Abstract
The diversity of the user and use environment are increasing due to the rapid changes in popular taste and in the market which is caused by the internationalization recently. In artifacts design, therefore, we consider the qualitative factors such as user preference and usage. These qualitative factors could be discontinuity, so distribution pattern of fluctuation of functionality could become not normal distribution but nonnormal distribution. In this study, robustness of functionality was assumed as feasibility of which objective characteristic value is in tolerance. And, the way to calculate the robustness based on Monte Carlo method was proposed. We apply our proposal to the railway vehicle seat design and discuss the effectiveness of our proposal.
