On stretch and shrink flanging of sheet aluminium by fluid forming

Abstract

In this investigation, vertical stretch and shrink flanging of sheet aluminium by fluid forming are studied experimentally and theoretically. The theoretical part comprises both analytical modelling and finite-element simulations. The fracture limit in stretch flanging is determined by the plastic strain ratio, the strain hardening exponent, and the uniform strain. The greater the magnitude of these parameters, the greater will be the fracture limit. The maximum applied pressure determines the ‘wrinkling’ limit in shrink flanging by fluid forming. The greater is this pressure, the greater ‘wrinkling’ limit. This limit is certainly several times greater in magnitude than that in shrink flanging by conventional tools (a rigid punch and die).