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Method for predicting relaxation life of spiral spring on basis of stress relaxation theory of temperature accelerating material

A helical spring and stress relaxation technology, which is applied in the field of predicting the relaxation life of helical springs based on the theory of temperature-accelerated material stress relaxation, can solve the problems of large artificial errors in measurement data, cumbersome procedures, and long experimental periods, so as to improve efficiency and predict accuracy High, reduce the effect of test cycle

Inactive Publication Date: 2012-06-20
TIANJIN UNIV
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  • Application Information

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Problems solved by technology

Although this method overcomes the shortcomings of the bending test method and the torsion test method, and can be tested in batches, the device is simple and economical, but this method requires multiple loading and unloading, the process is cumbersome, and the measurement data has large human errors. The cycle is long, and its disadvantages are also obvious

Method used

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  • Method for predicting relaxation life of spiral spring on basis of stress relaxation theory of temperature accelerating material
  • Method for predicting relaxation life of spiral spring on basis of stress relaxation theory of temperature accelerating material
  • Method for predicting relaxation life of spiral spring on basis of stress relaxation theory of temperature accelerating material

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Embodiment 1

[0039] In this embodiment, a helical compression spring wound with 60Si2Mn oil-quenched and tempered steel wire is used for testing, and the basic parameters of the spring are d=10mm, D=40mm, t=15mm, H 0 = 66mm.

[0040] Before the test, preheat the equipment for 3 hours to eliminate the influence of the thermal expansion of the fixture on the test. Five temperature points of 100°C, 120°C, 140°C, 160°C and 180°C were selected as the accelerated stress relaxation test temperature. Because the wire diameter of this helical spring is relatively thick, preheat the spring for 30 minutes before loading. After preheating, compress the spring at a compression speed of 2.7mm / min until the storage height H of the spring in actual use 1 = 51 mm. The stress relaxation time is 40h. The data points in the relaxation test are collected one minute, and this process is completed autonomously by the computer system.

[0041] At five temperature points of 100°C, 120°C, 140°C, 160°C and 180°...

Embodiment 2

[0052] The present embodiment adopts the helical compression spring of 65Mn oil quenching and tempering steel wire winding to carry out the test, and the basic parameters of the spring are d=6mm, D=25mm, t=8mm, H 0 =290mm.

[0053] Before the test, preheat the equipment for 3 hours to eliminate the influence of the thermal expansion of the fixture on the test. Five temperature points of 80°C, 100°C, 120°C, 140°C and 160°C were selected as the accelerated stress relaxation test temperature. Since the wire diameter of this coil spring is relatively thin, preheat the spring for 15 minutes before loading. After preheating, compress the spring at a compression speed of 6mm / min until the storage height H of the spring in actual use 1 =230mm. The stress relaxation time is 24h. The data points in the relaxation test are collected one minute, and this process is completed autonomously by the computer system.

[0054] At five temperature points of 80°C, 100°C, 120°C, 140°C and 160°...

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Abstract

The invention discloses a method for predicting the relaxation life of a spiral spring on the basis of the stress relaxation theory of a temperature accelerating material. The method comprises the following steps of: testing stress relaxation data of the spiral spring at test temperature and drawing a relaxation curve; drawing a semilogarithmic curve of load loss rate and time and fitting a regression equation; drawing a relation curve of relaxation factors A and B and temperature and fitting a regression equation; and calculating relaxation factors A (actual) and B (actual) of the spiral spring at an actual use temperature and calculating the relaxation life of the spiral spring. Compared with the traditional compression loading and unloading method, the method has the advantages that due to adoption of an RDL10 spring stress relaxation testing machine, errors are reduced and the accuracy is improved; and since a temperature accelerating mode is adopted for predicting the relaxation life of the spiral spring, the predication accuracy is higher, simultaneously the test period is greatly reduced, the efficiency is improved and the cost is lowered.

Description

technical field [0001] The invention relates to a method for predicting the relaxation life of a helical spring based on a temperature-accelerated material stress relaxation theory, which belongs to the technology for predicting the relaxation life of a spring. Background technique [0002] Stress relaxation refers to the process of transformation from pure elastic strain to inelastic strain in the material during the constant strain process, that is, ε e →ε p . Stress relaxation is a ubiquitous phenomenon. It is one of the failure forms of springs. As a basic part, springs are widely used in instrumentation devices, large-scale mechanical equipment and weaponry. Its stress relaxation process is It is manifested that its elasticity gradually decreases with the extension of time, and the load capacity gradually decreases, that is, it is compressed or stretched to the same size and cannot reach the load value achieved before stress relaxation. In terms of size, the free leng...

Claims

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Application Information

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IPC IPC(8): G01M5/00
Inventor 师春生尹西岳赵乃勤李家俊刘恩佐何春年
Owner TIANJIN UNIV
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