Dilatation and Separation Mechanism of Fast-growing Poplar by Explosive Loading

摘要

The dynamic mechanical properties of dry and saturated fast-growing poplar under the compressive loading at higher strain rate has been investigated by split Hopkinson pressure bar (SHPB) and compared with the ones of quasi-static compression experiment to analyse and create the separation mechanism of saturated fast-growing poplar by explosive loading in the paper. The results show the compressive stress-strain curves of poplar have the "three regions" character, namely elastic region, collapse region and densification region. The dry poplar samples are densified for the collapse of cell walls, oppositely the saturated ones are detached along the grain direction. Dilatation and separation mechanism of fast-growing poplar by explosive loading is attribute to water in the cellular tubes which can't be compressed and extruded from fiber at higher strain rate. Thus, fiber bundles are separated and dilated along the axial direction by tensile derived from water and reflection in the free terminal under compressive stress.