Prediction of fold defect in barreling formations of cylinder upsetting
In this paper, the use of finite element method in conjunction with abductive network is presented for investigating fold defect that may occur in barreling formation during cylinder upsetting with hollow die. Different geometrical conditions combined with various frictional constraints are taken into account as the process parameters in this study. During the upsetting process, several barrels may be successively formed along the lateral free surface of the workpiece and the extrusions of the free surfaces of the billet into the aperture surfaces within the dies are accompanied. In addition, there are two locations where fold defect may occur during upsetting process, one occurs around the equatorial plane of the workpiece and the other takes place around the intersection zone of the barrels. A finite element based code is utilized to investigate the material flow characteristics resulting in the occurrence of fold defect, and the abductive network is then applied to synthesize the data sets obtained from the numerical simulation. Finally, a prediction model is established for fold occurrence judgment around different locations under various combinations of process parameters.
fold defect barreling abductive network