2015 : A study of the dynamic longitudinal hull structural responses and ultimate strength of drillship

Prof. Ir. Eko Budi Djatmiko M.Sc Ph.D


Abstract

Sustainability studies will support the development of drillship design. One primary aspect to be explored during the design stageis the global structural responses due to the excitation of head sea waves. This paper presents the global structural response analysis by implementing the so called quasi-static approach and the effect for ultimate strength. In this respect, a motion analysis should be first carried out to obtain the coupled heave and pitch motion data for a range of regular wave frequency. The next step is performing the quasi-static computation for a number of wave frequencies, where the magnitudes of heave and pitch motions are considered important. After accomplishing RAO of shear force and bending moment calculation, further analysis is obtained the extreme global structural responses by implementing the spectral approach. It will be inputed to Global Finite Element Model (FEM) to get the ultimate condition of drillship material. Final results of the global analysis indicates the ultimate condition is exceeded on 12 meter wave height by the Structural Stress output of 585 Mpa.