This study proposes a methodology for designing boxes for agricultural products based on computational simulation and experimental validation, seeking the integrated optimization of geometric, structural and thermal aspects associated with cooling and refrigerated storage. The Finite Element Method was used for structural dimensioning and optimization. It was implemented using the ANSYS program, obtaining eight virtual models with 10% and 14% of effective opening area with square, rectangular or circular geometry. In order to develop the experiments that evaluated the relation between effective opening area and seven-eighths cooling time, the prototypes were built using reforestation wood (Pinnus elliotti). Approximately 13 kg of bananas (Musa cavendishii cultivar nanica) were packed in the boxes and cooled in a forced-air tunnel (air flow of 0.32 m³ s-1, temperature of 8.0±1.2ºC and relative humidity of 84.5±2.6%). Cooling time was also compared with the one obtained when the same amount of bananas was cooled in the boxes used to transport and store bananas commercially (cardboard box with 2% of effective opening area and a wooden box called " torito" with 18% of effective opening area). The results showed no significant differences in cooling time of bananas packed in boxes with circular, square and rectangular opening, with average cooling time of 40.71±2.81 min. However, when compared with cardboard and torito boxes, there was a significant difference in cooling time of 1.25 to 2 times the time obtained with wooden boxes. In the structural optimization of the EC-60 box (twelve 60 mm in diameter side orifices and 10% of effective opening area); material volume was reduced in 67.3% in relation to the project initial conditions. In compression tests, the box rupture occurred at loads between 5.4 kN and 8.1 kN, values 3 to 4 times heavier than the imposed project condition (2.0 kN). The computational simulation with optimization algorithms associated with cooling time experiments are promising resources to help in the box design for transporting products.
Musa Cavendishii; structural optimization; wood; cooling time; forced-air cooling; effective opening area; compression test
