Enhanced dissipation of a jacket platform provided by a steel brace containing a multistable bilayered column

Abstract

Wave-induced impacts on jacket platforms generate strong vibrations in a low-damping metal structure, which causes severe damage. To resist impact and suppress vibration, a type of steel brace containing a multistable bilayered (MSB) soft material/steel column that provides a flexible combination of high stiffness and enhanced damping is designed according to the structural composite and stability mechanism. Finite element modeling (FEM) simulations show that the dissipated power of the MSB column is several times of magnitude higher than that of an existing multistable steel column (Wang et al., 2019) under cyclic loading, whereas the initial stiffness is similar to that of the steel column. Through a combination of hybrid lamination and mixed boundary theoretical methods, the multistable transformation of the MSB column is analyzed, which indicates that the soft layer manipulates the neutral axis of bending deformation and highly enhances the damping efficiency. Parametric studies conducted on the lamination properties illustrate the stiffness and damping configurations of the MSB module. In FEM simulations under impact loading, a representative jacket platform embedded with dissipative braces containing MSB columns exhibits a substantial increase (eightfold increase in magnitude) in the decay coefficients of the system compared to those of the platform embedded with braces containing existing steel columns. The simulation results demonstrate the potential of the multistable composite member to obtain high stiffness and enhanced damping in marine structures.