MODELING THE VIBRATIONAL RESPONSE OF PLANTAIN FRUITS

Plantain fruits of the plantain subgroup (Musa AAB Group) were obtaine d at a green stage and used in this study. The fruits were labelled fo r identification, and stored in a chamber maintained at a temperature of 20C and relative humidity of 90 +/- 4%. On daily basis, for a perio d of 14 days, the fruits were removed from the storage chamber and eac h was weighed to record the mass. They were vibrated vertically on a v ibration exciter through a range of frequencies from 10 to 2000 Hz. Th e frequency response was modeled by a single-degree-of-freedom Kelvin model. The mass of the fruit, the stiffness, the natural frequency and the critical damping all decreased significantly (p < 0.01) with stor age time. There was no significant change (p > 0.05) in the damping co efficient of the fruit. The damping ratio decreased significantly (p < 0.01) with storage time. The models that described the changes in the se parameters with storage time were obtained by stepwise regression, and are also presented. It was concluded that a single degree-of-freed om model provides satisfactory results of the vibrational characterist ics of intact plantain fruit.