Effect of Width/Thickness Effect of Sheet Metals on Bendability

The effect of width/thickness ratio on the bendabilityBendability of sheet metal is investigated using the finite element method (FEM)Finite element method (FEM) employing the Gurson–Tvergaard–Needleman (GTN) model. Strain path changes in the sheet with a change in width/thickness ratio. It is shown that bendability and fractureFracture strain increase significantly by a decrease in width/thickness ratio. The stress state is almost uniaxial when the stress ratio (α) is close to zero for narrow sheets. This delays the growth and coalescence of microvoids as the volumetric strain and stress triaxiality decrease. On the other hand, ductility decreases with an increase in α for wider sheets. FractureFracture bending strain is calculated and, as expected, it increases with the decrease in width/thickness ratio. Numerical results are found to be in good agreement with experimental observations.