Comparative Blast Performance of Arched and Three-Layer Space-Frame Shields for Offshore Platforms

Accidental gas explosions on fixed offshore jacket platforms can impose short-duration, high-intensity loads on safety-critical topside and primary structural components. This study evaluates two lightweight blast-shield concepts intended to reduce structural demand: a convex arched double-layer space frame that promotes shock-wave deflection and a flat three-layer space frame that increases out-of-plane stiffness and member stability. Three shield configurations were generated using formex-based topology processing and analyzed in Abaqus/Explicit under a standardized ۲۰۰۰ kg TNT-equivalent airblast at an ۸.۰ m stand-off distance scaled distance  = ۰.۶۳ m/kg۱/۳. Relative to the flat double-layer baseline, the arched shield reduced internal strain energy by approximately ۲۵% (from ۷۲۱۵ to ۵۴۰۰ kJ), peak transmitted base shear by approximately ۲۳% (from ۱۱۰۰ to ۸۵۰ kN), and maximum central displacement by approximately ۳۰% (from ۲.۳۳ to ۱.۶۲ m). The three-layer configuration provided the greatest deformation control, reducing the maximum central displacement by approximately ۵۱% to ۱.۱۵ m, while its additional structural depth improved member-stability potential. The three-layer configuration limited the maximum central displacement to ۱.۱۵ m compared with ۲.۳۳ m for the baseline and reduced the characteristic unbraced length of the internal diagonal members, thereby improving their member-stability potential. The results indicate that curvature is effective when weight and force transmission govern design, whereas the three-layer topology is preferable when displacement and local stability are controlling criteria. These findings are specific to the modeled geometry, material assumptions, and blast scenario and should be validated experimentally before design application. These results demonstrate a criterion-dependent trade-off: the arched configuration is advantageous when reduced structural demand and support-force transmission are prioritized, whereas the three-layer configuration is preferable when deformation control and member stability govern. The findings are scenario-specific and should be interpreted within the limitations of the adopted CONWEP-based numerical framework.

کلیدواژه ها:

Offshore platforms ، Blast mitigation ، Shock-wave deflection ، Arched space frames ، Space-frame blast shields ، Abaqus/Explicit