A new approach to the determination of plastic flow stress and failure initiation strain for aluminum alloys cutting process
A new approach to the determination of plastic flow stress and failure initiation strain for aluminum alloys cutting process
复制标题
确定铝合金切削过程塑性流动应力和失效起始应变的新方法
DOI：
10.1016/j.commatsci.2014.08.029
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发表时间：
2014-12-01
影响因子：
3.3
通讯作者：
Ren, Chengzu
中科院分区：
文献类型：
--
作者：
Chen, Guang;Li, Jun;Ren, Chengzu
切削过程中的材料流变应力由于其复杂的变形行为而难以通过实验测量。为了确定7075-T6铝合金（7075-T6）切削过程中的流变应力，建立了切削过程的有限元模拟模型和包含塑性准则和失效准则的流变应力理论模型。在稳定塑性阶段，采用考虑绝热温升（ATR）的Johnson-Cook模型计算塑性流变应力，计算应力与有限元模拟应力的相对误差小于4%。在延性破坏阶段，提出了一种基于温度、压力和应变率的改进破坏起裂准则，用于确定切削时的破坏起裂应变。此外，采用基于能量密度的延性破坏准则预测了破坏阶段的流变应力。将提出的理论模型结果与有限元模拟结果相结合，得到了切削过程中的整个流变应力。讨论了切屑层的起裂应变对切削性能的影响。此外，还对一组铝合金（A2024-T351）进行了正交切削模拟，验证了失效起裂应变对切削过程的影响。两种类型铝合金的失效起裂应变预测变化趋势相似，并将预测力和刀屑接触长度与Atlati et al.[9]的实测值进行了比较。最后，间接验证了失效起裂应变的预测及其对刀屑接触行为的影响。(C) 2014 Elsevier B.V.版权所有
Material flow stress in cutting is difficult to measure experimentally due to the complex deformation behavior involved. In this work, a finite element (FE) simulation of cutting and a theoretical flow stress model including plastic and failure criteria were developed to determine the flow stress during aluminum alloy (7075-T6) cutting process. In a stable plastic stage, the Johnson-Cook model considering the adiabatic temperature rise (ATR) was proposed to calculate the plastic flow stress, and the relative errors of the calculated and FE simulated stresses were less than 4%. In the ductile failure stage, an improved failure initiation criterion in terms of temperature, pressure and strain rate was proposed to determine the failure initiation strain in cutting. In addition, an energy-density based ductile failure criterion was used to predict the flow stress in the failure stage. By combining the proposed theoretical model results and the FE simulation results, the entire flow stress during cutting was obtained. The influence of the failure initiation strain of the chip layer on cutting performance was also discussed. In addition, a set of aluminum alloy (A2024-T351) orthogonal cutting simulations were performed to validate the effect of the failure initiation strain on the cutting process. The predicted variation trends of the failure initiation strain for the two types of aluminum alloys were similar, and the predicted forces and tool-chip contact lengths were compared with the measured values in Atlati et al. [9]. Finally, the prediction of the failure initiation strain and its influence on tool-chip contact behavior were validated indirectly. (C) 2014 Elsevier B.V. All rights reserved.