Method for confirming relation between porosity of CFRP (carbon fiber reinforced plastics) and ultrasonic attenuation coefficient

Abstract

The invention discloses a method for confirming the relation between the porosity of CFRP (carbon fiber reinforced plastics) and the ultrasonic attenuation coefficient and belongs to the technical field of ultrasonic non-destructive testing. Firstly, by the aid of an ultrasonic C scanning testing method, an area with the relatively uniform primary bottom surface reflection echo amplitude of a CFRP laminated board is selected as a research object, a metallograph of the area is obtained through continuous microtomy, and an in-situ image containing real morphological pores is acquired with a median filter method and the like. A real morphological pore model is further established with a time-domain finite difference method, the multi-value corresponding relation between the porosity P of the CFRP and the ultrasonic attenuation coefficient alpha is obtained through numerical calculation, and support of experimental data is obtained. By the aid of the method, the multi-value corresponding relation between P and alpha is confirmed firstly, and a more effective model basis is provided for deep elaboration of the ultrasonic attenuation mechanism of the complex morphological pores of the CFRP.

Description

technical field [0001] The invention relates to a method for confirming the relationship between the porosity of a carbon fiber reinforced composite material and an ultrasonic attenuation coefficient, which belongs to the technical field of ultrasonic nondestructive testing. Background technique [0002] Carbon Fiber Reinforced Plastics (CFRP) has the advantages of high specific strength, high temperature resistance, and corrosion resistance, and is widely used in aerospace and other fields. Because CFRP will inevitably produce pores during the production process, the existence of pores will directly affect the mechanical properties of the material. The aerospace field usually requires the porosity of composite components to be below 2%, and some main load-bearing components even require porosity below 1%. Therefore, there is an urgent need for an accurate and reliable non-destructive testing method for CFRP porosity in engineering applications. [0003] The principle of u...

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Problems solved by technology

However, there is still a gap between the calculation results of the above model and the experimental results, and the α calculated by different scholars at the same porosity is also different.

In addition, studies in recent years have shown that CFRP pore morphology has an impact on ultrasonic scattering attenuation. Due to the difference in pore morphology, the α value obtained under the same porosity may be different.

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