1987 Volume 30 Issue 270 Pages 2034-2039
Surface roughening of sheet metals with plastic strain is removed at a given strain during the forming process, and its effect on the improvement of the forming limit is investigated. As a preliminary examination to estimate how the onset of localized necking is delayed by the removal of surface roughness, a rigid-plastic FEM simulation is first made. Experiments for soft aluminium and copper sheets are also carried out, and the increase in forming limit strain is examined for a few strain paths. It is shown that the improvement of the forming limit is considerable in the stretch forming region where the major and minor strains in the plane of a sheet are positive. For balanced biaxial stretching, for example, the forming limit strain can be increased up to about 1.3 to 1.4 times as large as that for ordinary in-plane stretching.
JSME International Journal Series C Mechanical Systems, Machine Elements and Manufacturing
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JSME international journal. Ser. C, Dynamics, control, robotics, design and manufacturing
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JSME international journal. Ser. A, Mechanics and material engineering
JSME international journal. Ser. 1, Solid mechanics, strength of materials