Mathematical Modeling of Cashew Nut Cracking Force

A mathematical model for predicting the exact cracking force of cashew nut was presented based on the existing hertz's theory of contact stress of two bodies under uniaxial compressive load. Hertz equation was adapted to loading of cashew nuts to cracking at three different loading orientations(X, Y, and Z) and two strain rates of 5mm/min and 10mm/min. The average moisture content of the dried cashew nuts was determined at 5% (db.). The physical properties of cashew nut and some mechanical parameters at loading orientations which are required in the derived model were also obtained from the force-deformation curve respectively. A two-sample t-test comparism of experimental cracking force values and that of the existing hertz model were acceptable at 5% probability level which gave good prediction of cracking force during compression. The force required for the design of suitable cashew nut shell cracking machine should be considered at the range of 400-500N at X (width) and Z (thickness) loading orientations, therefore the magnitude of applied force with the loading orientation could determine the extent of mechanical damage and kernel recovery in cracking and separation processes.