There are some disadvantages for existing heave compensation systems of drill string used for the Floating Drilling Platform (FDP), including high energy consumption, large and complex structure, and expensive manufacturing and maintenance costs. In view of the above, we present a streamlined mechanical semi-active heave compensation system (MSAHC) in this study. This system consists of active ...

Tuna are fast, economical swimmers in part due to their stiff, high aspect ratio caudal fins and streamlined bodies. Previous studies using passive caudal fin models have suggested that while high aspect ratio tail shapes such as a tuna's generally perform well, tail performance cannot be determined from shape alone. In this study, we analyzed the swimming performance of tuna-tail-shaped hydrof...

In this paper, we present a fully coupled computational fluid dynamic (CFD) and discrete module beam (DMB) method for the numerical prediction of nonlinear hydroelastic responses ship advancing in regular focused wave conditions. A two-way data communication scheme is applied between two solvers, whereby external pressure exported from CFD simulation used to derive structural DMB solver, deform...

Results are presented of a benchmark study organised by the ISSC-ITTC Joint Committee on global linear wave loads container ship with forward speed. The aim is assessment uncertainty in transfer functions due to different seakeeping codes and consequences long-term extreme vertical bending moments. Seven institutes participated benchmark, fifteen codes, representative theories use nowadays. Thr...

At present, dry wellheads are usually adopted on small-storage TLP and SPAR platforms to develop offshore oil gas because of the robust hydrodynamic performance under severe-wind seas. On other hand, FPSO FDPSO that have a larger storage capacity can hardly use this cost-saving facility due their relatively poor vertical motion performance. Cylindrical FPSOs proposed improve heave ship-type FPS...

Accurate modelling and simulation of ship motion in seaway is essential to test applications of ship motion control strategies. In this report, we review the mathematical description of ocean waves, and their effect on the motion of marine vehicles. We present a simple method suitable for accurate simulation that incorporates parameters related to the recommended spectral family and particular ...

Serious floor heave in gob-side entry retaining (GER) with fully-mechanized gangue backfilling mining affects the transportation and ventilation safety of the mine. A theoretical mechanical model for the floor of gob-backfilled GER was established. The effects of the mechanical properties of floor strata, the granular compaction of backfilling area (BFA), the vertical support of roadside suppor...

In order to perform multi-degree-of-freedom motion measurements of marine machinery, such as ship-borne mechanical platforms, in an absolute environment without a reference, measurement methods using acceleration sensors and tilt gyroscopes are typically employed. However, the influence wave forces on platforms can cause coupling between different degrees freedom, resulting significant disturba...

A ship’s roll dynamics is sensitive to the mass and mass distribution. Changes in these physical properties might introduce unpredictable behavior of the ship and a worst-case scenario is that the ship will capsize. In this paper, a recently proposed approach for online estimation of mass and center of mass is validated using experimental data. The experiments were performed using a scale model...