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Long periods of sitting occur during our day to day life. It has been estimated that up to 80% of our active non-sleeping time is spent in some sort of sitting position during work, recreation, entertainment, commuting, resting, and exercising. As a result, several health effects like numbness, nerve/circulation occlusions, pressure sore, low back pain, and vein thrombosis have been associated with protracted sitting. Numerous researches have been conducted in the area of seat comfort that depended on conventional methods of testing physical prototype of seat model for comfort. The implementation of the seat comfort results are implemented in the next cycle of the design which may take up to three years. Recent advances in new technology, available after the prototype seat comfort testing, may not be incorporated in the next new seat design. This research work is geared towards developing a technique, tool and metric for seat comfort prediction.

Traditionally, seat comfort analyses are performed on physically produced seats and, in most cases, human subjects are asked to sit for a period of time to obtain personal subjective and objective comfort measurements. When performed in the seat comfort research laboratory at Tennessee State University, such procedures required close to 900 hours of testing to achieve feasible results. Besides, the costs of the procedures were noticeably high. One of the studies performed in the Lab employs computer driven techniques to avoid physical prototyping for seat comfort analyses. This technique is sought to eliminate the dependence on the traditional techniques and reduce resources consumptions. This study presents the crucial procedures needed to validate and authenticate the new technique by comparing its outcomes to those obtained by the traditionally established techniques.

This paper presents a PC based mathematical and rapid prototyping technique for anthropometric accommodation in a maintenance environment using the principle of simulation based design. The developed technique is capable of analyzing anthropometric data using multivariate (Principal component Analysis) approach to describe the body size variability of any given population. A number of body size representative cases are established which, when used properly within the constraints of the maintenance environments, will ensure the accommodation of a desired percentage of a population. This technique evaluates the percentage accommodation of a given population for the environment using the specific manikin cases as boundary conditions. In the case where any member of a maintenance crew cannot be accommodated, the technique has the capability of informing the designer of the environment why the member(s) is/are not accommodated.

Jet fighter missions have been known to last extended period of time. The need for a comfortable and safe seat has become paramount considering that fact that uncomfortable seats can lead to numerous health issues. Several health effects like numbness, pressure sore, low back pain, and vein thrombosis have been associated with protracted sitting. The cushion, and of late the installation rail angle are the only components of the ejection seat system that can be modified to reduce these adverse effects. A comprehensive static comfort evaluation study for ejection seats was conducted. It provides comparison between a variety of operational and prototype cushions (baseline cushion, honeycomb and air-cushion) and three different installation rail angles (14°, 18°, and 22°). Three operational cockpit environment mockups with adjustable installation rail angle were built. Ten volunteer subjects, six females and four males, ages 19 to 35, participated in the seat comfort evaluation.