Stress field measurement method based on ultrasonic tomography

Abstract

The invention provides a stress field measurement method based on ultrasonic tomography, which belongs to the technical field of ultrasonic nondestructive testing. The method comprises the steps of carrying out a calibration test; determining a projection coefficient matrix; zero-stress reference acquisition: sequentially exciting each ultrasonic transducer in an ultrasonic transducer array to obtain a zero-waveform data set; measurement data acquisition: sequentially exciting each ultrasonic transducer in the ultrasonic transducer array according to the excitation sequence of zero-stress reference acquisition to obtain a test waveform data set; carrying out delay calculation, and using a cross-correlation algorithm for solving to obtain a corresponding stress delay vector; solving a stress field equation, and solving the stress field equation by using a tomography algorithm to obtain a stress vector; and drawing a stress field image according to the stress vector. On the basis of theultrasonic tomography algorithm, a probe scanning matrix is constructed, so that the shallow surface stress field distribution of a workpiece can be obtained by single measurement without moving the probe, the requirement on an operator is reduced, and the measurement efficiency is improved.

Description

technical field [0001] The invention relates to a stress field measurement method based on ultrasonic tomography, belonging to the technical field of ultrasonic nondestructive testing. Background technique [0002] The material will inevitably produce plastic strain during the mechanical manufacturing process, resulting in residual stress. At the same time, during the service process of the workpiece, the interior of the workpiece is affected by aging or external loads, and the stress will change. Measuring the surface stress of the workpiece can not only provide data support for the safety evaluation of the structural service, but also improve the production process and component processing methods on this basis to further extend the service life of the workpiece and reduce production and operation costs. [0003] There are many kinds of stress detection technologies in objects, which can be subdivided into three categories according to whether the detected object is damage...

AI Technical Summary

Problems solved by technology

At the same time, the existing ultrasonic residual stress measurement technology adopts single-point measurement. To realize the stress distribution measurement on the shallow surface of the workpiece, a mechanical device is often used to move the measurement probe to realize the measurement of different measurement points. The quality of the operator is required to be high, so the rapid and non-destructive measurement of the stress field distribution on the shallow surface of the workpiece has great engineering application value

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