Ground Surface Shock Absorbency.
Research study rept.,
QUARTERMASTER RESEARCH AND ENGINEERING CENTER NATICK MA
Pagination or Media Count:
Shock absorbency of various types of ground was tested by dropping impactographs from different heights on a 16-foot drop tower. Results showed that water ahs the greatest shock absorbency of all of the surface materials incuded in this study. However, the problems connected with recovery, and possible damage to items by water itself seriously lessen its value as a drop surface in air drop oeprations. Shallow water tends to reflect the shock absorbency characteristics of its underlying materials. The shock absorbency of a partially compacted sand surface was demonstrated to be approximately 35 less than that of loose dry sand. Moisture in loose sand tends to lessen its shock asborbency by 5g to 40g, depending on the amount present. Dry clay dust is a slightly better shock absorber than loose dry sand. However, deceleration values obtained on compacted dry clay were exceeded only by those on concrete and rock. Both moist dune sand and wet beach sand surfaces have nearly four times greater shock absorbency than concrete or rock surfaces.