Modal vibration response of rice combine harvester frame under multi-source excitation

Abstract

When a rice combine harvester operates in the field, its frame vibrates significantly under multi-source excitation forces which can cause complex vibration and structural deformation. The vibration response of combine harvester frame under multi-source excitation was deduced. Based on the multi-source excitation of combine harvester, the chassis frame and the threshing frame were assembled into a complete combine harvester frame, which was used to analyse the constraint modal characteristics and its internal connection. A dynamic model of the combine harvester frame as a 7-degrees of freedom rigid body was developed to obtain modal shape and frequency. The excitation parameters of the dynamic model and its vibration response were developed in MATLAB. Vibration response of rice combine harvester frame was tested to verify the dynamic model. By comparing the independent modal frequency of the chassis frame and threshing frame with that of the complete combine harvester frame, the constant modal frequency of complete combine was shown to be directly related to the independent modal frequency of the chassis frame and the threshing frame. The amplitude of signal simulated by the vibration model of combine harvester frame was consistent with the measured amplitude of the frame, which verified the validity of the dynamic model. The six orders constant modal frequencies of the combine harvester frame were within the operating frequency range that could cause complex vibration coupling and resonance. Vibration response of rice combine harvester frame under multi-source excitation could provide a reference for further improvements in the combine harvester frames.