Numerical analysis of formability of a commercially pure zirconium sheet in some sheet forming processes

To examine the fundamental sheet formability of zirconium, deep drawing, Erichsen and bore-expanding tests are carried out for a commercially pure zirconium sheet. These sheet forming processes are further simulated by the rigid-plastic finite element method, and the forming limits are numerically predicted by means of a criterion for ductile fracture. The material constants in the ductile fracture criterion are determined from uniaxial and plane-strain tension tests. The results show that the drawability of the zirconium sheet is quite high, while the stretchability is low. The forming limits in deep drawing and bore-expanding processes greatly depend on the punch profile radius and remarkably decrease with the radius. Furthermore, it is found that the fracture initiation sites and the forming limits of the zirconium sheet can be predicted fairly well by the combination of the finite element simulation and the ductile fracture criterion.