【作者】 何德华； 李东升； 王丽丽；

【Author】 HE De-Hua,LI Dong-Sheng,WANG Li-Li (School of Mechanical Engineering and Automation,Beijing University of Aeronautics and Astronautics,Beijing, 100191,China)

【机构】 北京航空航天大学机械工程及自动化学院；

【摘要】 加载轨迹对飞机蒙皮拉包成形质量有着至关重要的影响。文章基于飞机蒙皮拉包工艺,结合拉形机在有限元平台PAM STAMP 2G中建立拉包工艺过程的有限元等效模型。采用应变控制的方法,通过几何解析确定夹钳的初始加载轨迹及加载范围。采用数值模拟技术和最优化理论相结合的方法,以夹钳的加载轨迹为优化变量,成形极限图(FLD)和厚度减薄率为约束条件,卸载回弹最小化为目标函数,建立飞机蒙皮拉包成形加载轨迹的最优化数学模型。最后,对某型号复杂型面飞机蒙皮应用上述方法进行计算,通过优化前后结果分析,验证飞机蒙皮拉包工艺有限元等效模型的合理性和优化模型的有效性,为飞机蒙皮拉包工艺的设计与分析提供新的思路。更多还原

【Abstract】 Loading trajectory is the key factor for product quality in stretch wrap forming for aircraft skin.First,the equivalent finite element model of stretch wrap forming process considering stretch forming machine for aircraft skin is established in PAM STAMP 2G.Then the geometrical analytic method is adopted to determine the initial loading trajectory of jaws and their range by using strain control.A calculating method is proposed to obtain the best loading trajectory through combination of finite element analysis and optimization algorithms.Here,the optimal mathematics model of loading trajectory in stretch wrap forming for aircraft skin is set up,where the optimal objective was to minimize springback.Loading trajectory of jaws is used as optimal variable,and the forming limit diagram and sheet thinning are selected as constraints so as to avoid fracture and severe thinning during the forming processes.Finally,a complex shaped aircraft skin part is performed according to the proposed approaches.The rationality of the equivalent finite element model and validity of the optimal model are verified through the results after optimization compared with the original.It provides a new path to design and analyze the stretch wrap forming process for aircraft skin.更多还原