(山东理工大学 机械工程学院，淄博 255000)
摘 要: 对板材理想自弯曲挤出过程的平面应力分析得到出口速度分布与弯曲曲率半径的关系，并提出一种铝合金板材自弯曲挤压新工艺，通过设计异形导流腔结构，使模腔内金属产生不均匀流动，从而直接挤出弯曲型材；采用有限元模拟，分析了板材挤压过程的自弯曲变形机理、金属流动特点以及残余应变的分布；通过选取型腔结构因子与挤压速度为设计变量，采用拉丁超立方抽样方法结合模拟计算，建立了挤出型材弯曲曲率半径的响应面预测模型，在指定弯曲半径为1900 mm的条件下，建立附带罚函数的目标函数优化模型，利用粒子群算法得到最优模腔结构与工艺参数，并进行挤压试模实验。实验结果显示，板材挤出时弯弧稳定，测得曲率半径为2071 mm，弯曲板材内外侧晶粒大小均匀。
关键字: 铝合金；弯曲板材；自弯曲成形；关系推导；机理分析；优化设计
（School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China）
Abstract:Based on the theory of continuum mechanics, the relationship between the exit velocity distribution and the radius of curvature of the plate during the ideal self-bending process is obtained. A new process for the self-bending extrusion of aluminum alloy plates was proposed. By designing the structure of special-shaped guide cavity, the uneven flow of metal in the die cavity was produced, so the bent profile is directly extruded. By using numerical simulation, the self bending deformation mechanism, metal flow characteristics and distribution of residual strain in the process of sheet profile extrusion were analyzed. The response surface prediction model of each variable to the radius of curvature of extrusion self bending was established by using the Latin hypercube sampling method and the finite volume method. Under the condition of a specified bending radius of 1900 mm, an objective function optimization model with a penalty function was established. The algorithm obtains the optimal cavity structure and process parameters, and conducts trial experiments. The experimental results show that the self-bending sheet extrusion is stable, the measured radius of curvature is 2071 mm, the grain size inside and outside of the curved sheet is uniform.
Key words: aluminum alloy; bending sheet profile; self bending forming; relation derivation; mechanism analysis; optimal design
