基于XFEM的汽车铝合金断裂行为表征  

Fracture Behavior Characterization of Automotive Aluminum Alloy Based on XFEM

作　　者：张彪[1] 刘家招 杨鑫三 孙宇萱 ZHANG Biao;LIU Jiazhao;YANG Xinsan;SUN Yuxuan(School of Mechanical Engineering,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学机械工程学院,南宁530004

出　　处：《材料导报》2024年第19期219-223,共5页Materials Reports

基　　金：广西科技基地和人才专项(桂科AD22035912);广西制造系统与先进制造技术重点实验室课题(22-035-4S016)。

摘　　要：车用铝薄壁合金5052H32和6061T6以其优异的成形性被广泛用于轻量化车身的冲压钣金件和结构件中。为建立反映材料实际力学特性的表征模型,针对其非线性本构响应中的弹塑性变形、损伤演化及韧性断裂不同发展阶段,分别开发出J-C弹塑性模型、损伤控制模型,以及与应力集中状态相关的J-C失效模型、GTN细观损伤模型和MMC断裂模型,并以参数反演、遗传算法寻优等手段标定了各模型的有效参量,形成力学演变全过程表征。利用上述模型结合扩展有限元法精确模拟了薄壁试件拉伸断裂的过程,通过与实验一致的内部裂纹动态生长行为、应变场和断口形貌,验证了所提取本构性能参数的准确性,且采用经验MMC准则的预测精度最高,形变误差仅为4.7%。Automotive thin-wall aluminum alloys 5052H32 and 6061T6 are widely used in the stamping sheet metal parts and structural parts of lightweight car bodies due to their excellent formability.To establish behavior characterization models reflecting the actual mechanical properties of materials,aiming at different development stages of elastoplastic deformation,damage evolution and ductile fracture in their nonlinear constitutive responses,J-C elastoplastic model,damage control model and J-C failure model,GTN meso damage model,MMC fracture model related to stress concentration state were developed respectively.The effective parameters of each model were calibrated by means of parameter inversion and genetic algorithm optimization to form the whole process characterization of mechanical evolution.Using the above models combined with extended finite element method,the tensile fracture process of thin-wall specimens was accurately simulated.The accuracy of the extracted constitutive property parameters was verified through the dynamic growth behavior of internal crack,strain field and fracture morphology consistent with the experiments.And the fracture prediction accuracy using the empirical MMC criterion reached the highest,with a deformation error of only 4.7%.

关 键 词：车用铝合金 力学表征 损伤 断裂模型 扩展有限元 

分 类 号：U463.326[机械工程—车辆工程]