Comfort Evaluation of Slow-Recovery Ejection Seat Cushions Based on Sitting Pressure Distribution

Abstract

Sitting discomfort not only affects the health of pilots carrying out long-endurance missions but also affects operational performance. The experimental objects included four ejection seat cushions: N1 was a fast-recovery foam as the comparison group, and the experimental groups were slow-recovery foams with different indentation force deflection (IFD), named N2 (hard), N3 (mid), and N4 (soft). The sitting comfort of 20 participants was tested on the four cushions by using subjective rating and sitting pressure distribution analysis. The results showed that compared with fast-recovery cushion N3 and N4 slow-recovery cushions have lower contact pressure and more uniform pressure distribution. Slow-recovery cushions that were too soft or too hard would reduce the comfort. No matter from the subjective rating or the analysis of the contact pressure data, the N3 cushion with a thickness of 3 cm and 65% IFD of 280 N had the highest comfort. In addition, the seat pressure distribution (SPD%) has a significant correlation with the subjective rating (p = 0.019, R = −0.98), which is more suitable for evaluating the comfort of the cushions. However, the slow-recovery cushions would show a decrease in support after a period of sitting, while the fast-recovery cushion could always maintain constant support.

Sitting Comfort in an Aircraft Seat with Different Seat Inclination Angles

“…Although the contact area was larger when the inclination angle increased, the fixed angle led to a non-uniform distributions of the force, where pressures were concentrated at the buttock and the shoulder areas. This might be the reason of the lowered comfort score in the 18-degree setting (Bao et al, 2021). Meanwhile, the position of the gravitational center was moved towards the posterior direction with the increases of the angles, this might restrict movement as well (Kim et al, 2014).…”

Preparation and Evaluation of an Elastic Cushion with Waste Bamboo Fiber Based on Sitting Pressure Distribution of the Human Body

“…It is difficult for users to evaluate the structure and parameters of a cushion, but easy to give clear feedback on the comfort of body parts [24,26]. Therefore, the subjective evaluation of BEC comfort was focused on the comfort rating of some key body parts, including buttocks, sciatic nodes, thighs, and thigh roots.…”

“…Tang et al [23] used the sitting pressure distribution as an indicator to design the distribution of foams in the cushion, and found that the cushion with a bulging front had a more uniform pressure distribution. Bao et al [24] tested the sitting comfort of four cushions by using subjective rating and sitting pressure distribution analysis and showed that the slow-recovery cushions that were too soft or too hard would reduce the comfort. Carrigan et al [25] developed a cushion system based on the sensor air unit and showed that adjusting the pressure of inflating cushion units with pressure mapping could obtain a uniform pressure distribution.…”

Influences of cushion contour on passenger comfort and interface pressure in high-speed train

“…Akgunduz et al [ 15 ] found that the relationship between contact area, contact force, and peak pressure is also directly related to the anthropometry and the cushion’s ability to deform under the weight of the subject. In fact, the effect of human-chair contact pressure and deformation is closely related to the cushion hardness and material [ 16 , 17 ], but also to the sitting depth [ 18 ] and the footrest height. For aged care seating, armrests were essential for ease of entry and egress [ 19 ].…”