导波在层状结构中的传播分析

发布时间：2018-02-25 15:59

本文关键词： 层状结构导波频散特性板圆柱管无损检测　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科技的进步,复合材料的类别及构成方式也变得越来越多样化。层状结构材料能够由每层具有不同性质的材料叠加而成,获得特殊性能,满足不同工况下对材料的需求。同时其能由使用者自行设计,导致其适用范围愈加广泛。由于其广泛的使用性,对其在役期间材料结构的检测和诊断显得尤为重要,并且已成为现在学者们研究的重点。超声导波检测作为无损检测方法中的一个分支,具有衰减小、传播距离远等优点,已经成为国际无损检测领域一个新兴和前沿的研究领域。我国对该方面的研究由于起步较晚导致落后于世界先进发达国家,不仅表现在理论研究方面而且还表现在仪器制备方面。而本文在前人研究的基础上,利用不同的方法对层状板和层状管中的传播特性进行了研究,主要的研究内容如下:1)对导波在层状板结构中的频散方程用带状单元法进行了求解,并通过数值算例分析了铺层角的变化对板中传播频散特性的影响。接着又针对层状板中含有单层纤维断裂及多层纤维断裂的频散特性进行了研究,分析了不同断层情况下对其传播特性的影响。2)在力学三大方程的基础上,通过引入势函数,利用贝塞尔级数求得了单层各向同性圆柱管中的频散方程。基于此方程,采用传递矩阵法求得了多层层状各向同性管中的方程。最后利用数值算例验证了该方法的正确性,并对单层管和单层板,单层管和多层管中的频散特性进行了对比分析。3)通过状态空间法研究了导波在各向异性层状管中的传播特性,并求得其频散方程。数值算例部分,通过对不同材料频散特性的研究,将结果与参考文献结果对比,验证该方法的正确性。最后又研究了不同倍数下纤维增强对复合材料频散特性的影响,同时又将贝塞尔级数法与状态空间法进行了对比。4)在第三章的基础上,利用阵型叠加法对圆管中的响应问题进行了理论推导。本文采用不同的方法对层状管和层状板中的传播特性进行了研究,并通过数值算例分析了不同情形下的频散特性。通过这些理论研究,期望能给无损探伤技术提供理论参考。
[Abstract]:With the development of science and technology, the types and composition of composite materials have become more and more diversified. Laminated structural materials can be superimposed from different properties of each layer to obtain special properties. At the same time, it can be designed by the users themselves, which leads to a wider range of applications. Because of its wide use, it is particularly important to detect and diagnose the material structure during the period of service. As a branch of nondestructive testing methods, ultrasonic guided wave detection has the advantages of low attenuation and long propagation distance. It has become a new and advanced research field in the field of international nondestructive testing (NDT). Due to its late start, China lags behind the advanced developed countries in the world. In this paper, the propagation characteristics of laminated plates and tubes are studied by using different methods based on the previous studies, not only in theoretical research but also in the preparation of instruments. The main research contents are as follows: (1) the dispersion equations of guided waves in laminated plate structures are solved by the banded element method. Numerical examples are given to analyze the influence of the angle of the layer on the dispersion characteristics of the plate. Then, the dispersion characteristics of the laminated plate containing single layer fiber fracture and multilayer fiber fracture are studied. In this paper, the influence of different faults on its propagation characteristics is analyzed. On the basis of three equations of mechanics, by introducing potential function, the dispersion equation in a single-layer isotropic cylindrical tube is obtained by using Bessel series. The transfer matrix method is used to obtain the equations in multilayer isotropic tubes. Finally, numerical examples are used to verify the correctness of the method, and for single-layer tubes and monolayer plates, The dispersion characteristics of single-layer tube and multilayer tube are compared and analyzed. 3) the propagation characteristics of guided wave in anisotropic layered tube are studied by state space method, and the dispersion equation is obtained. A numerical example is given. Through the study of dispersion characteristics of different materials, the results are compared with the results of reference to verify the correctness of the method. Finally, the influence of fiber reinforcement on the dispersion characteristics of composites is studied. At the same time, the Bessel series method and the state space method are compared. 4) on the basis of the third chapter, The response problem in a circular tube is derived theoretically by using the method of matrix superposition. In this paper, the propagation characteristics of laminated tubes and laminated plates are studied by different methods. Numerical examples are used to analyze the dispersion characteristics in different cases. Through these theoretical studies, it is expected to provide a theoretical reference for nondestructive flaw detection technology.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33

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