Effects of pendulum tuned mass dampers on the dynamic response of jacket platforms

Abstract

We investigate effects of pendulum tuned mass damper (PTMD) configuration as well as structural excitation frequency by ocean waves on the dynamic response of a jacket platform. To do this, an offshore jacket platform equipped with a PTMD with different values of frequency ratio (β), damping ratio (ξd) and mass ratio (m‾) is numerically simulated in ANSYS software under the action of irregular waves with different values of structural excitation frequency ratio (α). The results of the numerical simulations are validated against the experimental and numerical data available in the literature. The validations were in complete agreement with the benchmarking data. The results suggest that with a constant β, an increase in ξd of about 20 times reduces the standard deviation of the deck displacements (σ) tblf about 7.41%. Further, with an increase in β, σ increases when β>1 and decreases when β≤1. Regarding the pendulum mass ratio, an increase in m‾ of about 14 times results in a 12.91% reduction in σ within the range of ξd≤0.15. Out of the latter range (i.e. for ξd>0.15), σ is not significantly affected by m‾. Considering σ as the fitness function, the most optimal configuration for the PTMD system is achieved for α=1.2, β=1 and ξd=0.2.