measured by the high-order longitudinal guided-wave and the actual value is not more than 1%. The invention solves the problems that the prestress applied to the steel strand can not be rapidly, precisely, and online measured.

Description

technical field [0001] The invention relates to a high-order longitudinal guided wave measurement method for steel strand prestress, and belongs to the technical field of non-destructive testing. Background technique [0002] Due to the advantages of saving materials, improving structural rigidity and fatigue resistance, prestressing technology is widely used in structures such as railway and highway bridges, foundation engineering and high-rise buildings. It is the fastest growing, most widely used, and most A science and technology with development potential. [0003] In the prestressed structure, high-strength steel bars are prestressed in the structure to improve its working condition, and are the main stress-bearing parts in the structure. Because of its large cross-sectional area, softness, and convenient construction and positioning, steel strands are the most widely used prestressed tendons at home and abroad. However, with the prolongation of the design life of pr...

Claims

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Application Information

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IPC IPC(8): G01N29/07
Inventor 刘增华何存富吴斌
Owner BEIJING UNIV OF TECH
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