大型构件去除成形中零残余应力控制

李淑慧

摘要：现代航空工业的快速发展，对飞机高速、高机动性能、高负载和服役寿命提出了越来越高的要求，因此需要在不断提高飞机结构强度和效率的前提下降低其自身结构重量。为此，新一代飞机普遍采用毛坯直接铣削加工成具有复杂型腔、筋条和凸台的大型整体结构件，比如整体壁板、后尾梁缘条、隔框等大型复杂结构件，进而对其加工制造质量提出了更加严格的要求。 以加工制造过程中残余应力的传递和控制为主线，针对整体薄壁构件表面质量控制要求，以高速切削已加工表面残余应力的传递作为主线，建立高速切削已加工表面在力、热耦合作用下的残余应力预测模型，并分析已加工表面完整性与构件疲劳裂纹萌生的关联机制，从而有效指导切削加工过程表面残余应力的调整控制。 针对大型整体薄壁构件切削加工形状精度控制要求，研究大型整体薄壁构件高速铣削加工过程中体残余应力的释放和重分布规律，发现厚板毛坯初始体残余应力的非均匀释放和重分布对构件切削加工形状精度的影响，提出对称分层铣削工艺方法实施切削变形控制。针对大尺寸柔性件形状检测评价和偏差溯源的难题，通过建立梁缘条切削变形与后缘组件装配变形的模式匹配关系，实现大型薄壁构件切削加工形状精度的准确评价和切削变形偏差源诊断，指导梁缘条切削加工形状精度补偿策略。

关键词：大型构件；残余应力；铝合金厚板；切削；装配

Abstract：The rapid development of modern aviation industry requires the high speed， high mobility， heavy load and service performance for aero-parts. It is the challenge that improving the strength and efficiency of aircraft structure while reducing the parts weight. Therefore， a new generation aircraft industry generally adopts the milling technology to obtain the large integrated parts with complex cavity， ribs and bosses， such as the integral panel， the horizontal stabilizers beam flanges， frame and other large complicated structures. It is the roadmap of the project that controlling the residual stress in the whole manufacturing process. Several analyzing models such as the machining surface quality of thin wall component， residual stresses transfer under high speed cutting， cutting forces and thermal coupling prediction is constructed. The correlation analysis of machined surface integrity and fatigue crack initiation is studied by considering the surface residual stress in the cutting process. In order to meet precision requirements of the large thin-walled components， releasing and re-distributing of the residual stress during the course of high-speed milling process， the symmetric layered milling method is proposed and good results are obtained. In order to locating the root causes of assembly deformation for large size flexible parts， the pattern matching method based on the principle components analysis is proposed.

Keywords：Large structure； Residual stress； Thick Aero-Aluminum-Alloy Plate； Machining； Assembly