激光刻痕聚丙烯塑料失效破坏的参数识别

采用等效截面积法建立了激光加工微孔的有限元模型及带激光刻痕聚丙烯塑料板的冲击模型,并 通过参数识别方法确定了材料的失效应变。通过极差分析得出该塑料材料的冲击断裂强度随撕裂线直径的 增大而增大,随冲击速度的增大而减小。这与实验结果一致。

Parameter identification of the failure strain of laser scaled polypropylene material

Polypropylene(PP) plastic was reprocessed by laser facility to decrease the local strength around the scored line.The weaken strength is necessary to evaluate to meet engineering requirement.In the present research,the commercial finite element software LS-DYNA was applied to analyze PP’s failure strength under impact.In the FE model,the equivalent section method was applied to approximate the tiny orifices formed by laser.Meanwhile,account for rate-dependent of PP material,six stress-strain curves with different strain rate were given to describe the material.The failure strain was determined through parameter identification approach.Compared with a series of experiments,the numerical results were confirmed.By range analysis of numerical results,it was found that the failure strength increased with the increase of the diameter of seamless line,and it decreased with the increase of the impacting velocity.