Damping behaviour of a prestressed composite beam designed for the thresher of a combine harvester

Abstract

During harvesting, the thresher of the combine harvester produces unbalanced vibrations due to problems such as stalk winding and these can greatly affect the stability and service life of the device. Finite element modal analysis and the vibration tests of the threshing cylinder and the frame were carried out. Based on the simulation of the thresher and the analysis of experimental data, four kinds of prestressed support beams were designed to suppress the dynamic characteristics of the thresher during operation. To verify the vibration suppression effect, a vibration test was carried out with the prestressed support beams on installed on the thresher. The results showed that vibration of the threshing device is intensified during threshing and the vibration is mainly transmitted to the entire machine frame through the bearing seats. The four prestressed support beams designed can all can provide dynamic suppression of the threshing device but the triangular beam had the best restraining effect. Thus, properly designed prestressed support beam structures can effectively suppress the dynamic characteristics produced by the thresher during the threshing process. • Vibration state during threshing process tested and compared with no-load. • Threshing support frame can isolate vibration if designed by prestressing method. • Vibration isolation effect of prestressed beams during threshing obtained. • Prestressed beam designs produced suitable damping behaviour.