Mechanical and geometrical characterization of fruits Coffea arabica L. var. Colombia to simulate the ripening process by finite element analysis

In this study, a geometric model of Coffea arabica var. Colombia fruits is reviewed to represent computationally the fruit topology in any development stage. A finite element analysis was carried out to estimate Young's moduli for different ripeness stages. Analytical equations were adjusted to experimental data of size, volume and Young's moduli (semi-experimental) with the aim to analyze its behavior in the ripening process. Further, a volume equation is also developed in dependence on the orthogonal variations of the fruit. These variations show that the fruit keeps a growth constant ratio. To simulate the fruit growth, a finite element analysis was performed on an unripe fruit with displacement boundary conditions that enforce the geometric changes. To verify that the volume changes were simulated correctly in each ripeness stage, a strain index was defined to compare the growth evolution with experimental data. Results show that the simulated fruit growths properly since dimensions and volume were predicted in a reasonable level of approximation. Additionally, the internal pressure was computed for all ripening stages and the results are consistent with the comparisons done from the strain energy of the fruit.