Prediction of Forming Limit Diagram for Ti-64 titanium alloy sheet using finite element simulation

The use of Ti-64 titanium alloy has been expanded in the aerospace industry because of its unique properties such as lightness and stability at high temperatures. Unusual mechanical behaviors such as plastic anisotropy and asymmetry of tension and pressure of Ti-64 Titanium alloy is observed in different directions. In this paper، by choosing the appropriate yield criterion، isotropic work hardening and return mapping numerical method، elastic-plastic model is implemented using finite element analysis in Abaqus software and prediction of forming limit diagram at 400C° is done using Hill-Swift elastic-plastic theory and random finite element analysis. Material inhomogeneities are considered as random plate thickness field in the stochastic finite element analysis. Considering the effect of step size on accuracy of solution، appropriate step size is applied to prediction of forming limit diagram. Selecting 99% safety percentage in stocastic finite element analysis، the appropriate variance of the random field is considered and is used in predicting forming limit diagram. Also، effects of plastic anisotropy of Ti-64 titanium alloy sheet have been studied in forming limit diagram.