铝合金带筋薄壁构件超声辅助旋压成形材料流动行为及工艺控制

Thin-walled shell with inner ribs is the main load-carrying structure for aerospace products such as hypersonic aircraft, which decides the products overall performance. Spinning process is an effective method to realize the integrated manufacturing of shells and inner ribs. However, this process still has defects of insufficient filling and rib fracture. This project proposes a novel process to fabricate the thin-walled shell with inner ribs by introducing ultrasonic energy into spinning process based on the mechanism of material flow promotion by ultrasonic energy. Firstly, a material constitutive model and damage prediction model are established to describe the material flow behavior and damage mechanism under the synergistic effect of cyclic loading and ultrasonic energy. Secondly, a simulation model is further built for the ultrasonic-assisted spinning process. The influence of process parameters on the filling of shells and inner ribs of thin-walled components will be investigated and a control method for forming precision will be proposed. Finally, a series of experiments will be conducted based on ultrasonic-assisted spinning machine and a prototype of aluminum alloy thin-walled shell with inner ribs will be fabricated to demonstrate the feasibility of the novel process. This proposal will be a beneficial exploration for the fabrication of thin-walled shell with inner ribs based on the ultrasonic-assisted spinning process from the aspects of material, process and experiments. Besides, it provides a theoretical basis and technical support for high-precision manufacturing of lightweight components for aeronautics and astronautics application.

带筋薄壁筒形构件是高速飞行器等航天装备的主承力结构，决定着装备的整体性能。旋压成形是实现带筋薄壁筒体整体制造的一种有效方法，但存在充筋不足和筋部断裂等缺陷。本项目将超声能场引入旋压成形工艺，提出带筋薄壁构件超声辅助旋压成形工艺新方法，通过超声能场促进材料流动、增加内筋高度，实现带筋薄壁构件高精度整体制造。建立超声辅助旋压成形中铝合金材料本构关系与损伤预测模型，精确描述材料在循环加载和超声能场协同作用下的流动行为与损伤机制；构建带筋薄壁构件超声辅助旋压成形工艺仿真分析模型，揭示工艺参数对薄壁筒体变形与内筋填充的作用规律，提出铝合金带筋薄壁构件超声辅助旋压成形精度控制方法；开展超声辅助旋压成形工艺原型实验，实现高精度铝合金高筋薄壁构件制造。从材料特性、工艺建模与工艺实验三方面为铝合金带筋薄壁构件超声辅助旋压成形做出重要探索，为我国未来航空航天带筋轻量化构件高精度制造提供理论基础与技术支撑。

围绕高超音速飞行器舱体、运载火箭箭体等航天产品的带筋薄壁构件高精确制造需求，提出超声辅助带筋薄壁构件旋压成形新方法，突破现有制造工艺中充筋不足、筋部断裂和外形精度受限的技术瓶颈。基于热激活模型及Hall-Patch关系建立了超声辅助旋压成形铝合金本构模型，可精确描述材料在塑性变形和超声能场协同作用下的流动行为。利用摩擦系数与粗糙度的相关关系表征了超声振动产生的表面效应对旋压过程摩擦力的影响。基于超声振动辅助拉-压循环加载试验明确了超声振动在旋压成形循环加载下的作用效果。根据声学理论，揭示出超声在薄壁筒形件传递过程中的衰减特性。采用应力张量线性变换方法，建立了基于应力不变量I1-J2-J3的各向异性断裂模型，实现了超声作用下铝合金材料损伤的预测，并探明了带筋构件超声振动辅助旋压成形损伤演化规律。利用ABAQUS/Explicit仿真平台，基于分层设置，建立了考虑超声衰减的带筋薄壁构件超声辅助旋压成形仿真模型，分析带筋构件旋压过程变形区和其影响区材料的变形特点，探明了超声振动参数对带筋构件旋压成形中材料流动的影响规律。明确了超声辅助条件下超声振幅、旋轮下压量以及进给速率等工艺参数对构件成形性能的影响规律，提出基于优化超声能量流入以及工艺参数调控的薄壁铝合金带筋构件超声辅助旋压成形精度控制方法。研制出了基于工具头激振的超声辅助旋压成形工艺原型系统，采用变幅杆与工具头一体化的设计结构对超声辅助旋压工具头进行优化，提高了超声加载的极限范围，制备出了高筋铝合金薄壁构件样件，为航空航天轻量化构件高精度制造提供理论基础与技术支撑。