Finite element method model of the mechanical behaviour of Jatropha curcas L. bulk seeds under compression loading: Study and 2D modelling of the damage to seeds

• Viscoelastic and visco-plastic properties allow for seed interaction and failure.
• 2D FEM models and experiments in cylinders with different diameters were compared.
• Coefficient of friction significantly affects reorganisation of compressed seeds.
• Special apparatus used to visualise failure of Jatropha seeds under compression.
• Reducing friction between seeds and vessel may increase pressing efficiency.

This article is focused on comprehensive research of a pressing process of Jatropha curcas L. bulk seeds during linear compression. Compression experiments were performed and the strain and brittle fracturing of the seeds visualised. The mechanical behaviour and stress distribution at the volumetric strain of bulk seeds in pressing cylinders and semi-cylinders with diameters of 60, 80 and 100 mm were described by 2D FEM models. It has been determined that the study of nonlinear visco-elastic and plastic strain seed interactions and the damage and crack growth in such seeds can be significantly improved through computer simulations using an explicit FEM algorithm. In this study, the compressibility of ripe J. curcas L. bulk seeds was analysed and compared depending on the volume strain and energy performance of the linear pressing process. Empirical equations and differential deformation theory describing the seeds interacting beyond the oil point were reported. In addition, the issue of contact theory in numerical modelling of the point contact of interacting seeds was also described. Statistical results showed that the 2D FEM model can be used to study the volumetric strain, stress and damage of J. curcas L. bulk seeds. These studies suggest that FEM models may be considered an important tool to assess the energy performance of the pressing process of J. curcas bulk seeds and can provide valuable information for the design and optimisation of pressing equipment.