This study concerns the effect of applied velocity on the energy state and stress state related to the puncture-cutting of soft material. A finite element modeling (FEM) of combined puncture and cutting of neoprene rubber by a pointed blade was established at 17 velocities (from 10mm/min to 1500mm/min). The proposed FEM takes into consideration, the nonlinear material behavior of the elastomeric substrate. First, puncture-cutting tests are conducted and the evolution of puncture-cutting force with increased velocity is investigated. Second, the commonly used puncture-cutting energy criterion, including the fracture toughness of material and the friction energy occurring between the material and the pointed blade, are summarized and analyzed. Finally, an analysis of the stress state in the fracture process zone is proposed. Results show that the puncture-cutting force increases significantly with increasing insertion velocity. A low velocity of the pointed blade is dominated by a uniaxial tension with a constant energy, while a medium velocity causes a dominant biaxial tension with increasing energy, which may be the source of the viscoelastic deformation involved around the crack tip. However, an increase of the velocity increases the shear stress up to a maximum value and, therefore, shows a toughening of material.

中文翻译：

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混合断裂的有限元研究：尖刀片插入软材料的速度相关

本研究涉及施加速度对与软材料穿刺切割相关的能量状态和应力状态的影响。在 17 种速度下（从 10毫米/分钟至 1500毫米/分钟）。所提出的 FEM 考虑了弹性体基板的非线性材料行为。首先，进行了穿刺测试，并研究了穿刺力随速度增加的变化。其次，对常用的穿刺切割能量准则，包括材料的断裂韧性和材料与尖刃之间的摩擦能进行了总结和分析。最后，对断裂过程区的应力状态进行了分析。结果表明，随着插入速度的增加，穿刺切割力显着增加。尖刃的低速以恒定能量的单轴张力为主，而中等速度导致能量增加的双轴张力为主，这可能是裂纹尖端周围粘弹性变形的来源。然而，速度的增加将剪切应力增加到最大值，因此显示出材料的增韧。