Test device and test method for measuring residual stress of bent pipe

Abstract

The invention relates to a test device and test method for measuring residual stress of a bent pipe and belongs to the technical field of experimental mechanics and residual stress measurement. In the method provided by the invention, the digital speckle correlation technique is combined with the drilling technique, and the method comprises the following steps: using a CCD (charge coupled device) camera to take photos of the bent pipe before and after the bent pipe is drilled; utilizing the digital speckle technique to measure the stretched displacement of two ends of the front and back drilled round holes; and measuring the residual stress of the bent test piece with a confirmed principal stress direction, so as to acquire the residual stress. The digital speckle correlation technique used in the method refers to non-contact measurement. Compared with the traditional electrical testing method, the method has the advantage that the complex process of sticking a foil gauge each time is omitted, thereby being more convenient and simpler. For the measurement of the residual stress of the bent pipe, a column correcting process is added in the method provided by the invention as compared with the traditional method, thus the acquired result is more accurate.

Description

technical field [0001] The invention relates to a device and method for measuring the residual stress of an elbow by combining digital speckle correlation and drilling technology, and belongs to the technical fields of experimental mechanics and residual stress detection. Background technique [0002] In the process of processing the bent pipe from the straight pipe, it will be subjected to various external forces and influences; when these external forces disappear, plastic deformation will occur in the component, and the influence of plastic deformation will prevent the external force from acting on the component. Completely disappear, there are still some effects and influences remaining in the component, so a large residual stress remains in the elbow. At present, the measurement of residual stress mainly uses the electric measurement drilling method. A hole is drilled on the component to be measured, so that the residual stress of the component around the hole is releas...

AI Technical Summary

Problems solved by technology

At present, the measurement of residual stress mainly uses the electric measurement drilling method. A hole is drilled on the component to be measured, so that the residual stress of the component around the hole is released, and the strain release is measured by the strain gauge, so as to reverse the residual stress value. , but this method needs to attach strain gauges for each measurement, and the process is more cumbersome

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