Simple Tools for Simulating Structural Response to Underwater Explosions

Abstract

Today, many underwater explosion (UNDEX) shock problems are solved using direct transient analysis methods applied to detailed finite element models. Solution methodologies are diverse and complex, and necessarily include detailed representations of both the dynamic loading and the structure. As a result of these computational complexities, it is imperative that all such solution strategies also employ simple tools to benchmark and “ground” the more complex solutions. This paper illustrates the use of simple bounding solutions in generating reliable estimates of the global dynamic response of surface ship and submarine structures subjected to underwater shock. Three well documented methodologies are presented, including the Taylor flat plate analogy for both air- and water-backed plates, the peak translational velocity (PTV) method, and the application of the conservation of momentum principle to estimating the vertical kickoff velocity of floating structures (spar buoy approach). Derivations of the governing equations associated with each of these solution strategies are presented, along with a description of the appropriate ranges of applicability. Finally, practical applications of these “bounding” methods are summarized.