IMPACT AND BALLISTIC RESISTANCE OF A NEW ALUMINIUM ALLOY FOR SHIP CONSTRUCTION ELEMENTS

Abstract

The article presents results of examination of the new alloy 7020M intended to be used in shipbuilding. The examination concerned impact properties, verified on a numerical model, and the resistance to perforation (ballistic resistance). Impact and ballistic resistance tests aimed at increasing the operational safety of marine constructions to be made of this alloy under the threat of gunfire or explosion. Dynamic loading of the alloy 7020M leads to the increase of its strength, as compared to the static load, with the range of this increase depending on the strain rate. Splitting of the structure made of the alloy 7020M increases its impact resistance by three times when preserving the same thickness (g = 12 mm <=> g = 2x6 mm). The alloy examined in the structurally homogenous form revealed low resistance to perforation, while the use of 6 mm thick ballistic ceramic (Al₂O₃) fully protected this material against damage done by ŁPS 7,62 mm shells having the energy of 3 kJ. The split structure of the alloy ensured better protection against explosive pieces formed during 1,4 kg TNT explosion than the homogeneous structure having the same thickness.