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

A technology for enhancing composite materials, attenuation coefficient, applied in suspension and porous material analysis, permeability/surface area analysis, measurement devices, etc., can solve problems such as differences and gaps

A technology for enhancing composite materials, attenuation coefficient, applied in suspension and porous material analysis, permeability/surface area analysis, measurement devices, etc., can solve problems such as differences and gaps

CN104897550AInactive Publication Date: 2015-09-09DALIAN UNIV OF TECH
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  • Method for confirming relation between porosity of CFRP (carbon fiber reinforced plastics) and ultrasonic attenuation coefficient
  • Method for confirming relation between porosity of CFRP (carbon fiber reinforced plastics) and ultrasonic attenuation coefficient
  • Method for confirming relation between porosity of CFRP (carbon fiber reinforced plastics) and ultrasonic attenuation coefficient

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Embodiment Construction

[0023] The present invention confirms the multi-value corresponding relationship between CFRP porosity and ultrasonic attenuation coefficient based on the real shape pore model. The results are as follows: figure 1 shown. The specific steps to obtain the corresponding relationship are as follows:

[0024] (a) Measurement of ultrasonic attenuation coefficient

[0025] Ultrasonic C-scan detection method is used, water is used as the coupling agent, and the α value of CFRP laminates is measured by the bottom plate reflection echo method (such as figure 2 ). Where the thickness of the sample is d, and the reflected sound pressure on the upper surface of the sample is p 1 , the sound pressure of the sample back-wall echo is p 2 , the echo sound pressure on the upper surface of the steel plate is p 3 , the sound pressure reflection coefficient at the interface between water and steel plate is R 13 . The experimental value of the ultrasonic attenuation coefficient α of the CF...

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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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Application Information

Patent Timeline
09 Sep 2015
Publication
CN104897550A
IPC
G01N15/08
Inventors
林莉; 丁珊珊