In this paper we investigate flow localization in viscoplastic slender bars subjected to dynamic tension. We explore loading rates above the critical impact velocity: the wave initiated in the impacted end by the applied velocity is the trigger for the localization of plastic deformation. The problem has been addressed using two kinds of numerical simulations: (1) one-dimensional finite difference calculations and (2) axisymmetric finite element computations. The latter calculations have been used to validate the capacity of the finite difference model to describe plastic flow localization at high impact velocities. The finite difference model, which highlights due to its simplicity, allows to obtain insights into the role played by the strain rate and temperature sensitivities of the material in the process of dynamic flow localization. Specifically, we have shown that viscosity can stabilize the material behavior to the point of preventing the appearance of the critical impact velocity. This is a key outcome of our investigation, which, to the best of the authors’ knowledge, has not been previously reported in the literature.

在本文中，我们研究了在动态张力作用下的粘塑性细长杆中的流动局部。我们探索了高于临界冲击速度的加载速率：在冲击端由施加的速度引发的波是塑性变形局部化的触发因素。使用两种数值模拟解决了该问题：（1）一维有限差分计算和（2）轴对称有限元计算。后者的计算已用于验证有限差分模型描述高冲击速度下塑性流动局部化的能力。由于其简单性而突出的有限差分模型使您能够洞悉材料的应变率和温度敏感性在动态流局部化过程中所起的作用。具体而言，我们已经表明，粘度可以使材料的性能稳定到防止出现临界冲击速度的程度。这是我们调查的关键结果，据作者所知，以前尚未在文献中进行报道。