Statistical Analysis of the Stress-Energy Methodology Applied to Cushion Curve Determination

Abstract

Abstract The stress-energy method is a proposed alternative to ASTM D1596 that reduces all drop height, thickness, and static load combinations into a single equation that can be used to generate any reasonable cushion curve for a particular material. There remains a question as to how accurately the stress-energy method can predict deceleration values and whether it is statistically comparable to the method described in ASTM D1596. There are three phases to this research that attempt to determine the accuracy of the stress-energy method: gathering data using the stress-energy method and analyzing the goodness of fit of the stress-energy equation, predicting a cushion curve and observing the upper and lower bounds for a given drop height and thickness, and using ASTM D1596 to create a cushion curve with the same drop height and thickness and comparing it to the predicted cushion curve. Analyzing ten stress-energy data sets using the root mean square error in addition to the coefficient of determination provided a more thorough goodness of fit analysis. Utilizing the stress-energy method to predict cushion curves produced minimal errors and similar decelerations when compared to six actual cushion curve data sets.