Research On Non-destructive Testing Technology For Aerospace Composite Materials

With the development of spaceflight technology and the application of advanced composite materials in aerospace field,as well as the structural and performance characteristics of composite materials,the corresponding nondestructive testing technology is facing new challenges.Non-destructive testing is the method that use advanced theory and technology on the surface and internal defects of the shape,location,size of the material according to sound,heat,vibration and other characteristics of the measured material under the premise of not undermine the appearance and internal structure of the object.This thesis briefly introduces the characteristics of composite materials and the types of common defects,summarizes the main methods of nondestructive testing of aerospace composite materials,analyzes the advantages and disadvantages of the non-destructive testing methods,then designed and built the Percussion Detection System for Aerospace Composites based on Lab VIEW.The main contents of this thesis are summarized as follows:The experiment verifies the relationship between the vibration characteristics of the composite surface and the degree of defect,designed percussion of the probe,the driver module and the signal acquisition module,It can convert analog signals acquired by sensors into digital signals and sent to the upper computer for processing.Designed and built a set of Kinetic Control System which can adapt to various working environment,has high degree of automation and precise detection.Programmed the program of upper computer based on LabVIEW,the multichannel or single channel percussion detection of the tested material can be performed by the host computer program,and the test results are displayed in the form of intensity graph.The results of percussion test show that single-channel detection can detect the edge of defect accurately,and it is convenient to determine the position of defect and the severity of defect.But single-channel detection takes a long time and the detection efficiency is low.If there is no high demand for defected object,only need to determine the defect location,the use of multi-channel detection can improve the detection efficiency;there is a high demand for defected object,need to find the exact location and contour defects,it should be used for single-channel detection.The actual detection process could use multi-channel detection combine with single-channel detection to improve the detection efficiency.