复合材料补片胶接修补结构对导波传播的影响研究

发布时间：2018-07-14 09:53

【摘要】：碳纤维增强树脂基复合材料的优良特性有很多,如较高的比强度、比刚度,良好的热稳定性、抗疲劳性和耐腐蚀性,在航空航天等领域有广泛的应用。碳纤维树脂基复合材料结构在成型以及服役过程中,受到各种因素影响,会产生初始缺陷和损伤,若不及时发现和处理,将严重影响结构系统的整体性能。同时,越来越多的补片结构在各种产品上服役,其也容易发生损伤和在发生损伤之后结构的强度会有较大程度上的降低。本文主要研究含圆孔的复合材料补片修补结构对Lamb波传播的影响。首先:对Lamb波进行了相关理论介绍和分析,求解了铝板的频散方程,同时绘制铝板的频散曲线。对压电效应和逆压电效应的压电方程予以介绍,并分析了不同形状及极化方向的压电陶瓷换能器的振动特性。其次,利用通用有限元软件ANSYS编写APDL代码,建立了包含铝板、层合板补片、胶层和锆钛酸铅压电陶瓷换能器(PZT)的压电和逆压电效应的模型,实现在铝板结构中激励Lamb波和接收Lamb波响应信号,并以试验验证模型的正确性。对复合材料补片正面修补后的金属损伤结构进行了数值模拟研究,研究不同补片尺寸及形状修补2mm孔对Lamb波损伤检测的影响。由圆形、方形、菱形补片的仿真模拟结果显示,不同的形状对A0和S0波形包络的影响差异较大,不同尺寸的菱形补片也对A0和S0波形包络有较大差异。再者,基于图形化编译平台LABVIEW搭建半自动实验平台。实验分析了含有不同直径圆孔的铝板和复合材料板的Lamb波传播,分别得出了圆孔直径对直达模式波形包络的幅值影响。其中,复合材料板表面粘贴的压电换能器距离有120mm和180mm两种激励接收方案。最后,经过对比分析复合材料补片单、双面修补后的含10mm直径圆孔的铝板和复合材料板的Lamb波各模式波包,得出了背面补片修补和正面补片修补两种修补方式对Lamb波各模式波形包络影响的差异,给实际的Lamb波检测补片结构提供依据。
[Abstract]:Carbon fiber reinforced resin matrix composites have many excellent properties, such as high specific strength, specific stiffness, good thermal stability, fatigue resistance and corrosion resistance. The structure of carbon fiber resin matrix composites is affected by various factors in the process of molding and service, which will cause initial defects and damage. If not detected and treated in time, the overall performance of the structure system will be seriously affected. At the same time, more and more patch structures are in service in various products, which are prone to damage and the strength of the structure will be reduced to a large extent after the damage. In this paper, the effect of composite patch repair structure with circular holes on Lamb wave propagation is studied. Firstly, Lamb wave theory is introduced and analyzed, the dispersion equation of aluminum plate is solved, and the dispersion curve of aluminum plate is drawn. The piezoelectric equations of piezoelectric effect and inverse piezoelectric effect are introduced, and the vibration characteristics of piezoelectric ceramic transducers with different shapes and polarization directions are analyzed. Secondly, the APDL code is compiled by using the universal finite element software ANSYS, and the piezoelectric and inverse piezoelectric effects of the PZT including aluminum plate, laminated plate patch, rubber layer and lead zirconate titanate transducer (PZT) are established. Lamb wave and Lamb wave response signal are excited and received in aluminum plate structure, and the correctness of the model is verified by experiments. A numerical simulation of the metal damaged structure after repairing the facade of composite patch was carried out, and the effect of different patch sizes and shapes on the damage detection of Lamb wave was studied. The simulation results of round, square and diamond patch show that the different shapes have different effects on the envelope of A0 and S0 waveforms, and the different sizes of diamond patches also have great differences on the envelope of A0 and S0 waveforms. Furthermore, a semi-automatic experimental platform is built based on LabVIEW. Lamb wave propagation of aluminum plate and composite plate with different diameter circular holes is analyzed experimentally. The influence of circular hole diameter on the amplitude of direct mode wave envelope is obtained respectively. Among them, the distance of piezoelectric transducer pasted on the surface of composite plate has two exciting receiving schemes: 120mm and 180mm. Finally, the Lamb wave packets of the aluminum plate with 10mm diameter circular hole and the composite plate after the single and double surface repair are compared and analyzed. The difference between back patch repair and front patch repair on the envelope of Lamb wave waveforms is obtained, which provides a basis for the actual Lamb wave to detect the patch structure.
【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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