Rheological model of fruit collision with an elastic plate

The problem of a viscoelastic agricultural product colliding with an elastic plate was investigated analytically and the results were verified experimentally, in order to optimize the separation of hard objects from soft ones. Two rheological models developed in the past, one for a collision of an elastic sphere with an elastic plate, and the second for a collision of a viscoelastic fruit with a rigid flat surface, were combined to form an extended model. The extended model is capable of describing the collision of a viscoelastic agricultural product with an elastic plate. Good agreement was found between its predictions and experimental results. In a particular case, separation of stones from potatoes was required. The impact energy of the stones was absorbed by an elastic plate and consequently its restitution coefficient was reduced. The reduction in the restitution coefficient of the stones was sufficient to enable them to be separated from the potatoes. A design of machine for the separation of soft from hard agricultural products could be based on the: developed model, with consideration of the properties of the plate and the products. (C) 2000 Silsoe Research Institute.