The Effect of TNT Mass and Standoff Distance on the Response of Fully Clamped Circular Aluminum Plates to Confined Air-Blast Loading

Abstract

An experimental and numerical investigation was conducted to examine the response of fully clamped, 2-mm-thick, 255-mm-diameter, circular plates of Aluminum 2024-T3 to confined air-blast loading. The plates were subjected to pressure loading generated by detonating varying charge masses of trinitrotoluene (TNT) at several axial positions in the chamber. In the first set of experiments, the charge mass was varied from 14 g to 50 g and the charge was located at the center of the chamber. In the second set, all charges were 15 g in mass, but they were detonated at different standoff distances. The experimental parameters for the explosive charge mass and the standoff distance needed to produce initial cracks in the aluminum plates as well as the permanent deflections of the uncracked plates were determined. The tests were simulated using the Arbitrary Lagrangian-Eulerian capability in the LS-DYNA commercial finite element program. The numerical simulations generally produced a good match both to the onset of fracture and the permanent displacements in the test plates. The presence of afterburn was demonstrated in a separate test where no oxygen was present, and a better match of the permanent displacements produced by the smallest charges was obtained when afterburn was included in the simulation. The finite element mesh, analysis approach, and blast modeling methodology can be used as a design or evaluation tool for the analysis of potential blast events in full-scale aircraft.