A method for checking accuracy of residual stress by xrd method and calculating method for shear stress

Abstract

The invention relates to an accuracy test and a shear stress calculation method for detecting residual stress by XRD method, which belong to the technical field of metal material detection methods, and are used for accuracy test and shear stress calculation of residual stress detected by XRD method. The present invention combines the basic theory of elastic mechanics to deduce that the residual stress detection results of the XRD method at different angles should obey the cosine function distribution, use the origin software to perform cosine function fitting on the residual stress detection results of 4 or more different angles, and compare the measurement results with the The deviation of the fitting results and the deviation of the fitting parameters give a method for checking the accuracy of the residual stress detection results of the XRD method, and the parameters and corresponding formulas obtained through the fitting provide a calculation method of the residual stress and shear stress. The invention first proposes the conclusion that the residual stress detection result of the XRD method should obey the distribution of the cosine function, which is a breakthrough to the existing theory and solves the existing problems in the detection of the residual stress of the metal material by the existing XRD method.

Description

technical field [0001] The invention relates to an XRD method for detecting the accuracy of residual stress and a method for calculating shear stress, belonging to the technical field of metal material detection methods. Background technique [0002] XRD is the abbreviation of X-ray diffraction, and the Chinese translation is X-ray diffraction. The XRD method can conduct X-ray diffraction on the material, analyze its diffraction pattern, and obtain information such as the composition of the material, the structure or shape of the atoms or molecules inside the material, and the use of XRD to detect the residual stress of metal materials is one of the applications of many XRD methods . In the process of using the XRD method to detect residual stress, it is inevitable that the test results will be unreliable due to the influence of materials, equipment and operations. At the same time, different reference crystal planes are used in the test process and different peak-finding m...

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Problems solved by technology

[0003] In addition, the detection results of the XRD method are relatively simple, and the plane residual stress state cannot be expressed

In particular, the principle is to measure the change of the interplanar distance under the stress state and obtain the magnitude of the positive residual stress along a certain direction on the surface of the material through certain calculations, so it is impossible to measure the shear stress that does not cause a change in the interplanar distance

Although it is mentioned in the national standard GB / T7004-2017 that after measuring τ in three directions xy calculation method, but it can only provide the value of the shear stress in one direction and cannot provide the distribution of the shear stress at different angles, and it is based on less data, so it is difficult to guarantee the credibility of the calculation results

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