Numerical simulation of concrete-filled double skin steel tubular (CFDST) structure subjected to underwater explosion loading in Abaqus

Numerical simulation of concrete-filled double skin steel tubular (CFDST) structure subjected to underwater explosion loading in Abaqus has been don in this example. The concrete column is modeled as a three-dimensional solid part. The inner and outer steel tubes are modeled as shell parts. The air, water, and TNT are modeled as three-dimensional Eulerian parts. You can see a figure of the assembled parts below

Underwater explosions (UNDEX) have been becoming one of the primary threats to the safety of marine and offshore structures. Thus, the underwater blast resistance of marine and offshore structures has become an important defensive and anti-terrorism capability around the world. It is increasingly important to investigate the structural behavior of components subjected to UNDEX loading. The methodology for investigating UNDEX includes experiment and numerical modeling. Compared with the UNDEX field test, where time and commercial consumption is generally huge, finite element analysis (FEA), where suitable, becomes preferred due to its high efficiency and comprehensive parameter range. Hence, the present paper adopts the FEA method to investigate the UNDEX of structures. structures. Concrete-filled double skin steel tube (CFDST) is a structure composed of an inner tube and an outer tube and has sandwiched concrete filled in between. The CFDST is more and more introduced into offshore structures, such as submarine pipeline

To model concrete behavior under severe load, the Concrete Damaged Plasticity with Strain damage capability is selected. The Johnson-Cook damage and hardening is so appropriate for the steel tubes under high strain rate. The JWL equation of state to define TNT or explosive material is considered. The Us-Up equation for water and Ideal gas for air is selected

Dynamic explicit step is a proper approach to analysis the under water explosion. All contact is the domain are considered with a contact property. The proper mechanical and Eulerian boundary condition are assigned to the parts. The mesh should be fine to obtain correct results

After the simulation, all results such as stress, strain, failure, damage, explosion waves, blast wave velocity, and others are available. You can see some figures for the results below