FINITE-ELEMENT STUDY OF THE MELON FOR NONDESTRUCTIVE SENSING OF FIRMNESS

'Galia' melons were measured for their physical properties including s hape and firmness, as well as the relation between the static and dyna mic elastic modulus of the melon flesh. A four-layer linear elastic fi nite element (FE) model of the melon was established. Four mode shapes were found to exist, Of these, the breathing mode is typical for melo ns and the remaining three modes are common to other fruits. The stiff ness factors f(2)m and f(2)m(2/3) can be used to evaluate the melon fi rmness where f is their resonant frequency and m the melon mass. The f ormer(f(2)m) is for the melons that are similar in size while the late r (f(2)m(2/3)) is for the melons that are similar in density but diffe r considerably in size. Influence of the watercore on the mode shapes and corresponding resonant frequencies was investigated, Qualitative d etection of these defects is possible by monitoring the change of the mode shapes.