平纹编织复合材料连接性能分析

发布时间：2018-01-09 19:21

本文关键词：平纹编织复合材料连接性能分析　出处：《南昌大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前编织复合材料层合板以其优良的性能被广泛用于航空航天工程设计中,而连接接头的安全可靠问题已成为复合材料实际结构设计的关键。复合材料连接主要包括:胶接、机械连接以及二者的混合连接。本文主要从试验角度出发,针对平纹编织复合材料层合板胶接中的单搭接接头性能和机械连接中的单钉双剪连接挤压性能进行分析研究。通过试验方法分析了不同胶层厚度对单搭接胶接强度的影响,结果发现试件出现多种破坏模式,且在同种破坏形式下,单搭接胶接强度随着厚度增大而减小。通过观察发现,试件切割凹槽深度的不同是影响破坏模式的主要因素,数值模拟也印证了这点。然后在本试验范围内,讨论了纯剪理论在实际工程应用中的误差。基于单钉双剪挤压试验,探究了不同铺层比例对平纹编织复合材料单钉双剪挤压强度的影响。结果表明:在本试验范围内,试件破坏应力随着0?45铺层所占比例的增加而非线性提高;单钉双剪挤压破坏过程是逐层失效的过程,在试验过程中会出现初始损伤点,且随着0?45铺层所占比例的增加,破坏的逐层失效特征会越来越不明显。通过在ABAQUS中对平纹编织复合材料层合板单钉双剪挤压进行模拟,基于二维Hashin失效准则,对单钉双剪挤压初始失效层及失效位置进行了判定。模拟结果表明在相同挤压位移作用下,越靠近层合板内部的单层越容易首先发生破坏且首先发生失效的位置是孔周0??0处。通过对平纹编织复合材料层合板单钉双剪挤压逐层孔周径向应力分布数值模拟结果分析,假设了孔周逐层失效区域,并将上限理论应用到平纹编织复合材料单钉双剪连接强度计算中去,基于二维Hashin失效准则,探究了一种能有效预测本文所用平纹编织复合材料层合板的单钉双剪挤压强度的方法。
[Abstract]:At present, braided composite laminates are widely used in aerospace engineering design for their excellent properties. The safety and reliability of the connection joint has become the key to the practical structural design of composite materials. The composite joints mainly include: bonding, mechanical connection and the hybrid connection. This paper mainly from the point of view of the test. The properties of single lap joint in plain braided composite laminate bonding and extrusion performance of single nail double shear joint in mechanical connection were studied. The strength of single lap joint with different thickness of adhesive layer was analyzed by experimental method. The effect of degree. The results show that there are many failure modes in the specimen, and under the same failure mode, the strength of single lap bonding decreases with the increase of thickness. The cutting depth of the specimen is the main factor that affects the failure mode, and the numerical simulation also confirms this point. Then in the scope of this test. The error of pure shear theory in practical engineering application is discussed. The effects of different layering ratios on the extrusion strength of plain braided composites with single nail and double shear are investigated. The results show that the failure stress of the specimens increases with 0? The failure process of single nail and double shear extrusion is the process of failure layer by layer, and the initial damage point will appear in the process of test, and with 0? With the increase of the proportion of 45 layers, the failure characteristics of failure layer by layer will be less and less obvious. The single nail double shear extrusion of plain braided composite laminates is simulated in ABAQUS. Based on the two dimensional Hashin failure criterion, the initial failure layer and the failure position of single nail and double shear extrusion are determined. The simulation results show that under the same extrusion displacement. The closer the laminated plate is to the inner layer, the easier it is for the first failure to occur and the first failure is at the hole circumference 0? ? Through the numerical simulation results of radial stress distribution around holes in plain braided composite laminates with single nail and double shear extrusion, the failure zone of each layer of holes is assumed. The upper bound theory is applied to the strength calculation of single nail and double shear joint of plain braided composites based on two-dimensional Hashin failure criterion. An effective method for predicting the extrusion strength of flat braided composite laminates with single nail and double shear is studied.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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