基于可变杆元数连杆-弹簧模型的复杂引线成形过程建模与仿真

Modeling and simulation of complex looping process based on variable-length link-spring model

为探究引线形成机理,建立可变杆元数连杆-弹簧模型,在该模型中,金线表示成刚性连杆和扭转弹簧依次相连而成,用扭转弹簧的扭转变形来描述金线的弹塑性变形。该模型可动态增减连杆-弹簧数,从而可实现引线成形过程引线长度不断变化的上升阶段的仿真,模型中力矩平衡方程数随连杆-弹簧数变化而动态增减,通过求解模型中的非线性方程组,可得到劈刀在不同位置时的弧线形状。基于该模型分析复杂弧线动态成形过程,模型仿真结果发现反向运动形成折点并影响折点的位置和形状,上升阶段的弧线形状很大程度决定最终弧线形状。通过对比,仿真弧线与实验弧线吻合很好,这表明考虑劈刀上升阶段的可变杆元数连杆-弹簧模型能获得可靠的仿真结果。

To provide insight into the loop formation mechanism, a variable-length link-spring （VLLS） model was proposed. In this model, gold wire was represented as links and torsional springs connected to each other. The deformation of gold wire was. described by the deformation of torsional spring. The wire segments and moment balance equations were dynamically added at the free end as the wire length was increased in the upward stage. The loop profile at different moments was obtained by solving nonlinear equations. The dynamic looping process of complex loop was analyzed with this model. The results show that kink number, position and deformation are influenced by the reverse motion, and that the final loop profile is largely determined in the upward stage. The simulation result agrees with that of the experiment, which shows that the variable-length link-spring （VLLS） model, considering the upward stage, is reliable for the looping process analysis.