A method for detecting the width of micro-cracks on the surface of materials
A detection method, a technology of microcracks, applied in the direction of analyzing materials, using sound waves/ultrasonic waves/infrasonic waves for material analysis, measuring devices, etc.
Active Publication Date: 2018-12-07
BEIJING UNIV OF TECH
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Problems solved by technology
[0004] The purpose of the present invention is to solve the problem of detection of micro-cracks on the surface of materials by line-focused ultrasonic transducers, and propose a detection method for crack width
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[0027] Step 1): Selection of material and size parameters of finite element analysis model
[0028] Combining the actual and theoretical analysis, it is obtained: in order to increase the bandwidth characteristics of the transducer and improve the energy transmission efficiency, the model selects a 40μm thick piezoelectric material PVDF film as the excitation / receiving element, Tungsten loaded epoxy, 10% vf5.8Mray1 (referred to as back10) As the backing, water was selected as the coupling fluid, the material to be tested was aluminum, and a line focusing transducer model was formed, and the transducer focusing radius was 20 mm. The material properties are shown in Table 1.
[0029] Table 1 Model material properties
[0030]
[0031] Step 2): Establishment of finite element analysis model
[0032] Line-focused ultrasound transducers based on PVDF, such as figure 1 As shown in the figure, the whole piezoelectric film is divided to establish a finite element model of a dual...
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The present invention discloses a detection method for detecting the width of a micro-crack on the surface of a material and belongs to the technical field of the non-destructive testing technology. The research on the detection method for detecting the width of the micro-crack on the surface of the material not only has important research significance on the material integrity evaluation, but also has important application value for the structure healthy and safety monitoring operation. According to the method, a dual-channel-line focused ultrasonic transducer model is established, and reception signals at different crack widths are analyzed. In this way, the method is an effective method for detecting micro-cracks on the surface of the material. The result of the method shows that, along with the width increasing of a crack, echo signals received by a channel 1 regularly change. Based on the above result, the detection and the quantitative characterization for the width of the micro-crack on the surface of the material can be realized. According to the method, the interference of a directly reflected echo on received signals on the surface of the material can be eliminated. Therefore, the defect-related information can be better extracted out of the received signals. The position of the micro-crack on the surface of the material can be detected, and the quantitative characterization for the width of the micro-crack on the surface of the material can be realized.
Description
technical field [0001] The invention designs a method for detecting the width of micro-cracks on the material surface based on PZFlex simulation software. The method is mainly used for the detection of micro-crack defects on the surface of small specimen materials by a line focused ultrasonic microscopic system, and belongs to the technical field of non-destructive testing. Background technique [0002] With the continuous development of materials science, various functional materials are emerging and put into use. During the service process of materials, cracks are prone to occur due to the action of stress. Cracks can be divided into two types: micro-cracks and macro-cracks. The cracks that have formed will continue to grow under the action of stress or environment (or both), a process called crack propagation. The appearance and expansion of cracks significantly deteriorate the mechanical properties of the workpiece. These tiny surface cracks, whose width can be as small...
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IPC IPC(8): G01N29/04G01N29/07G01B17/00
CPCG01B17/00G01N29/041G01N29/07G01N2291/011G01N2291/023
Inventor 宋国荣肖珍秦登千吕炎卢东邢智翔何存富吴斌
Owner BEIJING UNIV OF TECH