Method for determining creep parameter of material by fixed straight bar small specimen creep test

Abstract

The invention relates to a method for determining the creep parameter of a material by a fixed straight bar small specimen creep test. The method comprises the following steps: (1) acquiring a fixed straight bar small specimen creep displacement time curve of the material; (2) determining critical displacements of small and large deformation of a specimen; (3) dividing deformation stages on the creep displacement time curve to determine the deformation stage of steady-state creep; (4) when the steady-state creep appears in a small deformation stage, analyzing a creep displacement curve of thesmall deformation stage according to a beam bending theory to obtain the creep deformation parameter of the material; (5) when the steady-state creep appears in a large deformation stage, analyzing acreep displacement curve in the large deformation stage according to a global deformation theory to obtain the creep deformation parameter of the material. By analyzing the fixed straight bar small specimen creep displacement time curve in stages, the true creep parameter of the material can be obtained more accurately.

Description

technical field [0001] The invention relates to material creep, in particular to a method for determining material creep parameters by using a fixed-supported straight bar small sample creep test. Background technique [0002] Creep, also called creep, is the tendency of a solid material to slowly and permanently move or deform under the influence of stress. It occurs as a result of prolonged stress below the yield strength of the material. Creep will be more severe when the material is heated for a long time or near the melting point. Creep often increases with increasing temperature. The rate of this deformation is related to material properties, loading time, loading temperature and loading structural stress. [0003] In the chemical process and power generation industries, in order to obtain high energy utilization, the working temperature and working pressure of equipment and components are constantly increasing, and the working environment is becoming more and more ...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a method for determining the creep parameters of a material by using the creep test of a small sample of a fixed straight rod. The present invention can accurately determine the creep of the material by using different creep deformation theories for different deformation stages of the material. Variable parameters are used to solve the problem that the current creep parameters in the large deformation stage are determined by the beam bending theory with small deformation assumptions, which makes the determination of material creep parameters inaccurate.

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