On momentum transfer and external work done to clamped elasto-plastic beams in an air blast

This paper revisits a classical fluid-structure interaction problem on the momentum transfer and external work done to structures by a blast wave propagating in a nonlinear compressible medium (air). A fully-clamped ductile beam system is considered here, in place of the rigid free-standing plate used in the KNR theory (Kambouchev et al., 2006 [2], 2007 [3]), which takes into account limits to material deformation, boundary compliance and boundary failure. The model is used to critically re-evaluate the impulse imparted to the beam, and the subsequent external work done by a blast wave, for different modes of the beam deformation compared to its free-standing counterpart of identical mass per unit area (considered previously by others). It will be shown that the maximum beam deflection, transmitted impulse and external work done by the interface pressure are insensitive to FSI effects if loading is sufficient severe to induce boundary failure. Comparisons are also made between the structural performance of the beam system during fluid structure interaction in a compressible and incompressible fluid medium.