A Nonlinear Imaging Method for Fatigue Closed Cracks in Metallic Materials

Abstract

The invention discloses a non-linear imaging method for fatigue closed cracks of metal materials, comprising the following steps: A. Conduct phased array deployment and control on the test specimen; B. Data collection for all phased array elements and grouped array elements respectively; C. Calculate the acoustic kinetic energy corresponding to the phased array of all array elements and the acoustic kinetic energy corresponding to the phased array of grouped array elements, ...,; D. Calculating the distribution of nonlinear characterization parameters; E. Image the computed results of . The beneficial effect is that, since the detection can be completed by using ordinary phased array equipment, the detection cost is reduced; in addition, due to the data acquisition and data processing of the phased array of all array elements and grouped array elements, the detection accuracy is high And rapid positioning of metal fatigue damage, thereby improving the detection accuracy of early fatigue damage of metal materials; realizing rapid positioning and imaging detection of early fatigue damage of metal materials.

Description

technical field [0001] The invention relates to a nonlinear imaging method for early fatigue closed crack detection of metal materials. Background technique [0002] Under the repeated action of alternating loads, metal materials or structures will experience fatigue. Fatigue is the incremental process of localized, permanent damage occurring at a point in a material under cyclic loading. After sufficient stress or strain cycles, with the accumulation of fatigue damage, the material will produce fatigue microcracks (closed cracks), and the microcracks will further expand to macroscopic cracks until the component is completely broken, resulting in complete failure of the component or structure. This is the material The entire life cycle experienced during the fatigue failure process. Fatigue damage and fatigue cracks belong to the early stage of the material life cycle and occupy most of the life cycle. In actual engineering, when metal components are in the early stage of...

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Problems solved by technology

[0010] (2) Unable to locate, characterize and image early fatigue defects

[0011] (3) The system nonlinearity brought by the instrument itself will affect the actual judgment

[0019] (1) Qualification and imaging of early fatigue defects cannot be achieved

[0020] (2) The non-linear damage components are very small and difficult to extract, and the amplitude of the collected signal is very small, which cannot meet the requirements of detection and judgment. It is often necessary to use special signal processing methods to correct the ultrasonic signal, which requires high signal processing

[0021] (3) The system nonlinearity brought by the instrument itself will affect the actual judgment

[0028] (2) Data processing is very complex and time-consuming, and it is difficult to apply it to the actual rapid inspection site

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