MODELING THE VIBRATIONAL RESPONSE OF PLANTAIN FRUITS

摘要

Plantain fruits of the plantain subgroup (Musa AAB Group) were obtained at a green stage and used in this study. The fruits were labelled for identification, and stored in a chamber maintained at a temperature of 20C and relative humidity of 90 ± 4%. On daily basis, for a period of 14 days, the fruits were removed from the storage chamber and each was weighed to record the mass. They were vibrated vertically on a vibration exciter through a range of frequencies from 10 to 2000 Hz. The 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 storage time. There was no significant change (p > 0.05) in the damping coefficient of the fruit. The damping ratio decreased significantly (p < 0.01) with storage time. The models that described the changes in these parameters with storage time were obtained by stepwise regression, and are also presented. It was concluded that a single degree-of-freedom model provides satisfactory results of the vibrational characteristics of intact plantain fruit.