DYNAMIC PROPERTIES OF GOLDEN DELICIOUS AND RED DELICIOUS APPLE UNDER NORMAL CONTACT FORCE MODELS

Dynamic forces cause the most bruise damage during fruit transport and handling. In order to reduce this damage, it is necessary to model the impact forces. Limited information is available in the literature about the behavior dynamic and dynamic modeling for apple. The normal force-displacement relationship between a viscoelastic sphere (fruit apple) and an impactor was analyzed using the Kuwabara and Kond and Tsuji models as normal force models. Fruits were subjected to dynamic loading by means of a pendulum at impact levels. In order to estimate the parameters (spring, k and damping, c) of the mentioned models for normal impacts, the nonlinear least squares technique (optimization method) was used. Practical ApplicationsA very promising approach for the simulation of fruit impact damage during transport and handling is the contact force discrete element method (DEM). In order to do so, models for the forces acting between particles (like fruits) in contact need to be specified. Forces acting between the two particles are decomposed into normal and tangential components. In this paper, the focus is set on normal contacts. The presented research determines the parameters of normal contact forces models suited for DEM simulation of viscoelastic materials (fruit).