Investigation of deformation and failure features of AA6082: Experimentation and modelling
Investigation of deformation and failure features of AA6082: Experimentation and modelling
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DOI：
10.1016/j.ijmachtools.2011.07.005
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发表时间：
2012-02-01
影响因子：
14
通讯作者：
Dean, Trevor A.
中科院分区：
文献类型：
--
作者：
Mohamed, Mohamed S.;Foster, Alistair D.;Dean, Trevor A.
本文介绍了一套AA6082板件热冲压和冷模淬火过程中变形与损伤的粘塑性耦合本构方程。该方程集可用于预测热成形条件下AA6082的粘塑性流动和塑性损伤。变形和损伤依赖于一组耦合的不断演变的内部状态变量，例如位错密度，而这些变量又受到热激活和变形相关的再结晶和恢复的影响。基于温度、应变和应变速率的预期物理标度，导出了损伤的现象学描述。在商业软件ABAQUS中，通过用户自定义子程序VUMAT实现了所得方程，进行了成形过程仿真。设计了一个实验方案，并开发了专门的测试设施，用于校准和验证有限元过程建模结果。仿真结果与实验结果吻合较好。这证实了本构方程中的物理依赖关系是正确形成的，并且可以对方程和有限元模型进行校准并用于AA6082板件的热冲压。利用该模型进行成形工艺优化，确定了中间带圆孔的基本板件的最优成形参数。最后讨论了本构模型、实验表征和建模结果对AA6082板件制造的潜在影响。(C) 2011 Elsevier Ltd.版权所有。
This paper introduces a set of coupled viscoplastic constitutive equations for deformation and damage in hot stamping and cold die quenching of AA6082 panel parts. The equation set can be used to predict viscoplastic flow and plasticity-induced damage of AA6082 under hot forming conditions. Deformation and damage depend upon a coupled set of evolving internal state variables, e.g. dislocation density, which in turn is affected by thermally activated and deformation-dependent recrystallisation and recovery. A phenomenological description of damage is derived based on the expected physical scaling with temperature, strain and strain rate. The resulting equations were implemented in the commercial software ABAQUS via the user-defined subroutine VUMAT for carrying out forming process simulations. An experimental programme was designed, and specialised testing facilities developed for calibrating and validating the FE process modelling results. A good agreement between the process simulation and the experimental results has been achieved. This confirms that the physical dependencies in the constitutive equations are correctly formed, and that the equations and FE model can be calibrated and used for hot stamping of AA6082 panel parts. Further, forming process optimisation was carried out using the model to identify the optimal forming parameters for a basic panel part with a circular hole in the middle. The study concludes with a discussion of the potential impact of the constitutive model, experimental characterisation and modelling results on AA6082 panel parts manufacture. (C) 2011 Elsevier Ltd. All rights reserved.