Experimental investigation on the damage effect of 6063-T5 aluminum alloy circular tubes subjected to blast after exposure to fire

摘要

There is a potential risk that the metal tube structures would suffer the combined actions of external fire loads and blast loads during their service life. In this study, the damage effects of 6063-T5 aluminum alloy circular tubes with different wall thicknesses subjected to blast after exposure to natural fire were experimentally investigated. With a special experimental device platform designed, the explosive loading in a very short interval after fire was realized. The deformation and damage of the circular tubes were quantified, and the characteristics of four failure modes were analyzed. The effects of fire duration, stand-off distance and wall thickness on the deformation and damage of circular tubes were quantitatively studied by introducing energy ratio and flattening parameter. The results show that the increase of fire duration and the decrease of stand-off distance or wall thickness could obviously aggravate the damage degree of the circular tube, while the energy absorbed by plastic deformation area and flattening parameter basically increase. By using surface fitting, the functional relation of the temperature and the scaled distance to the global deflection of the tube was obtained. In addition, the variation trend of the deformation parameters was constant in the case of no fracture. Once the fracture occurs, the variation trend of some deformation parameters would be affected.