Method and system for correction of extrapolated value of relaxation rate in stress relaxation test

A technology of stress relaxation and stress relaxation time, applied in measurement devices, instruments, scientific instruments, etc., can solve the problems that plague the field of stress relaxation detection, and achieve the effect of improving confidence.
CN101776548AActive Publication Date: 2010-07-14TIANJIN IRON & STEEL GRP
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
TIANJIN IRON & STEEL GRP
Publication Date
2010-07-14

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Abstract

The invention belongs to the field of stress relaxation detection of prestressed steel products, in particular to a method and a system for the correction of an extrapolated value of a relaxation rate in a stress relaxation test. The method comprises the steps: inputting test parameters, and measuring and controlling the whole course of the stress relaxation test; recording the stress relaxation load reducing time and relaxation force accumulated values of test samples in real time, and obtaining test environmental temperature sampling records; allowing all stress relaxation test data to generate test data files; determining the load reduction error caused by the fluctuation of environmental temperature; re-allocating time of load reduction error; further fine-tuning the re-allocated time of load reduction error; carrying out 1000-hour relaxation rate extrapolation according to the method specified by standards; and outputting the extrapolation result. With the geometric progression comparison correction method, the invention can eliminate the impact of the load reduction generated by the fluctuation of the test environmental temperature in different test periods of time on the extrapolated value of the relaxation rate, and improve the confidence level of extrapolation, thereby solving the difficulties that beset the field of stress relaxation detection until now.
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Description

technical field

[0001] The invention belongs to the field of stress relaxation detection of prestressed steel products, in particular to a method and system for correcting the extrapolated value of the relaxation rate in a stress relaxation test. Background technique

[0002] Generally, the tensile stress relaxation test of prestressed steel products such as prestressed steel strands will take about 1-2 hours, and there will be an inflection point in the frequency of unloading; after 4 hours, it will enter a relatively stable period, and unloading will no longer be frequent. Through six consecutive years of research and experiments on low-relaxation prestressed steel strands in the spring and autumn seasons at an ambient temperature of about 20°C (without turning on the air conditioner to control the temperature), it was found that the test curves are basically smooth and approximate to power function curves.

[0003] After the test has been carried out for 10 hours, if freq...

Claims

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