Treatment of element distortion for ring rolling process

To handle the element distortion caused by hourglass in the dynamic explicit simulation of ring rolling,controlling methods in the FEA were studied.A rectangular section ring rolling was simulated.In the initial phase,the hourglass energy and the ring deformation were small.With the ring deformation increasing,much more hourglass energy was required.With the artificial damping method,the needed hourglass energy was about 20% of internal energy,while only 5% was needed with the artificial stiffness method.The internal energy was much less disturbed by the hourglass.with the artificial damping method,the damping factor was between 0.05 and 0.15,while the hourglass energy was the smallest when the 0.1 was adapted.With the artificial stiffness hourglass method,the stiffness factor was between 0.001 and 0.15,When stiffness factor was 0.05,the hourglass energy was the smallest.