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.

Active Publication Date: 2010-07-14
TIANJIN IRON & STEEL GRP
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The determination of false load reduction caused by temperature and the elimination of the influence of the false load reduction on the extrapolated value of the relaxation rate of the stress relaxation test have long been a problem in the field of stress relaxation detection.

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

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Effect test

no. 1 example

[0046] As the first embodiment of the present invention, when the stress relaxation test enters the stress relaxation plateau, the steps of judging whether the false load reduction caused by the temperature fluctuation of the test environment are as follows:

[0047] Analyze the stress relaxation time series. When the test enters the stable period of stress relaxation, if short-term frequent intensive unloading occurs, combine the test environment temperature sampling sequence and its corresponding time series to check whether the test environment temperature corresponding to the intensive unloading period has changed. , and then determine whether it is a false load reduction caused by the fluctuation of the test environment temperature.

[0048] As the second embodiment of the present invention, according to the geometric sequence relationship, these deloading times are redistributed to the time period between the previous deloading of the group of false deloading and the reap...

no. 5 example

[0069] As the fifth embodiment of the present invention, the false load shedding judgment module includes:

[0070] The temperature time analysis sub-module is used to obtain the test environment temperature sampling sequence and its corresponding time, and analyze the test environment temperature sampling sequence and its corresponding time.

[0071] The false load reduction judgment sub-module is used to determine whether the short-term frequent intensive load reduction that occurs after the test enters the stable stress relaxation period is a false load reduction caused by the temperature fluctuation of the test environment.

no. 6 example

[0072] As the sixth embodiment of the present invention, the off-load time allocation module includes:

[0073] The common ratio calculation sub-module is used for the calculation of the common ratio in the geometric sequence.

[0074] Unloading time redistribution sub-module, which is used to redistribute the unloading time to the time period between the previous unloading of a certain group of wrong unloading and the reappearance of unloading after this group of wrong unloading, and at the same time ensure that the unloading of this group The number of loads remains unchanged.

[0075] Figure 3-Figure 6 The results obtained by processing the data obtained from the 1000-hour stress relaxation test of a certain test sample are shown.

[0076] image 3 and Figure 4 It is the result of standard derivation on the original test data.

[0077] Figure 5 and Figure 6 It is the result derived from standard derivation after using the embodiment of the present invention to co...

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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.

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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Application Information

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IPC IPC(8): G01N3/00
Inventor 于明琪袁世强
Owner TIANJIN IRON & STEEL GRP
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