基于疲劳损伤理论的复合材料胶接修补结构参数研究

发布时间：2018-01-19 04:12

本文关键词： 碳纤维复合材料三维渐进疲劳损伤模型补片参数疲劳损伤疲劳剩余强度　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：碳纤维复合材料因其优越的性能普遍应用于航空航天领域中。复合材料层合板结构或多或少会出现一些微小损伤,鉴于此种情况,复合材料贴片修补逐渐成为人们的一个分析重点。而航空器结构在飞行情况下不仅承受静载荷还受到一些疲劳载荷的影响,因此疲劳载荷下胶接修补结构的剩余强度研究则具有重要的实际意义。本文主要研究了疲劳载荷下复合材料胶接修补结构的损伤扩展和剩余强度。首先,采用APDL编程语言进行碳纤维复合材料建模,并建立复合材料胶接修补结构的疲劳逐渐损伤仿真模型。基于三维Hashin疲劳失效准则,分别考虑了基体开裂疲劳失效、基体压缩疲劳失效、基体纤维剪切疲劳失效、层间拉伸疲劳失效、层间压缩疲劳失效、纤维断裂疲劳失效和纤维压缩疲劳失效七种单元失效模式,使用Shokrieh提出的复合材料衰减模型仿真复合材料单元的疲劳失效扩展情况,并选择突降准则作为疲劳损伤单元材料属性的变化准则。其次,采用以连续介质损伤力学为基础的胶层失效判定准则,使用该胶层失效准则来模拟胶层失效,通过与试验进行对比,保证模型的准确性。最后,建立以疲劳逐渐累积损伤方法为基础的胶接修补结构疲劳损伤模型,研究了补片大小变化时胶接修补结构的疲劳损伤和剩余强度情况。同时,研究补片形状、补片厚度和胶层厚度对胶接修补结构疲劳损伤和疲劳剩余强度的影响,并进行疲劳试验验证仿真计算的准确性,确定疲劳载荷下修补效果最优的补片参数和胶层参数。
[Abstract]:Carbon fiber composites (CFRP) are widely used in the aerospace field because of their superior properties. Laminated composite structures will more or less appear some minor damage, in view of this situation. Composite patch repair has gradually become an important point of analysis, and the aircraft structure is affected not only by static load but also by some fatigue load in flight. Therefore, it is of great practical significance to study the residual strength of adhesive repair structure under fatigue load. In this paper, the damage propagation and residual strength of composite adhesive repair structure under fatigue load are mainly studied. First of all. The modeling of carbon fiber composites is carried out by using APDL programming language, and the fatigue progressive damage simulation model of composite adhesive repair structure is established. The fatigue failure criterion of 3D Hashin is based on the model. The cracking fatigue failure, the compressive fatigue failure, the shearing fatigue failure, the tensile fatigue failure and the compression fatigue failure are considered respectively. There are seven failure modes of fiber fracture fatigue failure and fiber compression fatigue failure. The fatigue failure propagation of composite elements is simulated by using the composite attenuation model proposed by Shokrieh. The sudden drop criterion is chosen as the change criterion of material properties of fatigue damage unit. Secondly, the failure criterion of rubber layer based on continuum damage mechanics is used to simulate the failure of rubber layer. Finally, the fatigue damage model based on the fatigue cumulative damage method is established to repair the fatigue damage of the structure. The effects of patch shape, patch thickness and adhesive thickness on fatigue damage and residual strength of adhesive repair structure were studied. Fatigue tests were carried out to verify the accuracy of the simulation calculation and to determine the optimal patch parameters and rubber layer parameters for the repair effect under fatigue load.
【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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