%0 conference lecture %@ %A Siegmund, T., Bernauer, G., Brocks, W. %D 1998 %J ECF 12: Fracture from Defects; Proceedings of the 12th Bienniel Conference on Fracture - ECF 12 %P 933-938 %T Two models of ductile fracture in contest: porous metal plasticity and cohesive elements %U %X