Analysis and evaluation of a fruit bin for apples.

A fruit bin is an essential part of apple harvesting, storage, and transport. The lateral pressure distribution on the bin walls by apples in the bin are not well understood, thus making it harder to predict the behavior of the vertical walls of the bin. In this study, a bin was loaded with apples and deflections of the base and a vertical wall were experimentally measured and then modeled using finite element methods to understand typical static load distribution. One of the factors determining the accuracy of an analytical model is accurate representation of load distribution on the structure. A mathematical model was used to validate the lateral pressure distribution applied by the apples on the vertical walls and the bottom plate of the bin. The effect of unit weight of an apple and the angle of repose of apples on load distribution in the bin has been analyzed. Angle of repose is found to be a significant parameter for the lateral pressure distribution on the bin walls. A nonlinear lateral pressure distribution was observed along the depth from top to bottom of the bin. The resulting finite element model allows for comparison of deformation behavior of fruit bins constructed with a variety of materials, such as plywood, wood plastic composites, or a thermoplastic polymer. Although this study dealt with bins for apples, the sensitivity analyses for a range of unit weights and angles of repose for apples makes the analysis results versatile for use with other kinds of fruits and vegetables that fall within the reported range of unit weight and angle of repose.