航空大壁板增量装配连接整体扭翘变形主动抑制方法及其机理研究

Taking the process of incremental assembly and connection of large-scale panels as the research object, the active controlling of the complex stress and strain fields and the dynamic coupling effects in the space and time domain of the process is the key of restraining the overall twist and warp deformation. Based on this key issue, take the controlling and homogenizing the complex stress and strain fields in the process of incremental jointing as the guiding ideology. Considering the whole process from the single points to the overall panel, four new methods of deformation suppression and correcting are proposed, including Applied Local Prestress and Overall Pre-Bending(ALP and OPB) in the same station, Prefabricated Inverse Deformation at the panel(PID), and Putted Forward a Reverse-Rolling(PFRR) method for deformation correcting. With the help of mechanical modeling, numerical calculation, and experiment research, an accurate continuous processing of dynamic physical simulation model for the single-point riveting(clamping, drill, riveting) and incremental jointing process is modeled. Based on these models, study the variation regularity of stress & strain field and the mutual influence around the riveting points in a large number of riveting processes under the proposed deformation suppression and correcting methods. Revealing the mechanism of deformation balancing in incremental joining with prestressing / pre-bending method, and a stepwise reduction mechanism between prefabricated inverse deformation and incremental assembly jointing deformation, and coupling superposition and homogenization between PFRR method resulting stress and stress field. Through the comprehensive study of the deformation suppression methods and the experimental verification using proportional parts, to form a system of integrated aircraft structural parts assembly deformation active suppression and safety correction theory. It can provides general guiding principle for the deformation control of complex aircraft structure assembly and affords scientific basis for the development of deformation controlling process.

航空大壁板增量装配连接过程复杂，对其形成的交变应力、应变场及其空间和时间域的动态耦合效应进行主动控制是抑制壁板整体扭翘变形的核心，围绕此核心问题，以主动诱导增量装配连接过程中形成的复杂交变应力、应变场并使之均衡化以减小变形为指导思想。综合考虑从局部到整体的各个工艺环节，研究提出施加钻铆孔位局部预应力、整体预弯、预置反变形及铆后反向滚压校形等四种变形抑制和校形新方法。借助力学建模、数值计算与实验分析，基于增量装配连接过程动态物理仿真模型，系统研究变形抑制和校正方法下增量连接过程中应力、应变场主动诱导、耦合消减和均衡化变化规律，揭示预应力/预弯曲对增量装配连接变形的诱导和变形消减机理、预制反变形与增量装配连接变形之间的逐步耦合消减机制、双向滚压应力与增量连接应力场之间的耦合叠加及均匀化作用规律。通过综合研究和实验验证，形成一套系统综合的理论体系，并为变形抑制策略和工艺规程制订提供科学量化依据。

现代飞机在向高速、高疲劳寿命、高隐身性的方向发展，相应的对壁板装配提出了非常高的准确度要求，使得装配变形的控制问题成为型号研制的技术瓶颈并凸显出来。. 本项目以主动诱导增量装配连接过程中形成的应力、应变场并使之均衡化以减小变形为指导思想。首先，以壁板局部典型结构（含蒙皮和长桁）为对象，为了引导单个铆钉局部材料流动的均匀化，以连接质量为约束，在探讨几何外形超差、疲劳破坏和损伤等失效机制及工艺补偿策略基础上，以力学建模、工艺分析、数值仿真和实验研究为手段，建立了基于后壁筒理论的壁板典型结构铆接全过程力学模型、数值计算模型，深入开展了弹性预应力下单钉、多钉铆接变形抑制机理研究，构建起了一套针对连接结构局部变形主动抑制的弹性预应力和预弯曲理论方法，发现在钉头一侧压力脚范围内施加向上的弹性预应力（1/6左右的压铆力），可以提高局部材料流动的均匀性，减小变形的累积。其次，以连接变形预测结果为输入，融合壁板理论状态，通过连接过程的仿真计算，揭示了反变形在增量变形抑制中的作用机制，并开展了相关的仿真与实验验证；再次，构建了连接局部残余应力的数值计算模型，通过连接局部残余应力的分析与测试，探讨了残余应力与工艺参数的内在关联关系。围绕壁板多钉连接结构架上状态，以力学建模、仿真计算和实验研究为手段，通过校形参数优选，以残余应力的均匀化引导装配变形均匀化为目标，开展了增量连接变形双向滚压校形仿真研究，发现滚轮直径、滚轮间隙、滚轮材质对应力均匀化具有较大影响。最后，通过以上研究的综合与交叉，在铆接前、铆接中、铆接后三个时间维度上，形成了一套系统综合的增量装配连接变形主动抑制与安全校形理论体系，进一步集成数字化测量，拓展研究了基于智能材料和VR可视化的变形智能调控技术，形成了壁板连接变形快速计算软件系统，经过飞机壁板结构的实验验证，验证了该方法体系在抑制航空大壁板整体扭翘变形上的有效性。