Dynamic response of offshore jacket platform including foundation degradation under cyclic loadings

Study on a magnetorheological elastomer-base device for offshore platform vibration control

“…A FE analysis is conducted to study the vibration characteristics of the offshore platform, which provides a practical and less expensive way for studying the free-vibration and dynamic responses of offshore structures (Mao et al, 2015; Raheem, 2016). The focus of the present work is vibration control of jacket structure, and hence, the superstructure above the jacket structure is denoted by a lumped mass (Asgarian et al, 2004).…”

“…In Figure 9, it is seen that the maximum displacement of offshore platform under wave-induced loadings is 0.339 m; the maximum displacement occurs at the top of structure due to the boundary condition of jacket offshore platform in bottom. The maximum displacement is located on the deck since the boundary and loading conditions of jacket offshore platform, that is, in practical, the bottom of jacket offshore platform is constrained and wave loadings are applied in sea level, and hence, the total jacket offshore platform can be simplified as a cantilever beam with loadings applying in the middle span (Mao et al, 2015), which indicates that the maximum displacement is located in the top as shown in Figure 10.…”

“…For exploration and production of oil and gas, the offshore structure industry has been flourishing since early 1940s (Mao et al, 2015). One of the most typical offshore platforms is fixed steel jacket platforms located in water depth from a few meters to more than 300 m (Ou et al, 2007).…”

“…Different from controllable-damping MRF devices, MRE devices with controllable stiffness may provide rebound elastic force, which is in direct proportion to amplitude and stiffness (Li et al, 2012). It may be more suitable to control wide-band low-frequency vibration (Li et al, 2012), just like wave-induced vibration (Mao et al, 2015). In addition, in a review of vibration control methods for marine offshore structures (Kandasamy et al, 2016), it is suggested that MRE-base device may provide a prominent performance for vibration minimization.…”

Frequency Domain Response of Jacket Platforms under Random Wave Loads

“…The response of offshore platforms with hydrodynamic buoyant mass dampers to wave loads, which leverage on the buoyancy and inertia of the dampers for the hydrodynamic damping effects that reduce the displacement response of the platform, was investigated by Moharrami and Tootkaboni [10]. Mao et al [11] studied the dynamic responses of offshore jacket platforms, including foundation degradation under cyclic loadings where finite element models using the lumped parameter method were established to handle pile-soil interaction. Abhinav and Saha [12] performed coupled hydrodynamic and geotechnical analyses of an offshore jacket wind turbine by considering it both with and without soil-structure interaction.…”