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A. M. Segal, l. McKenzie, L. Neil, M. Rees


A dynamic test was carried out on domestic seating foam and on two types of highly damped seating foams. The test was carried out at 17 G and 9.4 m/s, using three Hybrid III mannequins - 5th percentile female, 50th percentile male, and 95th percentile male. Using 'Dlrnafoam' (called 'Sunmate' in the U.S.A.), there was a significant logarithmic relationship between foam thickness and reduction in lumbar spinal load. The foam absorbed significant energy even after four years intensive use in glider seating. Cold foam absorbed impact energy, but this portion of the test has to be considered unreliable. Another foam, 'Plastazote', was tested briefly and also showed reduction in spinal load. However, it showed continued deformation for some time after the test impact. The domestic seating foam showed a slight reduction or no change in spinal load - previous tests have always shown an increase in spinal load. The lumbar spinal load in the 95th percentile male was less than the load in the 50th percentile male mannequin; this finding requires a logical explanation.


Structures, Materials, Design, Safety

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