This paper presents a methodology to assess both the pressure impulse from a gas explosion in a semiconfined structure and the subsequent response of the structure to the imposed loads.
Analytic fluid dynamic explosion modeling methods for semiconfined structures are described. An iterative approach to developing the pressure impulse for the structure is presented. The method uses a series of intermediate structural response and explosion simulations to produce a pressure impulse which is characteristic of the explosion scenario examined.
The structural response analysis emphasizes estimating maximum response, permanent deformations, and post-explosion stability. An elasto-plastic model is used in the structural analysis to account for nonlinear structural behavior and dynamic response. It considers strain rate effects and statistical bias between minimum and actual yield stress values.
The method provides engineers with a tool which, if used in the design or refurbishment of topsides, can significantly enhance their blast resistance characteristics.