Transient response analysis of the variable frequency cropping system

Abstract

Variable frequency cropping is a new type of green manufacturing technology that utilizes the forced vibration of a cropping machine and the stress concentration effect of a V-shaped notch to produce crack initiation and propagation. In this paper, dynamic analysis of a variable frequency vibration cropping system is performed. First, the working principle and components of a variable frequency cropping system are explained. Further analysis shows that vibration characteristics are the main subject of variable frequency cropping. Second, the orthogonal test method is adopted to assess the influence of geometric parameters of the V-shaped notch on the vibration characteristics of metal bars. The results indicate that a V-shaped notch has little effect on the vibration mode frequency. Third, a finite-element model of the cropping system is constructed, which is composed of rigid bar elements, a beam element, a lumped mass element, and spring elements. Then the modal and dynamic analyses are conducted. The vibration characteristics and the ideal cropping frequency range are obtained on the basis of the results of the dynamic analysis. Finally, cropping experiments on bars made of Al-Cu4MgSi, C45e, C20e, and TC80 are carried out under conditions of three variable frequency curves.