A Comparative Analysis of Air-inflated and Foam Seat Cushions for Truck Seats 2002-01-3108
A comprehensive comparison between an air-inflated seat cushion designed for truck seats and a commonly used foam cushion is provided, using a single-axis test rig designed for seat dynamic testing. Different types of tests were conducted in order to evaluate various aspects of each type of cushion; in terms of their response to narrowband (single frequency) dynamics, broadband input of the type that is commonly used in the trucking industry for testing seats, and a step input for assessing the damping characteristics of each cushion. The tests were conducted over a twelve-hour period—in four-hour intervals—measuring the changes that occur at the seat cushion over time and assessing how these changes can affect the metrics that are used for evaluating the cushions. The tests indicated a greater stiffening of the foam cushion over time, as compared with the air-inflated cushion that showed almost no change in stiffness when exposed to a static weight for twelve hours. Furthermore, pressure measurements at the seat showed higher-pressure concentrations for the foam cushion at the bony prominence of the seat profile—namely, the ischial tuberosities—as compared to the air-inflated cushion. A series of tests aimed at evaluating the damping properties of each cushion showed both cushions to have nearly identical damping properties. Other methods used for evaluating the dynamic properties of the two seat cushions included those recommended by studies in the past, as well as new techniques that were developed specifically for this study. The results show that the air-inflated seat cushion can provide significant improvements in pressure distribution between the seat cushion and the driver, therefore providing a more comfortable ride and possibly causing less fatigue.