SHIP STRUCTURES SUBJECT TO HIGH EXPLOSIVE DETONATION

Predicting the structural response of a naval vessel to a high explosive detonation is an important requirement in naval shipbuilding. Unfortunately, current analysis methods do not provide high level of confidence leading to the utilization of large structural design safety factors. As a result, ships are heavier and more expensive to construct and maintain than may actually be required. Moreover, more reliable predictions can support innovative structural configurations, which provide lower life-cycle costs with increased survivability. In the currently used approaches, pressure-time history is initially generated from empirical equations and/or test data, and then the time dependent pressure is applied to the structure. These approaches have many limitations and use various approximations. This paper highlights a numerical simulation procedure for the prediction of the effect of the detonation of high explosive compounds on steel structure. The dynamic simulation interfaces the blast wave predicted by the Jones-Wilkins-Lee (JWL) equation of state for high explosives (built-in the LS-DYNA equation of state library), with time dependent spatial response of the structure. The air surrounding the structure is modeled to represent the medium in which the blast propagates using the LS-DYNA multi-material elements. A linear polynomial equation of state is used to simulate the proper behavior of air. Several explosion tests with different configurations (internal and external) were conducted in order to quantify the effect of a detonation on different structurally representative test articles. It was established that the numerical simulation demonstrates good correlation with the empirical results.