The response of a simple welded structure under dynamic loading conditions

Abstract
The ability of simple structures to absorb impact energy has a number of applications particularly in mitigation systems. This paper describes integrated modelling and experimental work to characterise the impact response of simple aluminium spheres when empty and filled with water. The experimental work identified the deformation modes and their relationship to impact velocity over a range of velocities up to 200 m.s^-1 and included studies of the impact of a single sphere against a rigid surface and the impact of a sphere on another sphere. The numerical modelling showed the importance of friction between the sphere and the impacting surfaces and the weld in controlling the deformation and failure modes. The weld controlled the onset and development of failure. The validation of the modelling studies in predicting the deformation response of the spheres allowed the construction of an iso-damage relationship to predict their response over a wide range of impact conditions. The inclusion of the water as a fill material provided a scaled impact vehicle to study hydraulic ram and the response of a range of fluid filled containers. This has particular relevance to pressure vessels containing volatile explosive liquids and gases.