新型复合材料集装箱地板的分层特性研究

发布时间：2018-02-15 14:37

本文关键词： 集装箱地板三点弯试验分层失效用户子程序　出处：《华南理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：传统集装箱地板是19层的胶合板,由热带阔叶树木制作而成。然而随着硬木资源的逐年锐减以及地板生产工艺的落后,集装箱地板产业的发展已经受到严重的制约,因此对集装箱地板可替代材料以及结构优化的研究迫在眉睫。以承载件弯曲变形时正应力的分布规律为依据,选择了三明治夹芯轻质结构替代胶合板作为集装箱地板的结构;其次从综合性能和制作成本两方面来考虑,提出了以玻璃纤维增强环氧树脂基复合材料为面板,abs塑料为芯层的夹层结构复合板。根据玻璃纤维和环氧树脂固化剂的弹性常数,利用串联和并联模型预测得到单向纤维板的工程弹性常数。以复合材料分层失效准则为评价依据,对新型集装箱地板进行了基于正交试验设计的数值模拟,得到4组最优水平组合的方案。由集装箱地板的使用要求和常见的破坏模式确定刚度约束和粘接强度两个约束条件,选取面层的厚度和芯层的密度作为夹层结构板的设计变量,以夹层结构板的比抗弯刚度作为目标函数,编写优化程序以得到4组方案的最佳工艺参数。采取排水法测出了环氧树脂固化剂和玻璃纤维的密度值,并对不同配比的树脂基体进行了压缩试验,以确定最佳的试验配比。根据4组不同纤维角度和体积含量的方案,对新型夹层结构地板的三点弯试验进行了仿真模拟,仿真结果表明,4组新型夹层结构试验板均能满足设计要求。制备相应的夹层结构板,并进行试验样板的三点弯试验验证仿真结果的正确性。建立纤维增强复合材料单参数的塑性模型,并利用向后返回的欧拉方法改进材料的应力更新算法。基于该算法利用FORTRAN语言编写了用户单元子程序UEL,并在有限元软件ABAQUS上通过了编译,接着测试了该子程序在单轴压缩和反复加载两种不同工况下的力学性能,计算结果与其他文献的试验结果相一致,说明开发出来的子程序精度符合实际工程的要求。最后将塑性子单元应用在单向纤维增强复合材料板面内受载的模拟中,使得模拟结果更加准确。
[Abstract]:The traditional container floor is a 19-story plywood made from tropical broadleaved wood. However, with the decrease of hardwood resources year by year and the backwardness of flooring production technology, the development of container flooring industry has been seriously restricted. Therefore, it is urgent to study the substitute material and structure optimization of container flooring. Based on the normal stress distribution law of load-carrying parts during bending deformation, the sandwich sandwich sandwich light weight structure is chosen as the structure of container floor instead of plywood. Secondly, considering the comprehensive properties and the production cost, a sandwich structure composite plate with glass fiber reinforced epoxy resin matrix composite as the core layer was proposed. According to the elastic constants of glass fiber and epoxy resin curing agent, The engineering elastic constants of unidirectional fiberboard were predicted by using series and parallel models. Based on the delamination failure criterion of composite material, the numerical simulation of the new container floor was carried out based on orthogonal test design. Four groups of optimal horizontal combination schemes are obtained. The stiffness constraint and bonding strength are determined by the use requirements of container floor and common failure modes. The thickness of the surface layer and the density of the core layer are selected as the design variables of the sandwich structure plate, and the thickness of the surface layer and the density of the core layer are selected as the design variables of the sandwich structure plate. Taking the specific bending stiffness of sandwich structure plate as the objective function, an optimization program was compiled to obtain the best technological parameters of the four groups of schemes. The density values of epoxy resin curing agent and glass fiber were measured by drainage method. The compression test of resin matrix with different ratio was carried out to determine the optimum ratio. According to the four groups of different fiber angle and volume content, the three-point bending test of the new sandwich structure floor was simulated. The simulation results show that all of the four new sandwich structure test boards can meet the design requirements. The three-point bending test of the test sample was carried out to verify the correctness of the simulation results. A single parameter plastic model of fiber reinforced composites was established. The stress updating algorithm of materials is improved by backward Euler method. Based on this algorithm, the user unit subprogram UELL is written in FORTRAN language, and the program is compiled on the finite element software ABAQUS. Then the mechanical properties of the subroutine under two different conditions of uniaxial compression and repeated loading are tested. The calculated results are in agreement with the experimental results in other literatures. Finally, the plastic subelement is applied to the in-plane loading simulation of unidirectional fiber reinforced composite plate, which makes the simulation results more accurate.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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