【作者】 王伟；

【导师】 陈普会；

【作者基本信息】 南京航空航天大学 ， 飞行器设计， 2016， 硕士

【摘要】 复合材料加筋板在航空工程领域应用广泛。然而筋条-蒙皮界面的脆性导致界面处容易产生脱粘失效,这极大地阻碍了复合材料在飞机结构上的应用和发展。针对这一问题,国内学者提出一种界面增韧方法——离位增韧技术。该技术可以大幅度提高界面的韧性,改善复合材料加筋板的界面性能。本文从试验研究的角度,对比研究了离位增韧和未离位增韧复合材料加筋板在三点弯曲静力载荷、三点弯曲疲劳载荷和轴向压缩静力载荷下的长桁-蒙皮界面性能。对于静力试验,利用监测应变的方法分析界面的脱粘起始和损伤扩展,结合载荷-位移曲线分析加筋板的失效过程,研究离位增韧对界面抗剥离性能的影响;对于疲劳试验,实时记录循环载荷次数和相应的分层扩展长度,对比不同界面分层扩展速率的差异,研究离位增韧对界面耐久性能的影响。本文从数值分析的角度,针对静力试验,基于Abaqus软件建立了复合材料加筋板的渐进损伤模型,考虑复合材料层合板和长桁-蒙皮界面的失效,采用合适的失效判据和材料退化方案,有效地模拟了结构的损伤扩展和最终失效。再进一步结合试验研究了结构的失效机理,分析了离位增韧对界面性能的改善效果;针对疲劳试验,结合试验分析和VCCT计算结果,对比研究了两种界面分层扩展速率与能量释放率之间的关系。更多还原

【Abstract】 Composite stiffened panels are widely used in aviation engineering. Debonding and failure often occur at the interface of the stringer and the skin as its poor toughness, which hinders the development of composite in the structure of airplanes. According to this situation,domestic scholars provided a method to toughen the interface—the "ex-situ" toughening technology, which could greatly raise the toughness of the interface and improve the performance of composite structures.In this paper, three-point bending static tests, three-point bending fatigue tests and axial compression static tests were set up towards a series of "ex-situ" and "unex-situ" toughened composite stiffened panels to compare and research the performance of two kinds of interfaces. In static tests, strain gages were used to analyze the initial debonding and damage propagation of the structure. In fatigue tests, the cyclic loading times and the length of delamination were recordedin the real time to analyze the spread rate of delamination of different interfaces.Then towards static tests, a progressive damage FE model of the composite stiffened panel was established via Abaqus to study the mechanisms of interface damage and final failureof the structure.This approach employed Hashin failure criteria andmaterial stiffness degradation, and it was able to predict the damage initiation and evolution. Towards fatigue tests, the test and VCCT results were combined to research the relationship between the spread rate of delamination and the strain energy release rate.更多还原