Crystallographic texture effects in hydroforming of aluminum sheet

The success of hydroforming operations, as well as many other sheet forming processes, depends strongly on the initial condition of the stock material. The stock material may be in a variety of states as a consequence of its processing history. The crystallographic texture may range from a pronounced deformation texture imparted by rolling operations to a cube texture that could arise from recrystallization. Such variations in the texture impose significant differences on the plastic response of the material. To accurately predict the deformations during hydroforming, the effects of the crystallographic texture on the anisotropy of the plasticity must be included in the forming model. In this paper polycrystalline plasticity is used in conjunction with a three-dimensional, transient, finite element formulation to simulate hydroforming. The procedure to initialize the starting state of the material in terms of aggregates of crystals is emphasized as it is as essential element in treating work hardened materials. Massively parallel algorithms are employed to interrogate aggregates for the purpose of evaluating mechanical properties and to update their states. Application to drawing of aluminum sheet using the hydroform process demonstrates the ability of the formulation to capture effects such as earing.