Composite material porosity value evaluation method based on ultrasonic detection

Abstract

The invention belongs to the technical field of composite material and nondestructive detection, and relates to a composite material porosity value evaluation method based on ultrasonic detection. The method is implemented as follows: an ultrasonic transducer, an ultrasonic detection unit, porosity evaluation modeling, porosity database establishment and other main parts. Detection signals of a composite material test block with known porosity content are detected to obtain ultrasonic parameters for establishing a porosity evaluation model, and a porosity database is established according to the species and forming process of a composite material to be detected, wherein the adjacent porosity content difference range of the composite material test block for modeling is 0.5%-1%. By selection of a corresponding species and forming process in the composite material porosity database, porosity ultrasonic value evaluation of different composite materials can be realized, and auto alarm, recording, storing and the like of porosity values can be performed in real time. The composite material porosity value evaluation method can be used in interior and outdoor porosity value evaluation and detection of composite material engineering structures, does not require special sample preparation, and is high in efficiency and free of pollution.

Description

technical field [0001] The invention belongs to the technical field of composite materials and nondestructive testing, and relates to a numerical evaluation method of composite material porosity based on ultrasonic testing. Background technique [0002] With the promotion and application of composite materials in stressed structures, it is necessary to detect and evaluate the porosity of composite materials in the process of composite material structure design and structure manufacturing to prevent the content of porosity from exceeding the safety threshold allowed by the design. At present, in the manufacturing process of composite materials, the porosity sampling method of composite materials is mainly used to indirectly infer the porosity content of actual composite parts: the specific method is: (1) use the sampling and sample preparation of furnace parts , and then carry out metallographic observation to observe whether there are gaps in the section of the sample prepar...

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Problems solved by technology

Due to the strong random distribution of porosity in the composite material manufacturing process, coupled with the strong discreteness of the composite material itself, the most significant shortcoming of these two methods is that they cannot obtain the pores in the actual composite material parts. It is only an assumption based on theoretical process equality and strict uniform process quality, which is far from the actual situation, and requires special sample preparation, long cycle, low efficiency, and environmental pollution. Currently, composite materials, etc. It is difficult to popularize and apply in engineering structure; (3) Use the attenuation change of the bottom wave of the ultrasonic wave in the composite material to judge the porosity of the composite material. Its obvious disadvantage is that there are many factors that affect the change of the amplitude of the bottom wave or transmitted wave, and in many cases, the decrease of the amplitude of the bottom wave or transmitted wave is not necessarily due to the porosity. It is caused by the existence of the probability, which is easy to cause misjudgment. Therefore, this method has not been popularized and applied in practical applications.

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