Strain Slip-line Field Research Articles

Blank Development and Tooling Design for Drawn Parts Using a Modified Slip Line Field Based Approach

Box shaped parts demonstrate unusual characteristics as opposed to the drawn cylindrical cups. A novel approach for blank development, based on the modified plane strain slip line field (SLF), is presented in this work. The approach is to balance the element volume between the final position in the wall and the starting position in the flat flange. The end result of this SLF based unfolding technique is a set of elements representing the deformation path of the part. By post-processing the information on the nodal coordinates and invoking the variational principle in its incremental form, the strain distribution in the flange and the wall stresses are determined. A methodology is also presented for understanding the implications of the metal flow lines for tooling design.

Collapse loads for thin cantilevers with rectangular holes along the centre-line

Plane stress slip-line field solutions, which provide the modes of yielding and the corresponding yield loads, are presented for the plastic bending of end-loaded thin cantilevers of rectangular cross-section containing rectangular holes. The theoretical results obtained from these solutions are compared with some experimental results and those obtained from plane strain slip-line fields and lower bound estimates, all presented previously by the authors (1)‡. It is observed that the correlation of the experimental results was much better with the plane stress solutions than with either the plane strain or lower bound results. The effect of adjacent holes and possible lateral or local buckling on the ultimate strength of the cantilevers is also examined.