Behaviour of a package dropped onto yielding and unyielding targets

IAEA transport regulations require the 9 m drop test for type B packages. The target used in this drop test must be unyielding. However, the real target that a transport package might encounter at an accident during transport is a yielding target, such as concrete, asphalt, or soil. To compare the impact acceleration between a real target and an unyielding target, analyses of the drop test onto a real target and an unyielding target were performed by using a LS-DYNA-3D computer code. A road surface is usually concrete or asphalt, and such surfaces are very hard; but there are soil, sand, etc. under these materials, so the impact caused by a drop accident is relatively small. It becomes clear that the drop height onto a road, corresponding to the 9 m drop height required by IAEA regulations is about 50 m, and the impact velocity is about 110 km.s-1. (Author)