局部加强碳纤维复合材料层合板优化方法研究

发布时间：2018-04-13 08:18

本文选题：复合材料 + 单目标优化　；参考：《中北大学》2015年硕士论文

【摘要】：碳纤维复合材料以其较高的比刚度比强度等优越的机械性能,而被广泛应用于航空航天、船舶及汽车等领域。在长纤维碳纤维复合材料的应用中很大一部分为板类零件。由于板类零件的抗屈曲性能以及沿厚度方向上承受载荷能力的不足,需要对其作局部加强。常用的局部加强方法有布置加强筋以及在局部区域增加铺层层数(即改变局部层合板的厚度)两种方法。目前在对加强筋的布置优化中都是基于各加强筋的截面形状及铺层方案均相同的前提下进行的,这些优化不能充分发挥加强筋的作用。因此本文对加强筋截面形状及铺层方案不同时带加强筋层合板的单目标及多目标优化方法进行了研究。在层合板变厚度优化中,许多文献引入了拓扑优化方法。但是由于碳纤维复合材料自身的特点,诸多优化结果的可制造型差。为此很多学者对可制造性碳纤维复合材料的拓扑优化进行了研究。但是优化厚度插值模型的缺陷,优化中引入了大量的设计约束,使得算法收敛速度较慢且优化的结果不是很理想。因此本文对碳纤维复合材料的变厚度优化中提出了新的厚度参数化方法。首先,在带加强筋复合材料层合板的单目标优化中引入了分级优化方法。采用实验设计方法对优化变量及优化过程进行分级。同时为了提高的优化的效率,引入了代理模型方法。其次,采用NSGA-II算法对带加强筋复合材料层合板进行多目标优化。为了使算法适用于可变铺层层数的优化,对算法的算子进行了改造,并引入了Permutation操作。与此同时,本文对铺层层数可变时代理模型的创建方法进行了研究,并应用于优化中以提高优化的效率。再次,在碳纤维复合材料层合板的变厚度优化中,提出了密度分布曲线法来对厚度进行参数化。在此基础上基于BCP方法对变厚度复合材料层合板结构进行了拓扑优化。
[Abstract]:Carbon fiber composites (CFRP) have been widely used in aeronautics and astronautics, ships and automobiles because of their superior mechanical properties such as high specific stiffness ratio and strength.In the application of long fiber carbon fiber composites, a large part of the board parts.Due to the lack of buckling resistance and the ability to withstand load along the thickness of plate parts, it is necessary to strengthen them locally.The commonly used methods of local strengthening are to arrange stiffeners and to increase the number of layers in the local area (that is, to change the thickness of local laminated plates).At present, the optimization of reinforcement reinforcement is based on the same cross-section shape and layer-plan of each reinforcement, and these optimization can not fully play the role of reinforcement.In this paper, the single objective and multi-objective optimization methods for stiffened stiffened laminated plates with different reinforcement are studied in this paper.In the variable thickness optimization of laminated plates, many literatures have introduced the topology optimization method.However, due to the characteristics of carbon fiber composites, many optimized results of manufacturing poor.For this reason, many scholars have studied the topology optimization of manufacturable carbon fiber composites.However, due to the defects of the optimal thickness interpolation model, a large number of design constraints are introduced in the optimization, which makes the convergence speed of the algorithm slow and the result of optimization is not very good.In this paper, a new thickness parameterization method is proposed for the variable thickness optimization of carbon fiber composites.Firstly, the hierarchical optimization method is introduced in the single objective optimization of reinforced composite laminates.The optimization variables and the optimization process are classified by the experimental design method.In order to improve the efficiency of optimization, the agent model method is introduced.Secondly, the NSGA-II algorithm is used to optimize the composite laminated plates with reinforcement bars.In order to make the algorithm suitable for the optimization of variable layering, the operator of the algorithm is modified and the Permutation operation is introduced.At the same time, the method of creating agent model with variable layering layers is studied in this paper, and it is applied to the optimization to improve the efficiency of optimization.Thirdly, the density distribution curve method is proposed to parameterize the thickness of CFRP laminates.On the basis of this, the topology optimization of composite laminates with variable thickness is carried out based on BCP method.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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