Material stress detection technology based on changes of wavelength of supersonic waves

Abstract

The invention relates to a material stress detection technology based on changes of the wavelength of supersonic waves, belonging to the field of nondestructive test. The principles of acoustic elasticity of supersonic waves are employed in the invention; i.e., propagation velocity c in a material is influenced by stress in the material to a certain extent, the propagation velocity c and wavelength v are directly proportional according to the equation of v=c / f when frequency f is constant, changes of wavelength can be acquired by detecting phases arriving at a same point through a same path, so changes of acoustic velocity can be acquired, and the variation amount of stress can be eventually acquired. Compared with traditional ultrasonic measurement methods for stress, the material stress detection technology provided by the invention has the advantages of high instantaneity of measurement, applicability to on-line detection and transient detection of stress, small dynamic errors and high measurement precision.

Description

technical field [0001] The invention belongs to the field of non-destructive testing and relates to a material stress testing technology based on ultrasonic wavelength change. Background technique [0002] Ultrasonic testing is the most widely used, most frequently used and fast-growing non-destructive testing technology at home and abroad, and has become one of the most commonly used methods for non-destructive testing and evaluation of materials and structures. It is a non-destructive testing method that will not cause damage to components and will not pollute the external environment. The ultrasonic penetrating ability is strong, and it can measure the surface residual stress and internal stress of the component at the same time. Ultrasonic sensors are used to transmit and receive ultrasonic waves, which has low requirements on the surface quality of components and can realize non-contact measurement. Ultrasound is less affected by the environment, with fast detection s...

AI Technical Summary

Problems solved by technology

[0003] In the traditional ultrasonic stress detection method, the time difference method is used to characterize the relationship between the propagation velocity and the stress. However, the propagation velocity is usually very large, resulting in a very small difference in the sound propagation time under different stresses at the same distance, and a higher sampling rate is required. And h=ct, when h is fixed, c is usually measured by detecting the variation △t of time t, but the speed of c is larger, the change of t is smaller, and the sampling rate is higher, because h / △t∝c, so Conventional methods have large dynamic errors

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