Hertz Theory Application in Modeling and Analysis of Mechanical Rupture Force of Cocoa Pod

Cocoa seeds damage is a major problem facing cocoa farmers during breaking process. Hertz's theory on the contact forces was used for prediction of the rupture force just required to break a cocoa pod under compressive load along its lateral axis. Different varieties of cocoa pods were first subjected to compressive forces. Then they were placed on a test bench and subjected to the impact forces of steel mass dropped at different heights. The objective of this study is to improve the productivity of cacao pods breaker predicting the necessary rupture force. The model of the rupture force obtained from Hertz's theory performed good results compared with experimental values measured in the process of breaking the pods. The average ruptures forces of the cacao pods varieties "Criollo", "Forastero" and "Trinitario" have been determined. Rigidity (stiffness) of the pod was obtained from the force-deformation curve. There is a strongest correlation between the pod rigidity and the rupture force.

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