Formability prediction of AL7020 with experimental and numerical failure criteria
Formability prediction of AL7020 with experimental and numerical failure criteria
复制标题
DOI：
10.1016/j.jmatprotec.2014.11.034
复制
发表时间：
2015-04
影响因子：
6.3
通讯作者：
Z. Yue;H. Badreddine;T. Dang;K. Saanouni;A. Tekkaya
中科院分区：
文献类型：
--
作者：
Z. Yue;H. Badreddine;T. Dang;K. Saanouni;A. Tekkaya
铝合金板材的成形性是其设计、分析和制造工艺操作中的一个关键问题。传统的成形极限图(FLD)用来评价失效时的主应变，常被用来量化成形极限。由于成形极限图对应变路径的敏感性，基于主应力的成形极限应力图(FLSD)被证明是更有效的。相比之下，最近提出了一种完全耦合的行为-损伤模型，该模型允许基于适当的描述所涉及的主要物理现象的全耦合本构方程来预测应变局部化和破坏发生。在这项工作中，使用了一个完全耦合的本构方程，该方程考虑了混合的非线性、各向同性和运动硬化与各向同性韧性损伤的完全耦合。微裂纹闭合是为了在大范围的应力状态下影响断裂时的等效塑性应变而增加的。为检验铝合金AL7020的成形性，进行了各种试验。对三种不同的方法(FLD、FLSD和全耦合模型)分别进行了识别和验证。借助Nakazima试验和截面拉深试验，对AL7020的三种失效准则的质量进行了比较和验证，并对模拟结果进行了研究。
The formability of aluminum alloy sheet metal is a key issue in its design, analysis and operation of manufacturing processes. The conventional forming limit diagram (FLD) which evaluates the principal strains at failure is often used to quantify the formability limits. Due to the sensitivity of the FLD to the strain paths, the forming limit stress diagram (FLSD) based on principal stresses is shown to be more efficient. In contrast, a fully coupled behavior-damage models are recently proposed, which allow to predict the strain localization and the failure occurrence based on appropriates fully coupled constitutive equations describing the main physical phenomena involved. In this work a fully coupled constitutive equations taking into account the mixed nonlinear isotropic and kinematic hardenings fully coupled with the isotropic ductile damage is used. The microcracks closure is added to affect the equivalent plastic strain at fracture in a large range of stress states. Various tests are conducted to test the formability of aluminum alloy AL7020. The three different methods (FLD, FLSD and the fully coupled model) are identified and validated separately. With the help of Nakazima tests and cross-section deep drawing tests, the quality of the three failure criteria for AL7020 are compared and demonstrated with the investigations of the simulation results.