Mechanical behaviour of saturated wood under compression .1. Behaviour of wood at high rates of strain

The mechanical behaviour of three species of hardwoods soaked in different swelling liquids, compressed at high rates of strain, was investigated using a split Hopkinson pressure bar system, Variations in elastic moduli, proportional limit and maximum stress with respect to the treatments were studied. It was found that the saturated specimens could be as stiff as the dry ones. This result was explained by the behaviour of the liquid present in the large cavities of the wood, i.e. the lumens of the cells, which must be different from that observed at low rates of strain. At large rates of strain, this liquid cannot flow out of the pores and must behave like a solid; therefore the structure of the material is reinforced and, as a consequence, the softening effect of the soaking agent can be masked.