Prediction of Forming Limit Diagram for Ti-6Al-4V Alloy Using Artificial Neural Network

In sheet metal industries, the ability to predict and avoid failures, such as necking, fracture and wrinkling are of great importance. It is important to work within the safe strain region to avoid these failures. The forming limit diagram (FLD) is the most appropriate tool to obtain the safe strain region for every sheet metal in different strain conditions and ration. In this paper, significance of important process parameters namely, punch speed, blank holder pressure (BHP) and temperature on FLD of a Ti-6Al-4V alloy are investigated. Taguchi technique was employed to identify the influence of these parameters on major strain and minor strain. The finite element model of deep drawing process has been built up and analyzed using Dynaform version 5.6.1 with LS-Dyna version 971 as solver. The simulations have been performed in Taguchi order to obtain the values of major strain and minor strain. Furthermore, the values of major and minor strain is predicted using artificial neural network (ANN) considering input parameters as punch speed, blank holder pressure (BHP) and temperature and normalized distance of a cup. Forming limit curve is drawn by using Keeler's equation considering the properties of Ti-6Al-4V at various forming temperatures. It is observed that the predicted strain values are in good agreement with the experimental data.