Imperfect interface contact state nonlinear ultrasonic evaluation method based on micro texture

Abstract

The invention relates to an interface contact state nonlinear ultrasonic testing method which belongs to the nondestructive testing filed. The method comprises the following steps: determining the frequency and the periodicity of detection signals according to the size and the material performance of a test piece forming a contact interface; by applying different pressures to a rough interface, changing the contact state, and carrying out ultrasonic transmission detection test on the rough interface; by carrying out nonlinear least-squares approximation processing on testing data of the test,determining micro characteristic composite parameters of the interface, computing a first-order rigidity coefficient and a second-order rigidity coefficient which are used for expressing the characteristics of the rough interface, and realizing ultrasonic expression of the contact characteristics of different rough interfaces. In the invention, the nonlinear ultrasonic coefficients are adopted toexpress the contact characteristics of the interface, the nonlinear ultrasonic detection has higher sensitivity comparing with the linear ultrasonic; by combining the micro texture and the rigidity relation of the interface, the method enables the macroscopic property of the interaction of the ultrasonic and the contact interface to be associated with the microcosmic property of the contact surface, thereby evaluating contact states of different microcosmic interfaces.

Description

technical field [0001] The invention relates to a nonlinear ultrasonic detection method, in particular to a non-intact interface contact state nonlinear ultrasonic evaluation method based on microscopic morphology, which is used for evaluating the non-intact interface contact state and belongs to the technical field of non-destructive testing. Background technique [0002] As an intermediate medium for transmitting motion and deformation, interfaces widely exist in various engineering structures, such as bonded structures commonly used in aerospace, military, petrochemical and other fields, mechanical seals widely used in machinery and automobile industries, and machine tool machining. Hydrostatic guide rail oil film support for industrial use, etc. Since the properties of the interface and the combined material or structure are often different, the interface contact performance becomes a key factor affecting the macroscopic mechanical properties of the entire material or st...

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Problems solved by technology

None of the above studies considered the scattering of ultrasonic waves by the microscopic topography of the two contacting surfaces constituting the interface.

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