Study on Damage Characteristics of Loquat Based on Test and Finite Element Method

Loquat (Eriobotrya japonica) has extremely high nutritional and medicinal values. However, it is highly susceptible to compressive damage during picking and postharvest handling. This study aims to establish a finite element model to investigate the damage characteristics of loquats under different contact shapes (circle, cirque, dot, and square) and various loads. Material properties of the pericarp and flesh, including elastic modulus and biological yield stress, were measured through tensile and compression tests. A multiscale model of a loquat composed of pericarp, flesh, and core was established using image processing techniques. In compression damage experiments on loquats, the maximum loads that loquats could withstand under circle, cirque, dot, and square contact shapes were measured as 23.39 N, 15.51 N, 11.67 N, and 9.51 N, respectively. The linear fitting coefficients (R²) of force-damage volume were determined to be 0.97, 0.88, 0.96, and 0.98, respectively, indicating a positive linear correlation between force and damage volume. A comparison between simulations and experiments showed that the minimum and maximum errors in damage volume were 3.7% and 18.6%, respectively. The results confirm that the finite element method is reliable for predicting fruit compression damage, providing a theoretical framework for the development of automated equipment for subsequent processing.