Seat Comfort as a Function of Occupant Characteristics and Pressure Measurements at the Occupant-Seat Interface

Seat comfort is a highly subjective attribute and depends on a wide range of factors, but the successful prediction of seat comfort from a group of relevant variables can hold the promise of eliminating the need for time-consuming subjective evaluations during the early stages of seat cushion selection and development. This research presents the subjective seat comfort data of a group of 30 participants using a controlled range of seat foam samples, and attempts to correlate this attribute with a) the anthropometric and demographic characteristics of the participants, b) the objective pressure distribution at the body-seat interface and c) properties of the various foam samples that were used for the test. It was found that: a) the “Indentation Load Deflection” characteristic (or ILD) of the foam was a very significant factor (within the scope of this experiment) contributing to subjective comfort, b) the age of the participants had an effect on comfort ratings as well as the seating pressure variables and it also interacted with seat ILD in influencing the seat comfort ratings, c) the anthropometric measures were not found to be significant factors during this experiment; however, subject weight, standing height and buttock-to-popliteal length contributed in predicting average and maximum pressures on the seat cushion as well as the seat back, d) the repetition of measurements did not have a significant effect on inducing variability in the data, e) the seat back pressure data showed a significant influence over both the seat back comfort and the overall seat comfort, f) several correlations supported the relationship between an evenly distributed pressure distribution (without significant and elevated peaks) and improved subjective comfort rating.