A novel multiscale material plasticity simulation model for high-performance cutting AISI 4140 steel
A novel multiscale material plasticity simulation model for high-performance cutting AISI 4140 steel
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DOI：
10.1007/s00170-021-07643-w
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发表时间：
2021-07
期刊：
影响因子：
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通讯作者：
Jinxuan Bai;Z. Tong
中科院分区：
文献类型：
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作者：
Jinxuan Bai;Z. Tong
在高性能切削过程中，可实现的加工表面质量在很大程度上取决于材料的性能。本文建立了多尺度材料塑性模拟框架，用于预测AISI 4140钢在各种高性能切削条件下的变形行为。通过优化基于位错密度（DDB）的本构方程（在ABAQUS中编译为用户自定义子程序），将三维离散位错动力学（3D-DDD）模型与有限元法（FEM）耦合构建框架。利用3D-DDD分析了边位错和螺位错的产生、传播、侧边及其相互作用，并利用位错的统计特征对DDB本构方程的临界常数进行了优化。为了验证，采用经典的有限元切削模型（Johnson-Cook本构方程）作为参考。仿真结果表明，所建立的多尺度模型不仅能准确预测经典有限元模拟预测的应力、应变、切削力和温度，而且能捕捉到切削条件下的微观组织特征，如晶粒尺寸和位错密度分布。在核心剪切区发现了严重的动态再结晶现象。当切削速度大于280 m/min或外部辅助温度在200 ~ 350°之间时，加工表面的再结晶过程达到动态平衡，表明提高表面完整性的最佳加工参数范围。
The achievable machined surface quality relies significantly on the material behavior during the high-performance cutting process. In this paper, a multiscale material plasticity simulation framework is developed to predict the deformation behaviors of AISI 4140 steel under various high-performance cutting conditions. The framework was built by coupling a three-dimensional discrete dislocation dynamic (3D-DDD) model with a finite element method (FEM) through the optimization of a dislocation density-based (DDB) constitutive equation (compiled as a user-defined subroutine in ABAQUS). The movement of edge and screw dislocations such as generation, propagation, siding, and their interactions, was performed by 3D-DDD, and the statistical features of dislocations were used to optimize the critical constants of the DDB constitutive equation. For validation, a classic FEM cutting model (Johnson-Cook constitutive equation) was employed as a reference. The simulation results indicated that the proposed multiscale model not only can precisely predict the stress, strain, cutting force, and temperature as those predicted by the classic FEM simulations, but also capture the microstructure characteristics such as grain size and dislocation density distributions under the tested cutting conditions. Severe dynamic recrystallization phenomena were found at the core shear zones. The recrystallization process reached a dynamic equilibrium at the machined surfaces when the cutting speed is larger than 280 m/min or the external-assisted temperature is between 200 and 350°, indicating an optimal range of machining parameters for improved surface integrity.