Frequency conversion ultrasonic detection method and device for silicon carbide fiber reinforced composite material

Abstract

The invention discloses a frequency conversion ultrasonic detection method and device for a silicon carbide (SiCf / SiC) fiber reinforced composite material, and the frequency conversion ultrasonic detection method provided by the invention comprises ultrasonic waves with different frequency combinations by utilizing different acoustic propagation behaviors of sound waves with different frequencies in the SiCf / SiC composite material. By means of the characteristics that low-frequency ultrasonic waves are high in penetrability and high-frequency ultrasonic waves are good in detection resolution, variable-frequency ultrasonic detection of the SiCf / SiC composite material can be achieved only through one-time scanning, so that the penetrability of incident sound waves in the SiCf / SiC composite material is remarkably improved, meanwhile, the good detection resolution and defect detection sensitivity are achieved, the surface detection blind area is small, and the detection efficiency is high.

Description

technical field [0001] The invention relates to the field of ultrasonic testing, in particular to a method and device for frequency conversion ultrasonic testing of silicon carbide fiber reinforced composite materials. Background technique [0002] Carbon fiber reinforced (SiC f / SiC) composites have been continuously applied in the aerospace field because of their superior high heat resistance. Therefore, its quality inspection and internal defect characterization, evaluation and non-destructive testing are very important. Microscopically and mesoscopically, SiC f / SiC composites have the physical characteristics of porous materials, and it is difficult to implement non-destructive testing and defect evaluation on them. At present, X-ray, ultrasonic and infrared detection methods are mainly used for detection. The main disadvantage of the X-ray detection method is: the X-ray method is not good for SiC f The internal delamination of / SiC composites is insensitive and us...

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Problems solved by technology

The main disadvantage of the X-ray detection method is: the X-ray method is not good for SiC f / SiC composite internal delamination is not sensitive, usually difficult to effectively detect

As an improvement, another detection method is to use the conventional ultrasonic detection method. Its main disadvantage is that the sound wave attenuation is very severe, making it difficult for the incident sound wave to penetrate the SiC being tested. f / SiC composite material, which in turn makes it undetectable. As an improvement method, it is to reduce the frequency of ultrasonic waves, which will significantly reduce the detection sensitivity and detection resolution, and increase the blind area of ​​the detection surface of the ultrasonic reflection method, which cannot meet the requirements of SiC. f / SiC composite material testing requirements, and using the conventional single-frequency ultrasonic testing method, each time an ultrasonic transducer of a different frequency is replaced, it is necessary to re-scan the test, and the detection efficiency is very low

Another option is to use infrared detection method, but the main disadvantage of infrared detection method is: only for SiC f Large defects on the surface and near the surface of / SiC composite materials have a certain detection ability, but it is difficult to detect quantitative defects, and it is difficult to accurately control the thermal loading process, which may easily lead to misjudgment or missed detection of test results

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