Three-dimensional optical profilometry method for testing multiple welding residual stress components

Abstract

The method of testing multiple welding residual stress components by three-dimensional optical profilometry, the pretreatment before welding; Cut in the middle section. XJTU-OM scans the cutting surface of the test plate to obtain the calculated measurement point cloud data; use the established data processing platform to perform normalization, denoising, displacement calculation, discrete, and boundary condition output on the point cloud data. Then, the stress calculation and analysis were carried out to obtain the longitudinal residual stress distribution of the primary cutting. The secondary cutting direction is perpendicular to the primary cutting direction and along the middle section, and the same scanning and data processing are performed on the profile of the cutting surface after the secondary cutting, and the stress calculation is performed using the profile data of the secondary cutting surface as the boundary condition, and the second Stress Elastic Calculation of Secondary Cut Surfaces. The invention has the advantage of having important theoretical and engineering values ​​for testing multiple residual stress components of welded parts.

Description

technical field [0001] The invention relates to the technical field of engineering measurement residual stress, in particular to a method for testing multiple welding residual stress components by three-dimensional optical profilometry. Background technique [0002] Since the development of residual stress testing, there have been dozens of testing methods for different working conditions, which are divided into mechanical (destructive) measurement methods and physical (non-destructive) measurement methods, each of which has its own advantages and disadvantages. Destructive methods include blind hole method, strip cutting method, elastic deformation method, etc. Among them, the small hole method is used more. The small hole release method is suitable for measuring welded components with large stress gradient changes due to its simple operation, and it is also suitable for measuring The advantages of small destructive components have been widely used in recent years, and it h...

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Problems solved by technology

However, both of these two commonly used methods measure the surface residual stress and cannot measure the internal residual stress of the workpiece.

Other internal residual stress testing methods, such as the layer-by-layer peeling method and the crack flexibility method, can measure the uniform residual stress distribution state of thick plates, but for welding residual stress fields with large stress gradient changes, they cannot accurately measure longitudinal stress and Transverse stress gradient, and complex and cumbersome, while the neutron diffraction method is too costly, time-consuming and limited to large-scale components

The contour method can only obtain the normal stress of the cut surface in a single cutting process, but the welding stress problem of thick plates often involves residual stress in multiple directions

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