Dissertation > Industrial Technology > Radio electronics, telecommunications technology > General issues > Basic theory > Microwave and UHF

Research on Microwave Detecting Technology of Composite Material and Liquid Component

Author XingHeMin
Tutor DuanZiHua
School Taiyuan University of Technology
Course Chemical Process Equipment
Keywords defect component composite material mixed liquid nonde-structive testing microwave technology
Type Master's thesis
Year 2013
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Composite material overcomes the disadvantages of a homogeneous material, and plays the advantages of its constituent materials. Composite ma-terial has high specific strength, stiffness ratio, corrosion resistance, fatigue re-sistance and other excellent performance. At present, composite material be-came a new engineering material with great vitality. But there are some inevita-ble defects in the manufacturing process. The quality of composite material is direct influenced by defects, such as crack, hole and layer. So detection of com-posite material was always the focus of every people’s attention and was a po-werful criterion to evaluation of defects of composite material. The common methods of NDT for composite material were ultrasonic testing and radiographic testing. But they have some disadvantages, such as serious attenuation and radi-ation hazard. Therefore interdisciplinary knowledge was used in this paper for internal defects of composite material. The excellent performances of micro-wave detecting technology were better penetration and little radiation hazard.The component of liquid is one of the important monitored parameters of products and intermediates in industrial processes. Among detection methods of component, regular sampling inspection method was common, and more widely applied. But this method has limitations and potential safety problems for long distance transportation and large capacity storage. However Real-time on-line long-term detection method was put forward in this paper. This method en-sures that component of mixed liquid was monitoring on time.According to the microwave transmission characteristics, a new me-thod was put forward in this paper to test internal defects of composite materials and components of mixed liquid. Microwave technology is simple and without coupling agent, especially is little harm to the detecting people. This method could real-time online long-term detection components of mixed liquid, the same for running piping and large capacity storage. To enrich nondestructive testing technology, microwave detection technology plays an increasingly im-portant role, and is a new method to test components of mixed liquid.Mainly content of this paper is theoretical research and experimental research of microwave detection technology. According to the characteristics of microwave transmission and medium, we can know the principle of microwave detection technology. On this basis, microwave detection systems of composite material and mixed liquid were built. The better microwave response signals of defects and components were to be obtained. According to analysis and describe microwave response signals, we can get some reasonable conclusions. They are as follows:(1) The microwave NDT system of composite material can be used for determining the position of composite material internal defects (crack and hole). The better microwave response signal is return loss (RL). When Micro-wave waveguide probe met defects, microwave response signal would mutate in the test frequency. According to comparison with reference sample, defects can be found quickly;(2) According to measuring microwave response signal (RL), width of composite material internal crack and diameter of composite material internal hole can be determined. So size of defects can be estimated;(3)Microwave response signal of composite material internal defects (RL) and non-metallic base materials of composite material are concerned. Dif-ferent non-metallic base have different dielectric constant. Microwave transmis-sion was great influenced by dielectric constant of non-metallic base material. When the value of non-metallic base material dielectric constant increase, abso-lute value of return loss will become higher;(4) The microwave system of mixed liquid can be used for real-time online long-term detection components of mixed liquid. When Microwave wa-veguide probe met mixed liquid, microwave response signal would mutate in the test frequency. So components of mixed liquid can be determined;(5) When increasing microwave signal frequency, the accuracy of detection can be improved. When improving microwave signal frequency, mi-crowave response signal (standing wave ratio) becomes more sensitive;(6) Because of dielectric constant of various components is different, components of mixed liquid can be determined by microwave technology. Pre-cision can be improved by increasing difference between dielectric constant of each component. In this paper, the minimum difference of liquid dielectric con-stant is4.4, and the testing accuracy is10%. The maximum difference of liquid dielectric constant is58.4, and the testing accuracy is5%.This paper shows that microwave detection technology can be used for testing composite material internal defects and mixed liquid components rapidly. Microwave technology plays an important role in rich nondestructive testing technology and detection component of mixed liquid.

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