Heat sources, energy storage and dissipation in high-strength steels: Experiments and modelling
Heat sources, energy storage and dissipation in high-strength steels: Experiments and modelling
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DOI：
10.1016/j.euromechsol.2009.11.005
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发表时间：
2010-05
影响因子：
4.1
通讯作者：
S. Dumoulin;H. Louche;O. Hopperstad;T. Børvik
中科院分区：
文献类型：
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作者：
S. Dumoulin;H. Louche;O. Hopperstad;T. Børvik
在室温和准静态加载条件下对三种表现出吕德斯带传播的高强度钢进行了拉伸试验。分别通过数字图像相关和数字红外热成像技术测量平板样品表面的位移场和温度场。真实应力与真实应变曲线是根据位移数据计算的，而热数据则用于使用局部热扩散方程来估计热源。根据这些测量，估计存储和耗散的能量直至扩散颈缩。应用热力学一致的弹塑性本构模型（包括 von Mises 屈服准则、相关流动规则和两个非线性各向同性硬化变量）来描述高强度钢的行为。结果表明，这个简单的模型能够重现局部行为（例如与热源相关的功率）和全局行为（例如 Lüders 带传播以及存储和耗散的能量）。进一步表明，耗散功率与塑性功率的比率在塑性应变期间发生变化，并且在数值模拟中很好地捕获了这种变化。
Tensile tests on three high-strength steels exhibiting Lüders band propagation are carried out at room temperature and under quasi-static loading conditions. Displacement and temperature fields on the surface of the flat samples are measured by digital image correlation and digital infrared thermography, respectively. The true stress versus true strain curves were calculated from the displacement data, while the thermal data were used to estimate the heat sources using the local heat diffusion equation. Based on these measurements the stored and dissipated energies were estimated up to diffuse necking. A thermodynamically consistent elastic-plastic constitutive model including the von Mises yield criterion, the associated flow rule and two non-linear isotropic hardening variables is applied to describe the behaviour of the high-strength steels. It is shown that this simple model is able to reproduce both the local behaviour, such as the power associated to heat sources, and the global behaviour, such as Lüders band propagation and stored and dissipated energies. It is further shown that the ratio of dissipated power to plastic power varies during plastic straining and that this variation is captured reasonably well in the numerical simulations.