Numerical analysis of offshore topside with FGM under impact loads

Impact loads due to the fall of objects always challenge the integrity and strength of the structural components. The deck of an offshore platform's topside is prone to impact loads during its construction and operation stages. Fall of objects from a considerable height may damage the structural components and lead to excessive deformation of the deck, which affects the platform operations and results in losses of lives. Impact loads generally arise from the fall of crane hooks, machinery, drill pipes, equipment, and tools. Severe impact load on deck may damage stiffeners, secondary beams, the collapse of the deck, etc. The topside deck and supporting structural components should possess adequate energy absorption. Functionally graded materials (FGMs) possess improved resistance to second-order vibrations, buckling, bending, high pressure, and temperature. FGM as a structural element in offshore platform applications is scarce in the literature. In the present study, FGMs are used to model the deck and stiffeners to improve energy absorption compared with X52 steel and aluminium. The focus is on providing more suitable material for the topside deck and improving its impact resistance without increasing its thickness. A typical offshore crane hook is falling from 20 m height considered for the analysis. Functionally graded materials showed improved energy absorption, reduced plastic strain, and deflection due to the material's enhanced mechanical properties. The response of the deck is determined by ABAQUS explicit.