复合材料波纹梁耐撞性研究

发布时间：2018-04-14 17:23

本文选题：复合材料 + 波纹梁　；参考：《南京航空航天大学》2015年硕士论文

【摘要】：复合材料吸能元件是直升飞机缓冲吸能系统的重要组成部分,在直升机坠毁过程中发挥着保护成员生命安全的作用。因此选择更加合理的复合材料吸能元件是直升机缓冲吸能系统设计的迫切需求之一。本文首先对波纹梁的稳定性进行研究,分析了设置薄弱环节对诱导复合材料波纹梁在受到冲击时触发渐进稳定压溃破坏的必要性。从理论上定性的分析了诱导角度大小对薄弱环节受力的影响规律,并建立了薄弱环节的有限元模型,对不同诱角值下薄弱环节受冲击的峰值载荷进行研究。结果表明薄弱环节的设置对于整个波纹梁的稳定压溃有着重要的影响,合理的诱角值能够有效降低冲击产生的峰值载荷。结合理论分析和有限元仿真结果,提出了可用于结构分析的薄弱环节等效方案。建立了复合材料波纹梁长单波、短单波与三波结构的有限元整体模型,编写了材料子程序VUMAT来定义材料的属性与破坏准则,对破坏后的复合材料材料进行逐层刚度折减,并且将完全失效的单元进行了删除。在波纹梁腹板中加入cohesive单元来实现复合材料分层失效的破坏模式,更加真实的模拟波纹梁在冲击下的细观破坏模式。有限元仿真结果与试验结果的对比分析验证了模型的合理性与有效性。进行了复合材料波纹梁准静态加载与冲击加载两种方式的试验,通过试验研究了复合材料波纹梁结构的破坏模式。结果表明长单波纹梁结构存在稳定性问题,而三波结构具有有较好的吸能能力。
[Abstract]:Composite energy absorber is an important part of helicopter buffer energy absorption system, which plays an important role in protecting the life and safety of members during helicopter crash.Therefore, the selection of more reasonable composite absorber is one of the urgent needs in the design of helicopter buffer energy absorption system.In this paper, the stability of corrugated beam is studied firstly, and the necessity of setting weak link to induce progressive steady crushing failure of composite corrugated beam under impact is analyzed.The influence of inductive angle on the stress of weak link is analyzed qualitatively theoretically, and the finite element model of weak link is established, and the peak load of weak link under different inductive angle is studied.The results show that the setting of the weak link has an important effect on the stability and collapse of the corrugated beam, and the reasonable inductive value can effectively reduce the peak load produced by the impact.Combined with theoretical analysis and finite element simulation results, a weak link equivalent scheme for structural analysis is proposed.The finite element integral model of composite corrugated beam with long single wave, short single wave and three wave structures is established. The material subprogram VUMAT is written to define the properties and failure criteria of the composite material, and the stiffness of the composite material after failure is reduced layer by layer.And the unit that is completely invalid is deleted.Cohesive element is added to the web of corrugated beam to realize the failure mode of delamination of composite material, and the mesoscopic failure mode of corrugated beam under impact is simulated more realistically.The rationality and validity of the model are verified by comparing the finite element simulation results with the experimental results.The failure modes of composite corrugated beams under quasi-static loading and impact loading were studied.The results show that there is a stability problem in the long single corrugated beam structure, while the three wave structure has better energy absorption ability.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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