Model for vibration-cumulative bruising of fruit based on fatigue damage theory

Fatigue vibration is one of the key factors causing fruit bruising during transportation. A model for vibration-cumulative bruising of fruit was developed based on the Palmgren-Miner fatigue damage theory, and the relativity between the bruise properties and vibration excitation were investigated. The fatigue bruising vibration and critical bruising vibration experiments were conducted for crystal pears under sine excitations of varied acceleration and numbers. The parameters of the model for vibration-cumulative bruising of pear fruit were obtained. According to the produce classification standard of China for pear, the critical bruising volume of high-class pear fruit was calculated, and corresponding vibration excitation threshold was presented. The model predictions agreed well with the experimental data. The research results provide technical bases for recognizing the mechanism of vibration-cumulative bruising of fruit and packaging the fruit for relaxing the vibration.