Quantity assessment of plastic deformation energy under impact loading conditions of selected apple cultivars

• A method for calculating plastic deformation energy was presented.
• Bruise susceptibility in apple increased with increasing impact velocity.
• The coefficient of restitution allowed to determine the beginning of the bruise.

This paper presents a new method for plastic deformation energy calculation under impact loading conditions. It consisted in determination of the difference between the values of the absorbed energy from both force-deformation course and the formulae for kinetic energy before and after the impact. Using a high speed camera and a piezoelectric force sensor as two independent measuring systems made it possible. This enabled direct recording of deformation and force response during the apple impact against a rigid, flat surface. For the tested cultivars the increasing relationship between the plastic deformation energy and the impact velocity was obtained. The coefficient of restitution was an appropriate parameter which allowed to determine the initial apple bruising. The increase of apple bruise susceptibility with the increasing impact velocity was also found.