An alternative explanation of forming force reduction for forming process submitted to vibration: Influence of the waveform in the viscoplastic domain

Abstract

This article addresses the effects of vibrations on a viscoplastic workpiece applied during the forgingprocess. To achieve this goal, a phenomenological model based on the slice method combined with aNorton–Hoff viscoplastic law is developed. It allows to study the impact of vibration on the reductionof the mean forging load which has been experimentally observed before, and demonstrates that thesensitivity to strain rate is a key parameter. Moreover, based on the model, a new waveform of thevibrations is proposed that enhance the mean forging load reduction. Finite element simulations andexperiments have been performed to evaluate the validity of the model in the case of sinusoidal andtriangular waveforms, and are in good agreement with the analytical model’s predictions.