Response of Compliant Tower under varying Characteristics

An Articulated tower is an upright tower, which is hinged at its base with a universal joint and is free to oscillate about this joint due to the environment. The base below the universal joint on the sea bed may be a gravity base or may be piled. The tower is ballasted near the universal joint and has large enough buoyancy chambers near the free surface to provide large restoring moment. In this paper, dynamic analysis of the double hinged articulated tower under random waves for three different Articulated Tower models has been carried out with current force. Lagrangian approach has been used for the solution of nonlinear governing equations of motion. Nonlinear effects due to variable submergence, buoyancy, added mass, instantaneous position of the tower and relative-velocity squared drag force are considered in the analysis. The equation of motion has been solved in time domain using Houbolt integration technique. The wave forces have been computed as per the Stokes' fifth order nonlinear wave theory and hydrodynamic forces has been calculated as per modified Morison's equation with Chakrabarti's modifications. The study shows that response parameters get decreased with the increase in structural mass of tower. The study further shows that due to increase in the deck mass, the base and upper hinge shear get increased while other response parameters get decreased.