Explicit dynamics simulation of Pecan fruit deformation under compressive loading-Part-1: Determination of modulus of elasticity

Abstract

This study, which is divided into two parts, introduces an explicit dynamics simulation procedure for Pecan fruit (Carya illinoinensis) deformation under compressive loading. An original application algorithm based on experimental and theoretical methods has been described in the study. The major aim of this Part 1 is to determine the modulus of elasticity through various calculation approaches for Pecan fruit. In addition to this, some engineering properties of the Pecan fruit components were determined to define them as simulation input parameters in an explicit dynamics deformation simulation which is detailed in the second part of the study. The original geometry of the Pecan fruit and its components were digitized using reverse engineering technology (three-dimensional [3D] laser scanning). Force–deformation data, which can describe the physical deformation characteristics of the Pecan fruit components, was collected through experimental compression tests. Initial crack points for the Pecan shell (kernel-in-shell) in these tests were measured as 335.62, 239.42, and 165.03 N for longitudinal, transverse, and suture orientations, respectively. Hooke's, Hertz's, and Boussinesq's theories and finite element method simulation based linear prediction approach based modulus of elasticity calculations were realized. Results from these calculations revealed that loading orientation is an important factor and there were differences between the results of calculation theories (15.2% on average). Practical applications The simulation approach and application algorithm introduced in this two-part study is a scientific novelty because the explicit dynamics simulation approach for Pecan fruit deformation has not previously been reported in the literature. This first part focuses on realistic description (digitizing) of the fruit geometry through a reverse engineering approach and determination of modulus of elasticity (by considering various theories) and some engineering properties of the Pecan fruit components (experimentally). These investigations have important roles in this study so that realistic material models of the fruit components can be described in the simulation study which is presented and detailed in the second part of the study. In this part, it has been experienced that loading orientation is an effective factor for fruit deformation behavior and different theories may provide different results during calculation of the specific mechanical properties. These important findings have been presented in a form which may be used as input parameters in design studies of shelled agricultural product processing machinery systems used in the related industry.