蒙皮层合结构变形分析与设计工艺优化

发布时间：2018-05-10 04:44

本文选题：编织材料 + 层合结构　；参考：《兰州理工大学》2017年硕士论文

【摘要】：纤维编织复合材料是一种新型高温结构复合材料和功能材料,不仅具有极好的生物相容性、高比强度、高比刚度、优异的抗烧蚀性能及高温下良好的力学性能保持度等特点,而且具有抗冲击损伤性能好、抗分层、垂直结构方向强度高、开裂不敏感、损伤扩展慢的优良品质,因而广泛应用于航空航天领域。针对大型异质层合制件在制造过程中通常出现一定变形的问题,利用有限元仿真技术,探索异质层合变形的内在原因,通过结构和工艺等手段实现异质层合材料变形的有效控制,提升大型异质层合复合材料方向的工程技术水平。本研究在分析所用纤维编织复合材料微观组织结构特点的基础上,从材料研究新视角出发,以纤维增强树脂基复合材料微观组织结为研究对象,在碳纤维大小的尺度上,依据纤维编织结构和树脂基体各自的性质、各自的几何状态与取向状态来预测及设计纤维编织材料的性能与行为,确立了以“数字化、数值化、虚拟化、可视化”和“虚拟材料”技术手段为前提的“材料模型”建模思想,采用三维商用建模软件CATIA完成了某飞机蒙皮CKFR-PMCs编织型层合结构几何模型的建立。在有限元分析阶段,首先对大型整体异质层合制件做模流分析,旨在研究制件注射过程中出现变形情况,再设计一种使得注件在注塑过程中不会产生翘曲变形的虚拟材料和虚拟工艺,比较两次注射过程各物理量随时间的演变。模流分析真实地再现了注射过程中塑料熔体(流变体)在模具型腔内的流动;准确地预测了制件“注射-压缩保持-冷却”工艺流程中各个阶段温度、压力等随时间的演变。再对注塑过程状态数值化,进一步将数值化的状态传输到有限元分析软件ABAQUS中进行工艺分析,再现注射成型整个过程中制件表面温度与应力变化,研究工艺参数对制件变形的影响,达到优化工艺的目的,得到了异质层合复合材料在温度载荷作用下的应力场、应变场以及位移场的分布,实现了不同有限元分析软件之间数据的交换和状态的继承,建立了“注射压缩模塑成型仿真平台”,在此仿真平台上可以完成“模具预热-注射成型-压缩成型-冷却固化”这一完整的工艺流程中各个环节技术指标参数与工艺参数的计算性优化,对大尺寸、跨尺度的多元多相异质复合材料的成型工艺及变形预测具有一定的指导作用。
[Abstract]:Fiber braided composite is a new type of high temperature structure composite and functional material. It not only has excellent biocompatibility, high specific strength, high specific stiffness, excellent ablation resistance and good mechanical performance retention at high temperature, etc. It is widely used in aeronautics and astronautics because of its good impact damage resistance, good delamination resistance, high vertical structural strength, insensitive cracking and slow damage expansion. In view of the problem of deformation in the manufacturing process of large heterogeneous laminates, the internal causes of the deformation of heterogeneous laminates are explored by using finite element simulation technology. By means of structure and technology, the deformation of heterogeneous laminates can be controlled effectively, and the engineering technology level in the direction of large heterogeneous laminated composites can be improved. Based on the analysis of the microstructure characteristics of the fiber braided composites, the microstructure of fiber reinforced resin matrix composites was studied from a new perspective of material research, and on the scale of carbon fiber size, According to the properties of fiber braiding structure and resin matrix and their geometric and orientation states, the properties and behaviors of fiber braiding materials are predicted and designed. Based on the idea of "material model" modeling based on visualization "and" virtual material "technology, the geometric model of a aircraft's CKFR-PMCs braided laminated structure is established by using the three-dimensional commercial modeling software CATIA. In the stage of finite element analysis, first of all, the mold flow analysis is done for the large integral heterogeneous laminated parts, in order to study the deformation in the injection process. A virtual material and a virtual process are designed to prevent the injection from warping in the injection molding process. The physical quantities of the two injection processes are compared with each other over time. The flow of plastic melt (rheological body) in the mold cavity during injection process is reproduced by mold flow analysis, and the evolution of temperature and pressure with time in each stage of the injection, compression, retention and cooling process is accurately predicted. Then the state of the injection molding process is digitized, and the numerical state is further transferred to the finite element analysis software ABAQUS for process analysis, and the change of surface temperature and stress during the whole process of injection molding is reproduced. The effect of process parameters on the deformation of the workpiece is studied, and the distribution of stress field, strain field and displacement field of heterogeneous laminated composites under temperature load is obtained. The data exchange and state inheritance between different finite element analysis software are realized, and the simulation platform of injection compression molding is established. On this simulation platform, the computational optimization of the technical parameters and process parameters of each link in the complete process of "Mould preheating, injection Molding, Compression Molding and cooling curing" can be completed. The forming process and deformation prediction of multi-phase heterogeneous composite materials with cross-scale are instructive.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332

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