Failure prediction in incremental sheet forming based on Lemaitre damage model

Single Point Incremental Forming (SPIF) is a dieless forming process. In this process sheet is clamped on its periphery and a hemispherical tool clamped on a CNC (Computer Numeric Control) machine applies small incremental pressure to deform the sheet in three dimensional component. During the process, strain increases on successive steps of forming and it is much above the conventional forming limit. These higher strains lead to excessive thinning which eventually results in failure. The aim of this work is to revisit the failure analysis in SPIF and study the effect of tool diameter on the failure. Finite element method (FEM) is used for the analysis of the process and a truncated cone is simulated using different tool diameter. For failure prediction, Lemaitre damage model, based on continuum damage mechanics, has been numerically implemented in FE software Abaqus/Explicit using user subroutine. Further, the results from numerical analysis such as strain evolution in deformation zone and thickness reduction are analysed.