Discrete Element Model Building and Optimization of Tomato Stalks at Harvest

Abstract

The mechanical properties of tomato stalk, relevant to the harvesting and crushing of tomato vines, significantly impact its harvesting quality and efficiency. Establishing a simulation model, which accurately mirrors these properties, is foundational for designing related mechanical components. The discrete element method models tomato stalk harvesting and is optimized through mechanical tests and simulations. A blend of Plackett–Burman, steepest ascent, and central composite design modeling identified three contact model parameters influencing the maximum stalk shear force. The optimal values of these three parameters were a normal stiffness of 1.04 × 1010 N m−3, tangential stiffness of 7.59 × 109 N m−3, and bond radius of 1.06 mm. The relative error in the simulated versus measured shear force was <1%, affirming the model’s accuracy in characterizing cutting properties. These findings lay the theoretical groundwork for numerical simulations of tomato-stalk-related equipment.