A Study on Dynamic Behavior of Offshore Structures Under the Blast Load

Safety verification against blast load is important in offshore structure for oil and gas development which have the high possibility of explosion accident. The structural response against blast is a nonlinear dynamic phenomenon, it is necessary the nonlinear dynamic analysis for accurate structural behavior. But it requires much more computing resource and manpower than conventional linear analysis. Therefore, simple approaches such as modified code check and Biggs’ simplified SDOF have been widely used for the structural verification. These approaches are very useful in design for simplicity and conservativeness. However, they don’t represent proper dynamic characteristics, thus sometimes they may cause excessively conservative. In this paper, the dynamic characteristic of structures beyond the yield point is studied by using nonlinear dynamic FE analysis and more safe and economic approach is suggested.