Song Yooseob, Garcia-Gonzalez Daniel, Rusinek Alexis
Department of Civil Engineering, The University of Texas Rio Grande Valley, 1201 W University Dr, Edinburg, TX 78539, USA.
Department of Continuum Mechanics and Structural Analysis, University Carlos III of Madrid, Avda. de la Universidad 30, 28911 Leganés, Madrid, Spain.
Materials (Basel). 2020 Apr 10;13(7):1794. doi: 10.3390/ma13071794.
A new constitutive model for Q235B structural steel is proposed, incorporating the effect of dynamic strain aging. Dynamic strain aging hugely affects the microstructural behavior of metallic compounds, in turn leading to significant alterations in their macroscopic mechanical response. Therefore, a constitutive model must incorporate the effect of dynamic strain aging to accurately predict thermo-mechanical deformation processes. The proposed model assumes the overall response of the material as a combination of three contributions: athermal, thermally activated, and dynamic strain aging stress components. The dynamic strain aging is approached by two alternative mathematical expressions: (i) model I: rate-independent model; (ii) model II: rate-dependent model. The proposed model is finally used to study the mechanical response of Q235B steel for a wide range of loading conditions, from quasi-static loading ( ε ˙ = 0.001 s - 1 and ε ˙ = 0.02 s - 1 ) to dynamic loading ( ε ˙ = 800 s - 1 and ε ˙ = 7000 s - 1 ), and across a broad range of temperatures ( 93 K - 1173 K ). The results from this work highlight the importance of considering strain-rate dependences (model II) to provide reliable predictions under dynamic loading scenarios. In this regard, rate-independent approaches (model I) are rather limited to quasi-static loading.
提出了一种考虑动态应变时效影响的Q235B结构钢本构模型。动态应变时效极大地影响金属化合物的微观结构行为，进而导致其宏观力学响应发生显著变化。因此，本构模型必须考虑动态应变时效的影响，才能准确预测热机械变形过程。所提出的模型假设材料的整体响应由三种贡献组成：无热、热激活和动态应变时效应力分量。动态应变时效通过两种不同的数学表达式来描述：（i）模型I：与速率无关的模型；（ii）模型II：与速率相关的模型。最终，所提出的模型被用于研究Q235B钢在从准静态加载（ε˙ = 0.001 s-1和ε˙ = 0.02 s-1）到动态加载（ε˙ = 800 s-1和ε˙ = 7000 s-1）以及广泛温度范围（93 K - 1173 K）的各种加载条件下的力学响应。这项工作的结果突出了考虑应变率依赖性（模型II）对于在动态加载场景下提供可靠预测的重要性。在这方面，与速率无关的方法（模型I）相当局限于准静态加载。
