摘要
随着越来越高的汽车轻量化需求,铝合金板在现代汽车工业中的应用越来越广。在不同加载路径下,包括比例和非比例加载,5754O铝合金板在塑性成形过程中具有复杂的各向异性规律。试验表明5754O铝合金板的各向异性规律随变形量的增加会发生改变,因此在常参数屈服准则理论框架下,基于传统的单一曲线假设难以对5754O铝合金板在整个塑性变形过程中的各向异性行为进行精确描述。鉴于上述问题,并同时考虑到大变形过程中材料变形的稳定性,对Yld2000-2d屈服准则进行改进。基于改进的Yld2000-2d屈服准则和单一曲线假设推导不同方向的单向拉伸应力应变曲线,并与试验结果进行了对比。结果表明,与原始的Yld2000-2d屈服准则不同,基于改进的Yld2000-2d屈服准则,传统的单一曲线假设仍然适用于5754O铝合金板各向异性问题。给出不同强化方式在比例加载路径下的统一性和非比例加载路径下的分散性证明。基于改进的Yld2000-2d屈服准则和等向强化和混合两种强化方式,推导非比例加载路径下板料的应力应变曲线。基于试验结果,验证了推导的理论曲线的精度。实现了5754O铝合金板在比例和非比例加载路径下变形行为的精确描述,为其工业应用提供了重要的理论支撑。
With the increasing demand for lightweight automobiles, the aluminum alloy sheets are becoming more and more widespread in the modern automotive industry. The 5754O aluminum alloy sheet has complex anisotropy rules in plastic forming process under different loading paths, including proportional and non-proportional loading paths. Experimental results show that the anisotropy will change with the increase of deformation. Therefore, it is difficult to describe the anisotropic behavior accurately during the whole deformation process based on single curve hypothesis. Due to this problem, Yld2000-2d yield function is modified considering the stability during the large deformation process. The stress-strain curve along different directions based on the modified yield function and single curve hypothesis. Comparing the theoretical and experimental results, shows that the modified Yld2000-2d yield function fits for the anisotropy of 5754O aluminum alloy sheet based on single curve hypothesis whereas the original Yld2000-2d does not. The unity and variation of different hardening models under proportional and non-proportional loading paths are proved respectively. Based on the modified Yld2000-2d yield function and different loading mods(isotropic and mixed hardening), the stress-strain curves under non-proportional loading paths are deduced. The resulting theoretical curves are validated with experimental results. The anisotropic deformation behaviors of 5754O aluminum alloy sheet under proportional and non-proportional loading paths are described accurately, which will provide important theoretical support for its industrial application.
作者
王海波
门明良
阎昱
李强
万敏
何东
WANG Haibo;MEN Mingliang;YAN Yu;LI Qiang;WAN Min;HE Dong(School of Mechanical and Material Engineering, North China University of Technology, Beijing 100144;School of Mechanical Engineering and Automation, Beihang University, Beijing 100083)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2018年第24期77-87,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金(51475003)
北京市教委青年拔尖人才培育计划
北方工业大学毓优人才
毓杰人才支持计划(718XN154-007)资助项目
关键词
铝合金
各向异性
加载路径
屈服准则
强化模型
aluminum alloy
anisotropy
loading path
yield function
hardening model
