INSTABILITY BEHAVIOR OF METAL SHEETS AND

LIMIT STRAINS ON THE LEFT OF FLD

Chen Guangnan 

(Institute of Mechanics, Chinese Academy of Sciences)

Shen Huan 

(Research Institute of Iron & Steel, Wuhan Iron & Steel Company)

Hu Shiguang

(Beijing University of Aeronautics and Astronautics)

Abstract: The instability behavior of two kinds of metal sheets is experimentally studied on the left of FLD, [-R/(1-R)≤ρ＝dε2/dε1<0]. The experimental results show that the in homogeneity of the strain distribution of the sheets increases with deformation, after the load instability (dp=0), the strain state of the centre region of the specimens, where the tensile strain is the biggest, gradually drifts to the plane strain state, and the localized instability occurs at dε2＝0. Based upon the experimental results, a now model of tensile instability is presented, and the computed results according to this model are coincident with the experimental curves.
Key words: Deformation  Metal sheet  Instability  Limit strain
国家自然科学基金资助项目. Received 19910506, received in revised form 19920601