Fracture Loci in Sheet Metal Forming: A Review
来源期刊：Acta Metallurgica Sinica2015年第12期
论文作者：M.Beatriz Silva Kerim Isik A.Erman Tekkaya Paulo A.F.Martins
文章页码：1415 - 1425
摘 要：Fracture in sheet metal forming usually occurs as ductile fracture, rarely as brittle fracture, at the operating temperatures and rates of loading that are typical of real processes in two different modes:（1） tensile and（2） in-plane shear（respectively, the same as modes I and II of fracture mechanics）. The circumstances under which each mode will occur are identified in terms of plastic flow and ductile damage by means of an analytical approach to characterize fracture loci under plane stress conditions that takes anisotropy into consideration. Fracture loci was characterized by means of the fracture forming limit line and by the shear fracture forming limit line in the fracture forming limit diagram. Experiments were performed with single point incremental forming and double-notched test specimens loaded in tension, torsion and in-plane shear give support to the presentation and allow determining the fracture loci of AA1050-H111 aluminium sheets with1 mm thickness. The relation between fracture toughness and the fracture forming limits was also investigated by comparing experimental values of the strains at fracture obtained from a truncated conical part produced by single point incremental forming and from double-notched test specimens loaded in tension.
M.Beatriz Silva1，Kerim Isik2，A.Erman Tekkaya2，Paulo A.F.Martins1
1. IDMEC, Instituto Superior Técnico, Universidade de Lisboa2. Institute of Forming Technology and Lightweight Construction, Technical University of Dortmund
摘 要：Fracture in sheet metal forming usually occurs as ductile fracture, rarely as brittle fracture, at the operating temperatures and rates of loading that are typical of real processes in two different modes:（1） tensile and（2） in-plane shear（respectively, the same as modes I and II of fracture mechanics）. The circumstances under which each mode will occur are identified in terms of plastic flow and ductile damage by means of an analytical approach to characterize fracture loci under plane stress conditions that takes anisotropy into consideration. Fracture loci was characterized by means of the fracture forming limit line and by the shear fracture forming limit line in the fracture forming limit diagram. Experiments were performed with single point incremental forming and double-notched test specimens loaded in tension, torsion and in-plane shear give support to the presentation and allow determining the fracture loci of AA1050-H111 aluminium sheets with1 mm thickness. The relation between fracture toughness and the fracture forming limits was also investigated by comparing experimental values of the strains at fracture obtained from a truncated conical part produced by single point incremental forming and from double-notched test specimens loaded in tension.
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