回转包装容器吹塑成型变径部分应力应变分析

Stress-strain analysis on variable radius section in revolving packing container blowing

采用应力应变分析方法研究回转包装容器吹塑成型变径部分尺寸和性能的影响因素。根据塑件的几何形状和吹塑成型过程把变径区划分为4个成型阶段,在变形区取带状微元根据平衡方程求得沿切向和周向的应力表达式。利用本构方程和总应变条件求得切向、周向和法向的应变值,分析应力比对变形区的成型趋势。以一白酒壶的成型为例,利用划线方法验证该成型趋势的正确性。结果表明,当切向平均半径绝对值大于一定值时,可以形成稳定的变径和大径部分。

Influencing factors on the dimensions and the performance of the variable radius section of packing container were investigated using stress-strain method. The variable-radius section was di- vided into four stages according to the geometrical profile and blowing process. The equilibrium equation for tangential and circumferential stresses were deduced with sliced micro-elements. The tangential, circumferential and normal strains were calculated using constitutive equation and total strain condition, and the blowing intension was analyzed. The intension was validated by marking on the extrusion profile. The results show that the variable radii and final radius can be correctly processed when the average tangential radius is larger than a threshold value.