Formation and evolution of apple (Malus pumila Mill.) bruising based on high-speed camera verification and finite element method

Abstract

To analyse the characteristics and internal mechanical changes of bruising formed on apples under different working conditions, this paper explored the formation mechanism of bruising using finite element method. A composite model of peel and flesh was established by reverse engineering, and the accuracy of the apple model was validated two aspects: drop velocity and bruise volume, with a maximum error of 2.51 %. The collision velocity, contact force, stress, and energy of apple bruising were analysed using commonly used contact materials (wood and rubber) at falling heights of 600, 900, 1200, 1500, 1800, and 2100 mm. The characteristics of apple bruising after formation were analysed and the susceptibility of apple bruising were explored. The findings suggest that as the height increased, so does the maximum stress and bruise susceptibility. At a height of 2100 mm, the apple’s bruise susceptibility was measured at 24955.87 mm3 J−1 (wood) and 24710.18 mm3 J−1 (rubber), respectively. This study offers valuable insights into understanding the mechanism behind bruising in fruits, and has a guiding role in the control of bruising and the optimal design of related machinery.