DETERMINATION OF LIMITING HOLE-FLANGING COEFFICIENT IN AA1050-O ALUMINUM ALLOY SHEETS USING THE COCKROFT-LATHAM DUCTILE FRACTURE CRITERION

Abstract

Hole-flanging is a crucial operation in sheet metal forming technology, where the material around a pre-fabricated hole is deformed by a spherical, conical,
or cylindrical punch to create a flanged hole wall. This study aims to determine the limiting hole-flanging coefficient of AA1050-O aluminum alloy sheet using
the Cockroft-Latham ductile fracture criterion. Numerical simulations of the hole-flanging process using the Cockroft-Latham ductile fracture criterion were
conducted to identify the limiting hole-flanging coefficient of AA1050-O aluminum alloy sheet. The limiting hole-flanging coefficient of the material was found
to be 0.61 and was further verified through experiments. Additionally, the effects of the hole-flanging coefficient on the Cockroft-Latham damage value,
minimum thickness, and height of the flanged hole wall were evaluated within the formability region of the material when the coefficient exceeded the limiting
value. The findings from this study provide valuable insights for designing hole-flanging operations for AA1050-O aluminum alloy sheet.