Deformation and bruising investigation of the olive fruit in a rotary hand-held olive harvester

Mechanical damage to the olive fruit caused by direct impact of the rotary olive harvesting machine poses a significant challenge for farmers with small orchards. This research investigates the influence of the effective parameters of the RH, which includes the geometrical properties of the impactor rod (flat and round) and the speed of the rod (500, 1000, and 1500 rpm), on the mechanical damage of the olive fruit during the ripening period (unripe, semi-ripe, and ripe) using experimental and numerical methods. A laboratory system was developed to simulate the harvesting process and calculate the created von Mises stress. The impact test was conducted using the developed system, and the amount of mechanical damage at both the macro and micro scales was obtained using a simple microscope and a scanning electron microscope, respectively. Additionally, the finite element method, a well-proven numerical approach, was employed to model the harvesting process. The finite element model successfully predicted the amount of stress at the impact moment, the extent of the damaged area, bruise volume, and bruise susceptibility of the olives under different test conditions. When compared to the experimental method, the maximum simulation errors for von Mises stress, damaged area, bruise volume, and susceptibility were 13.53%, 31.52%, 20.71%, and 19.42%, respectively. His study contributes to further research on the application of explicit nonlinear dynamics in the design and optimization of rotary olive harvester machines, particularly from an industrial perspective.