芳纶纤维层合板的冲击力学行为

发布时间：2018-06-02 16:19

本文选题：芳纶纤维 + 层合板　；参考：《太原理工大学》2015年硕士论文

【摘要】：纤维增强复合材料层合板和纤维金属层合板（FMLs）因其具有比强度高、比模量高、可设计性强、制备工艺简单以及良好的抗疲劳性等优越的力学性能被广泛用于航空航天、汽车舰船、交通运输和现代保护设备等领域。本文采用冲击加载的方式，分别从实验和数值模拟两个方面对芳纶纤维/环氧树脂（Kevlar/Epoxy）复合材料层合板和芳纶纤维-铝合金层合板（ARALL）的动态响应进行了系统的研究。基于编织Kevlar/Epoxy复合材料层合板的平头弹冲击实验，分析了结构在不同冲量下的变形失效模式及抗冲击性能。实验表明复合板的变形失效模式主要表现为：1.弹性变形；2.复合板表面嵌入失效及整体塑性大变形；3.背面纤维的拉伸断裂及分层失效。基于实验研究，应用LS-DYNA971有限元程序对不同铺层数的复合板在冲击载荷作用下的动态响应过程进行了数值模拟，子弹作用区域边缘处首先发生近似圆形的嵌入失效，而在板背面呈近似正方形的破坏区域，模拟结果与实验吻合较好。计算中重点分析了纤维板铺层数对结构动力响应的影响，，在一定冲量范围内，通过对复合板层数的优化，能够有效地减小后面板挠度，提高结构的能量吸收效率，增强结构的抗冲击性能。通过ARALL的球头弹冲击加载实验，分析了不同冲量下ARALL的变形失效模式。实验表明：1.试件的变形区域划分为未变形区域、整体大变形区域及局部变形/失效区域；2.背面铝层出现了“对角线撕裂”和“十字撕裂”两种撕裂模式；3.相比于冲击面复合材料层，背面复合材料层遭受了更严重的分层损伤和基质破裂。基于实验结果，应用多尺度混合建模的方法，通过HYPERMESH和LS-DYNA971建立了ARALL的有限元模型并进行了数值模拟研究，该模型可以清晰的反映出纤维层和结构整体的变形失效模式：基体的失效、纤维拉伸断裂、层间相对滑移、分层及整体大变形。该方法采用整体建模与纤维尺度建模相结合的方式，在保持较好的计算精度的同时可以有效减少网格数，为大尺寸纤维复合结构的数值模拟计算提供了一种新的建模方法。
[Abstract]:Fiber reinforced composite laminates (FMLs) and fiber metal laminates (FMLs) are widely used in aeronautics and astronautics because of their high specific strength, high specific modulus, high designability, simple preparation process and good fatigue resistance. Car and ship, transportation and modern protection equipment and other areas. In this paper, the dynamic responses of aramid fiber / epoxy resin Kevin / Epoxycomposite laminates and aramid fiber / aluminum alloy laminated laminates are studied by means of impact loading and numerical simulation. Based on the flat-end impact test of braided Kevlar/Epoxy composite laminates, the deformation failure modes and impact resistance of structures under different impulses were analyzed. The experimental results show that the main deformation failure mode of composite plate is 1: 1. Elastic deformation. Surface embed failure and large plastic deformation of composite plate. Tensile fracture and delamination failure of the back surface fiber. Based on the experimental study, the dynamic response process of composite plates with different layers under impact load was simulated by using LS-DYNA971 finite element program. At first, an approximate circular embedding failure occurred at the edge of the bullet action area. The simulation results are in good agreement with the experimental results. In the calculation, the influence of the number of fiberboard layers on the dynamic response of the structure is analyzed. In a certain impulse range, the deflection of the rear panel can be effectively reduced and the energy absorption efficiency of the structure can be improved by optimizing the number of layers of the composite board. Enhance the impact resistance of the structure. The deformation failure modes of ARALL under different impulses are analyzed by means of the impact loading test of the spherical projectile of ARALL. The experiment shows that 1: 1. The deformation area of the specimen is divided into the undeformed region, the whole large deformation area and the local deformation / failure area. "diagonal tear" and "cross tear" appear on the back of the aluminum layer. Compared with the impact surface composite layer, the back composite layer suffered more serious delamination damage and matrix rupture. Based on the experimental results, the finite element model of ARALL is established by means of HYPERMESH and LS-DYNA971, and the numerical simulation is carried out by using the method of multi-scale hybrid modeling. The model can clearly reflect the deformation failure modes of fiber layer and structure: the failure of matrix, the tensile fracture of fiber, the relative slippage between layers, the delamination and the whole deformation. This method combines global modeling with fiber-scale modeling and can effectively reduce the number of meshes while maintaining good computational accuracy. It provides a new modeling method for the numerical simulation of large-sized fiber composite structures.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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