多角度异源层合板屈曲状态下的应力集中

发布时间：2018-03-31 08:41

本文选题：复数域　切入点：耦合场　出处：《兰州理工大学》2016年硕士论文

【摘要】：基于纤维增强层板正交各向异性特性,在许多实际工程的内核及其外延,应力集中现象依然为宏观影响因素,成为理论研究题材的源。本文采用复数域和有限元法分析揭示了椭圆存在与应力分布的相关性,具体表现为类逆解法下的应力场决定铺层方式以及温度、湿度耦合场层合板物理方程表征。全文对复合材料层合板屈曲问题和孔口应力集中问题施以严密的理论推导,主要表现在如下几个方面:(1)假设层合板在受均布力和剪切效应共同作用下发生屈曲由于层合板与梁杆尺寸的差异性和层合板铺层排布的非单向性,板处于拉伸或压缩状态下,变形的不一致性导致层合板原有的面内平衡被打破,继而逐渐向板面法线方向屈曲并建立新的稳定平衡。(2)假设层合板孔口问题影响其稳定性孔口位置、孔口尺寸和孔口类型影响板内应力分布,进而板屈曲时产生过屈曲不可逆塑性变形或者层合板全域进行挠度再分布。(3)设定层合板的变形仍遵循小变形。层合板同时受均布力和剪切效应共同作用,如果共同作用产生的挠度与各自产生的挠度叠加等效,孔口应力集中问题因而视为不同受力状态的合效应。通过严密的理论论证和与既有的理论研究成果和实验数据参照,主要研究工作如下:(1)给出多角度异源层合板多重受力状态下屈曲性能的研究途径针对多角度异源层合板严重的各向异性,拟采用屈曲满足叠加原理假设,并推证假设的合理性。(2)给出层合板孔口应力集中问题的研究方法利用复变函数法和有限元方法实现孔口应力极值的理论计算,并探讨孔口应力分布的影响因素。(3)提出层合板稳定性临界值与孔口的相关性研究孔口位置、孔口大小和孔口类型对临界值的程度相关性,分析并给出临界值与各影响因素间的量化关系。(4)设想多角度异源层合板屈曲性能研究的其它途径
[Abstract]:Based on the orthotropic properties of fiber reinforced laminates, stress concentration is still a macroscopical factor in the core and extension of many practical projects, which has become the source of theoretical research.In this paper, the correlation between the existence of ellipse and the stress distribution is revealed by using complex domain and finite element method. It is shown that the stress field determines the layering mode and the physical equation of the coupled field of temperature and humidity.In this paper, the buckling problem of composite laminated plates and the stress concentration problem at the orifice of composite laminates are derived from a rigorous theoretical derivation.The main performance is as follows: (1) assuming that the laminated plate is buckled under the combined action of uniform force and shear effect. Due to the difference of the size between the laminated plate and the beam rod and the non-unidirectional arrangement of the laminated plate, the laminated plate is in the state of tension or compression.The inconsistency of deformation causes the original in-plane equilibrium of the laminated plate to be broken, and then buckles gradually to the normal direction of the plate and establishes a new stable equilibrium. 2) assuming that the orifice problem of the laminated plate affects the location of the stable orifice.The size of the orifice and the type of the orifice affect the stress distribution in the plate, and then the post-buckling irreversible plastic deformation or the deflection redistribution in the whole region of the laminated plate. 3) the deformation of the laminated plate still obeys the small deformation.The laminated plate is subjected to the interaction of uniform force and shear effect at the same time. If the deflection produced by the joint action is equivalent to the deflection produced by each other, the stress concentration at the orifice is regarded as the combined effect of different stress states.The main research work is as follows: (1) A research approach to the buckling behavior of multi-angle heterogenous laminated plates under multiple loads is given. In view of the serious anisotropy of multi-angle heterogeneous laminated plates, the buckling method is proposed to satisfy the superposition principle hypothesis.The research method of stress concentration at the orifice of laminated plate is given. The complex variable function method and the finite element method are used to realize the theoretical calculation of the stress extreme value at the orifice of the laminated plate.The relationship between the critical value of laminated plate stability and the orifice is discussed. The relationship between the location of the orifice, the size of the orifice and the type of the orifice on the critical value is discussed.The quantitative relationship between the critical value and the influencing factors. (4) other ways to study the buckling behavior of multi-angle heterogenous laminates are proposed.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB33

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