大型構件去除成形中零殘余應力控制

李淑慧

摘要：現代航空工業的快速發展，對飛機高速、高機動性能、高負載和服役壽命提出了越來越高的要求，因此需要在不斷提高飛機結構強度和效率的前提下降低其自身結構重量。為此，新一代飛機普遍采用毛坯直接銑削加工成具有復雜型腔、筋條和凸臺的大型整體結構件，比如整體壁板、后尾梁緣條、隔框等大型復雜結構件，進而對其加工制造質量提出了更加嚴格的要求。 以加工制造過程中殘余應力的傳遞和控制為主線，針對整體薄壁構件表面質量控制要求，以高速切削已加工表面殘余應力的傳遞作為主線，建立高速切削已加工表面在力、熱耦合作用下的殘余應力預測模型，并分析已加工表面完整性與構件疲勞裂紋萌生的關聯機制，從而有效指導切削加工過程表面殘余應力的調整控制。 針對大型整體薄壁構件切削加工形狀精度控制要求，研究大型整體薄壁構件高速銑削加工過程中體殘余應力的釋放和重分布規律，發現厚板毛坯初始體殘余應力的非均勻釋放和重分布對構件切削加工形狀精度的影響，提出對稱分層銑削工藝方法實施切削變形控制。針對大尺寸柔性件形狀檢測評價和偏差溯源的難題，通過建立梁緣條切削變形與后緣組件裝配變形的模式匹配關系，實現大型薄壁構件切削加工形狀精度的準確評價和切削變形偏差源診斷，指導梁緣條切削加工形狀精度補償策略。

關鍵詞：大型構件；殘余應力；鋁合金厚板；切削；裝配

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