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1、南京航空航天大学博士学位论文复合材料构件数字化制造若干支撑技术研究姓名：陈功申请学位级别：博士专业：航空宇航制造工程指导教师：周来水20070901南京航空航天大学博士学位论文I摘 要复合材料构件以其高比强度高比模量可设计性耐热耐腐蚀耐疲劳隐身性好等独特性能而日益受到各行各业的高度重视并在汽车兵器电子航空航天等领域得到越来越广泛应用复合材料的研究水平和应用程度是一个国家科技发展水平的重要体现尤其在航空工业各种先进的飞机无不与先进的复合材料技术紧密联系在一起为满足日益提高的飞机复合材料构件生产制造的要求迫切需要全面应用数字化技术改造现有的生产制造方式和流程逐步实现复合材料构件设计制造的数字化和一
2、体化本文围绕复合材料构件数字化制造的具体需求研究数字化制造过程中的若干关键支撑技术包括复合材料构件铺层曲面的展开预处理复合材料构件铺层曲面的优化展开复合材料构件模具材料的智能选择以及复合材料构件工装零组件的快速装配等所取得的主要成果如下针对复合材料构件铺叠成型中预浸料的铺层展开需要研究了曲面三角化区域划分剪口等曲面展开预处理技术提出了一种基于离散高斯曲率的曲面区域划分方法可有效实现用于铺层曲面展开的曲面区域划分研究并实现了曲面自适应曲面剪口算法该算法将曲面上高斯曲率大于用户所给阈值的点作为剪口起始点再利用最短路径生成算法生成剪口路径该算法可实现全封闭单边界双边界多边界等类型曲面的自适应剪口根据
3、复合材料构件铺层曲面展开的实际需求本文还提出了一种交互式曲面剪口算法根据用户指定的剪口路径关键点算法可生成符合用户需求的剪口路径为了提高材料的下料效率和利用率简化后续的排样工作进一步提出了一种剪口路径优化算法可有效消除锯齿状的剪口路径实现剪口路径的平直化提出了一种以中心三角片为基三角片的涟漪式曲面展开方法该方法能快速获得曲面的初始展开有效减少累积误差在获得曲面初始展开的基础上提出了一种改进的基于弹簧-质点模型的曲面优化展开算法算法的改进主要体现在以下几个方面自适应时间步长的应用提高了算法的速度和稳定性通过对模型中各质点惩罚力的计算实现了翻转三角片的整体调整算法还综合利用初速度和忽略初速度两种方
4、法所具有的优点使得展开过程中翻转三角片的快速调整迭代的快速收敛等关键问题得到了较为圆满的解决该算法能够快速获得网格数量较大的复杂曲面的优化展开有效消除初始展开及优化过程中出现的翻转三角片提高了复杂铺层曲面的展开质量提出了一种基于网格边的复杂曲面优化展开的新方法该方法以曲面三角网格中各网格边长为优化变量以展开前后网格边长误差最小为优化目标以网格复合材料构件数字化制造若干支撑技术研究II中各内部点均可展为约束条件并采用牛顿法和矩阵分块等方法对该优化问题进行求解构造出与原始曲面网格边长误差最小的可展曲面并对构造出的可展曲面用涟漪式展开方法进行展开从而实现复杂曲面的优化展开该方法具有稳定收敛速度快展开
5、精度高展开操作简单等优点可应用于网格数量较小的复杂铺层曲面的优化展开设计复合材料构件铺叠成型模具时模具材料的选择至关重要在分析研究复合材料构件模具材料选择的知识和经验的基础上本文提出了一种模具材料选择模糊决策方法该方法运用加权多因素模糊模式识别技术同时结合基于规则的推理RBR技术和权重动态调整技术实现了具有一定自适应功能的复合材料构件模具材料的模糊决策针对复合材料构件工装快速装配的要求提出了批装配的概念解决了批装配实现过程中装配特征的定义零件实例化实时预览等关键技术实现了螺栓联接螺钉联接销联接等零组件的快速装配设计大大减轻了设计人员的装配设计工作提高了装配设计的效率在对当前典型工装组件库中的实
6、体模型零组件参数表组件的预览方法组件实例化方法等进行分析研究的基础上提出了组件库建库工具的总体框架并在 CATIA 上开发了该组件建库工具实现了组件的建立查询预览调用以及主要参数的显示等功能关键词关键词复合材料构件数字化制造复杂铺层曲面区域划分剪口优化展开模具材料模糊决策快速装配南京航空航天大学博士学位论文IIIABSTRACTComposite components have many inimitable performances such as high specific strength, high specific stiffness, designable, heat-resist
7、ant, corrosion-resistant, fatigue resistant and good stealthy, so they are being given more and more attention in many fields and being applied more and more widely in many domains including automobile, weapon, electron, aviation, space and so on. To some degree, the research level and application l
8、evel of composite material reflect the science and technology developing level of a country. Especially in aviation industry, almost every advanced aircraft is closely related to sophisticated material technologies. To meet the improving manufacturing requirement of composite components on aircrafts
9、, it is urgent to apply digital technologies and improve the current manufacturing mode and manufacturing process. Digitalization and integration of designing and manufacturing of composite components should be realized gradually. Centring on digital manufacturing of composite components, this thesi
10、s dedicated its research to several support technologies in digital manufacturing of composite components. Support technologies studied in this thesis include pretreatment processing of curved surface flattening, optimal flattening of complex ply surfaces on composite components, intelligent decisio
11、n-making for composite component mold material, rapid assembly designing for parts and components of composite components tools, and so on. The main contents and contributions of the thesis are as follows: Aiming at the demands of ply surface flattening of prepreg in ply forming of composite compone
12、nts, some pretreatment methods of surface flattening such as triangulating, dividing, and cutting are studied. A method of surface dividing based on mesh discrete Gaussian curvatures is given. By the method, effect surface dividing results for ply surface flattening can be obtained. An adaptive meth
13、od of creating cutting path is studied and realized, it takes those points whose Gaussian curvature is larger than the given threshold as start points on cutting paths and the whole cutting paths can be acquired with the shortest path generating algorithm. The adaptive method can accomplish cutting
14、tasks on closed surfaces, one boundary surfaces, two boundaries surfaces, and multi-boundaries surfaces. To meet the requirements of flattening ply surfaces on composite components, an interactive cutting method is also given. By some key path points appointed interactively by users, it can create c
15、utting path according to the users demands. For improving material utilization ratio and cutting efficiency, and simplifying the subsequent packing work, a cutting path optimization algorithm is further brought forward, and it can effectively eliminate the jagged cutting paths and make the cutting p
16、aths straight and smooth. A ripple-style flattening method which uses the center-triangle as the base triangle is presented. By the method, an initial flattening with less cumulative error can be rapidly obtained. Based on the initial flattening results, an improved algorithm for surface optimal flattening based on spring-mass model is put forward. The main improvements of the algorithm are as follows: firstly, adaptive time-step improves the speed and stability of current algorithm; second
