Abstract
Aluminum beverage bottles with a screw top of 28-mm and 38-mm in diameter have been launched on to the Japanese market recent years to meet new drinking custom trend of the consumers. However, some Japanese customers feel that the 28-mm opening is too small and also feel that the 38-mm opening is too large. Therefore, we need to develop a method to evaluate human feelings when drinking directly from the bottle opening and to identify the opening size that is best for consumers' drinking ease. Hence; we propose an evaluation function of drinking ease in order to identify the rigorous dimension of opening diameter. We defined the evaluation function of drinking ease in terms of difference between the actual flow amount from the bottles and the appropriate flow amount. If the difference decreases, the consumers possibly feel comfortable. We considered three variables (the bottle opening size, the remaining beverage amount in the bottles, and the height of subjects) and constructed the evaluation function of drinking ease using Radial Basis Function Network. Results from the optimization of the proposed function, the subjects may get the closest beverage amount to the appropriate amount and feel comfortable when they drink from the 34.3-mm opening. We have identified the rigorous dimension of opening diameter that the subjects may feel comfortable using the proposed function.
