The Research Of Terahertz Nondestructive Testing For Internal Inclusions And Defects

Composite materials have some characters like high mechanical strength and low-weight,have made the composite materials can be applied to many applications where historically more traditional materials like metals,plastics or ceramics have been used,so quality of composite materials are becoming strict requirements.Nondestructive testing is the guarantee for the performance of composite materials,terahertz nondestructive testing has obvious advantages.In this paper,for the existence of inclusions and defects within the composite materials,combined with the actual test experience and engineering applications,start from the principle of terahertz technology,nondestructive testing and frequency modulation continuous wave,nondestructive testing of the inclusions or defects in homemade and actual samples by SynViewScan 300 continuous terahertz imaging system.The main core work as follows:(1)The design and production of samples.Design sample test the depth resolution of continuous terahertz imaging system.Design bonded structure sample that contain different inclusions or defects to test the detection effect for different samples and different defects;(2)Results analysis of homemake sample.Analyzing the results of the homemake samples systematically,compare the two-dimensional terahertz hierarchical maps and the depth information curve.Describing the depth resolution of the continuous terahertz imaging system and detection effect of the bonded structure sample;(3)Results analysis of the actual samples.Through the detection of five kinds of internal inclusions or defects in the actual samples,the detection performance of SynViewScan 300 for unknown defects in the actual sample is described.The results show that the depth resolution of SynViewScan 300 can reach 1mm.The system has good detection ability for different defects in the bonding structure,and the defects in the actual sample also can be detected.The research provides an effective method for the detection of internal defects in composite samples.