裂尖超钝化:实验、理论与数值模拟

本文报道了在改性聚丙烯裂尖平面应变段发生超钝化的实验发现。利用环向冷拉模型,可说明裂尖超钝化的形成取决于冷拉传播速率与加载率之比。裂尖超钝化可使材料韧性,尤其是冲击韧性的改善,达到一个新的水平。本文在超弹性-粘塑性各向异性损伤的有限变形本构模型下进行了详尽的数值计算。模拟结果成功地再现了裂尖超钝化的基本特征。

CRACK TIP SUPERBLUNTING: EXPERIMENT, THEORY AND NUMERICAL SIMULATION

Experimental revelation of superblunting along plane strain predominant crack tip segment is reported here for modified polyproplene. As elucidated by a heuristic model of progressive circumferential cold-draw the formation of superblunting crack tip depends critically on the ratio between the cold -draw propagation speed and the loading speed, and contributes significantly to the material toughening,especially for the improvement on impact toughness. Detailed numerical calculations are conducted based on a hyperelastic -viscoplastic and anisotropic damage constitutive model at finite deformation. The simulated results recapitulate the essential features of crack tip superblunting.