The applicability of the various hydrocode methodologies (Lagrangian, Eulerian, Coupled Eulerian–Lagrangian, and Arbitrary Lagrangian–Eulerian) for structural response to underwater explosions is reviewed. Only codes employing “structural elements” are realistically applicable to the analysis of thin-walled structural response to underwater explosions.

The evolution of the 1D explosion bubble flow field out to the first bubble minimum is examined in detail using four different models. The most detailed is based on the Euler equations and accounts for the internal bubble fluid motion, while the simplest links a potential water solution to a stationary, Isentropic bubble model. Comparison of the different models with experimental data provides insight into the influence of compressibility and internal bubble dynamics on the behavior of the explosion bubble.

Benchmarks for submerged structure response to underwater explosions (UNDEX) are compiled. Both analytical and empirical benchmarks are presented; each type has advantages and disadvantages for the purposes of model validation, though no methodology for employing these benchmarks in a model validation effort is proposed. Benchmark computations are also referenced as part of this compilation. Finally, extension of this compilation to the UNDEX response of internal equipment and floating structures, and to hydrodynamic/hydraulic ram problems, is proposed.

A detailed solution to the transient interaction of plane acoustic waves with a spherical elastic shell was obtained more than a quarter of a century ago based on the classical separation of variables, series expansion, and Laplace transform techniques. An eight-term summation of the time history series was sufficient for the convergence of the shell deflection and strain, and to a lesser degree, the shell velocity. Since then, the results have been used routinely for validation of solution techniques and computer methods for the evaluation of underwater explosion response of submerged structures. By utilizing modern algorithms and exploiting recent advances of computer capacities and floating point mathematics, sufficient terms of the inverse Laplace transform series solution can now be accurately computed. Together with the application of the Cesaro summation using up to 70 terms of the series, two primary deficiencies of the previous solution are now remedied: meaningful time histories of higher time derivative data such as acceleration and pressure are now generated using a sufficient number of terms in the series; and uniform convergence around the discontinuous step wave front is now obtained, completely eradicating spurious oscillations due to the Gibbs' phenomenon. New results of time histories of response items of interest are presented.

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