Tube Expansion by Single Point Incremental Forming: An Experimental and Numerical Investigation

In this paper, we revisit the formability of tube expansion by single point incremental forming to account for material strain hardening and non-proportional loading paths that were not taken into consideration in a previously published analytical model process built upon rigid perfectly plastic material. The objective is provide new insight on reason why critical strains at failure are far superior those conventional tapered conical punches. For purpose, replaced stress triaxiality ratio responsible accumulation damage cracking tension monotonic, proportional paths, integral forms more adequate resulting from unloading cycles expansion. Experimental numerical simulation results plotted effective vs. space confirm validity approach handling oscillate cyclically shearing biaxial stretching, as hemispherical tool approaches, contacts moves away specific location incrementally expanded surface.