摘要
失稳理论是FLC的理论基础。文章论述了FLC理论研究中存在的问题。指出:一般出厂板的表面状况不会影响板料的集中失稳;板内损伤平面应变时最严重。双拉时,板内损伤的积累、发展,导致应力状态向平面应变漂移;拉压时,载荷失稳后引起的双拉,也会导致平面应变。因此平面应变状态的出现是板料集中失稳的共同原因。在此基础上提出了建立FLC的统一的模型。
A very important tool in the description of sheet metal formability is the well known forming limit curve(FLC).prediction of which is generally based on models using instability theories.Our experimental observations indicat that the surface roughness of as-received metal sheets generally does not lead to strain localization.At the same level of effective strain,the internal damage of a metal sheet is the most severe situation in plane strain state.When deformation is at tension state,damage development results in the drifting of the strain state to plane strain state.When deformation is at tension compression state,the stretch caused by load instability also lead to the development of plane strain state.Based on these results.a united model for the construction of both the left and right half of FLC is proposed.FLCs predicted by the new model math well with experimental results and the new model is proven to be better than the M-K theory.
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
1992年第4期48-53,共6页
Journal of Beijing University of Aeronautics and Astronautics
基金
国家自然科学基金
国家教委博士点基金
航空科学基金
关键词
成形极限曲线
损伤
屈曲
forming limit,instability,damage.
