On criteria for dynamic adiabatic shear band propagation
On criteria for dynamic adiabatic shear band propagation
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DOI：
10.1016/j.jmps.2006.12.006
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发表时间：
2007-07
影响因子：
5.3
通讯作者：
S. Medyanik;Wing Kam Liu;Shaofan Li
中科院分区：
文献类型：
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作者：
S. Medyanik;Wing Kam Liu;Shaofan Li
本文提出了动态剪切带扩展的物理判据，并在假设基础上实现了动态绝热剪切带（ASBs）的数值模拟算法和计算判据。该物理判据基于剪切带区域内的材料在高温和高应变速率条件下变形期间经历动态再结晶过程的假设。除了提供了一个新的视角的绝热剪切带过程的物理和识别材料的属性，在定义材料的敏感性ASBs中发挥了至关重要的作用，所提出的标准是有助于数值模拟的ASBs的传播时，采用多物理模型来描述和预测复杂的本构行为的韧性材料中的ASBs。系统和大规模的无网格模拟已经进行了测试和验证所提出的标准，通过检查的形成，传播，和后分叉行为的ASB在两种材料，4340钢和OFHC铜。热传导的影响，特别是热传导引入的长度尺度，也进行了研究。数值模拟的结果与实验观察和密切的协议被发现的各种特性的ASB，如剪切带宽度，传播速度，和最高温度进行比较。
In this work, we postulate the physical criterion for dynamic shear band propagation, and based on this assumption, we implement a numerical algorithm and a computation criterion to simulate initiation and propagation of dynamic adiabatic shear bands (ASBs). The physical criterion is based on the hypothesis that material inside the shear band region undergoes a dynamic recrystallization process during deformation under high temperature and high strain-rate conditions. In addition to providing a new perspective to the physics of the adiabatic shearbanding process and identifying material properties that play a crucial role in defining the material's susceptibility to ASBs, the proposed criterion is instrumental in numerical simulations of the propagation of ASBs when multi-physics models are adopted to describe and predict the complex constitutive behavior of ASBs in ductile materials. Systematic and large scale meshfree simulations have been conducted to test and validate the proposed criterion by examining the formation, propagation, and post-bifurcation behaviors of ASBs in two materials, 4340 steel and OFHC copper. The effects of heat conduction, in particular the length scale introduced by heat conduction, are also studied. The results of the numerical simulations are compared with experimental observations and a close agreement is found for various characteristic features of ASBs, such as the shear band width, speed of propagation, and maximum temperature.