Dissertation > Industrial Technology > Machinery and Instrument Industry > Instruments, meters > Material testing machine and test equipment > Nondestructive flaw detector

Microwave Nondestructive Testing anechoic tiles affixed quality

Author BaoWuYun
Tutor AnTongYi
School East China Normal University
Course Radio Physics
Keywords Stealth submarines Anechoic tiles Microwave Nondestructive Testing Pyramidal horn High-order mode resonant cavity Genetic Algorithms Optimization Combination of the reflection coefficient modulus greater than 1
Type PhD thesis
Year 2002
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The world Navy To ensure the deterrent and combat force of the sea, in addition to the development of surface ships, the focus is the development of next-generation stealth submarines underwater weaponry. Can be expected in the 21st century, has good mobility, resistance a wave and endurance, and offensive and defensive force strong stealth submarines, will become the main force of the sea battle, it marked the era of stealth combat at sea. Anechoic tiles is the primary means of submarine acoustic stealth, is one of the main challenges facing the production stealth submarines anechoic tile laying. If anechoic tiles laying defects (lack of glue, air gap, bubbles), will reduce performance muffler reduce anechoic tiles pasted firmly, causing the boat wall corrosion and anechoic tiles fall off, affecting the submarine sailing performance and submarine stealth performance . Therefore, accurate check of the only means of anechoic tile laying defects early detection of defects and take remedial measures. Engineering inspection paste anechoic tiles quality needs, our group has developed into engineering CPY-1 microwave nondestructive testing instrument in 1997, reached the international advanced level. The first time a full boat anechoic tiles for real-time scanning detection, detection accuracy rate can reach 90% at the production site. Important issues and some of the strangest phenomena encountered in the development of this article around CPY-1 instrument standing question. The national defense tasks, the authors involved in the development of improved microwave nondestructive testing instrument CPY-1G, engineering detection work, the instrument encountered the work of sensitive points of the research group problem and found for the first time the author reflection coefficient greater than 1 singular phenomenon for explore a number of theories. The main work of this paper are: one, as the main participants completed the development of nondestructive testing instrument the CPY-1G-type microwave debugging process used by the site to provide a more secure, accurate, reliable testing instruments for field testing. First proposed the concept of a \sensitive, much more because: the probe resonant probe, equivalent to the difference between anechoic tile samples using waveguide or coaxial probe the pyramidal cavity perturbation;, anechoic tile samples equivalent to the difference transmission line terminal load change. Thus, exposing the mysteries of the near-field probe of pyramidal horn Abstract sensitive point-namely pyramidal horn probe to constitute a high-order mode resonant probe. The work sensitive point made answers. Third, the use of genetic algorithms to optimize the parameters of the reference sample of the anechoic tiles, elect a suitable reference samples, and check the validity of the results of the genetic algorithm optimization using the analytical method. IG optimization for the production of improved microwave nondestructive testing instrument CPY reference sample basis, to the CPY an IG detect the correct rate of up to 95%. Fourth, first proposed a combination of passive medium, the reflection coefficient can be greater than 1. Under certain conditions, even in a passive medium, the electromagnetic waves in a lossy medium and the lossless medium handover surface, combinations thereof, the reflection coefficient may be greater than l. In this regard, this paper presents a rigorous theoretical analysis. Five proved that the reflection coefficient of the lossy transmission line can also be greater than 1. Lossy transmission line reflection coefficient greater than 1 is given in the paper.

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