Assessment of Memory Cushions in Aircraft Seating for Injury Mitigation through Dynamic Impact Test.

Dynamic impact tests with a FAA Hybrid III 50th percentile crash dummy in seats with and without a stroking energyabsorbing mechanism were conducted to assess the effectiveness of memory foam cushions in mitigating impact to the occupant during an aircraft crash. Polyurethane foam (PU) cushions were also tested for comparison. The results obtained when using a rigid seat indicated that for an 8.3-m/s impact, lumbar spinal injury would occur. Memory cushions could reduce lumbar force by up to 34%. For an impact speed of 6 m/s, a memory cushion could mitigate the impact to a tolerable level, while the injury would still occur with the PU cushions. The results with the energy-absorbing seats showed that for an 8.3-m/s impact speed, the seat with over 125 mm (5 inches) stroking length is able to prevent injury. Relatively softer memory cushions reduced lumbar force by over 15% compared with the PU cushions. With a stoke length of 75 mm (3 inches), bottom-out occurred and occupant lumbar spinal injury would occur. Relatively higher stiffness memory cushions reduced lumbar force by approximately 20%. [ABSTRACT FROM AUTHOR]