Method for Determining the Critical Displacement of Bending Creep and Small Deformation of Small Specimen with Fastened Straight Rod

Abstract

The invention relates to a method for determining small deformation critical displacements of small sample bending creeps of clamped straight bars. The method comprises the following steps of: (1) establishing a finite element model and obtaining a creep displacement-time simulation curve; (2) dividing variable quantities of displacements and corners in a sample small deformation process into variable quantities in an elastic stage and variable quantities in a steady stage; (3) calculating maximum corner variable quantities in the elastic stage and the steady stage; (4) determining a theoretical creep time parameter value; (5) carrying out finite element simulation on a sample creep and correcting the theoretical creep time parameter to obtain a time correction coefficient; and (6) carrying out a creep test on a sample to obtain a creep displacement-time test curve, and calculating the corrected time parameter, wherein a displacement corresponding to the corrected time parameter is a critical displacement of the sample small deformation. The method is capable of correctly determining small deformation critical displacements of sample creeps and solving the problem that current small deformation critical displacement determination is incorrect.

Description

technical field [0001] The invention relates to material creep, in particular to a method for determining the critical displacement of small bending creep small deformation of a fixed straight rod small sample. Background technique [0002] Creep, also known as creep, is a phenomenon in which the strain of a solid material increases with time under the condition of keeping the stress constant. Due to creep, the stress state of a material at an instant is generally not only related to the instant deformation, but also related to the deformation process before the instant. Many engineering problems involve creep. Creep often increases with increasing temperature. The rate of this deformation is related to material properties, loading time, loading temperature and loading structural stress. In the chemical process and power generation industry, in order to obtain high energy utilization, the working temperature and working pressure of equipment and components are constantly ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for determining the critical displacement of the small creep deformation of a straight rod bending small sample. The present invention divides the displacement-time curve into an elastic stage and a steady state stage. After theoretical derivation and finite element correction, The critical displacement of small deformation can be accurately determined, which is used to solve the problem that the critical displacement of small deformation is determined only considering the span between the lower molds of the sample, which makes the determination of critical displacement of small deformation inaccurate

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