Showing papers by "Nilanjan Saha published in 2020"
TL;DR: The study shows that there is a significant variation vis-a-vis the deterministic responses unless the modelling is done in a proper framework, and the importance of the Milstein method in handling a range of ocean nonlinear problems is brought out.
2 citations
01 Jan 2020
TL;DR: In this article, the authors investigate the issues encountered by the torpedo anchor during the vertical drop, which ultimately reduces the pull-out resistance, and the effect of the anchor tilt on pullout resistance is studied.
Abstract: A novel technique of dynamically installing torpedo-shaped anchors is investigated. A vast extent of uncertainties arises in pull-out capacity estimation due to the excessive tilt of a torpedo anchor during free-fall and subsequent embedment into the seafloor. This paper will investigate the issues encountered by the torpedo anchor during the vertical drop, which ultimately reduces the pull-out resistance. The pull-out resistance study offered by torpedo anchors is investigated using a finite element tool, PLAXIS 3D. A series of pull-out tests were conducted with anchors under four different ballast conditions (20, 40, 60 and 80%) with three chosen fin configurations (without fin, 3 fins and 4 fins). The anchors are tested for various inclinations (0°, 2.5°, 5°, 7.5° and 10°) and the effect of torpedo anchor tilt on pull-out resistance is studied, and the allowable range of anchor tilt was recommended. Thus, this study provides the benefit of ideal ballast and fins arrangements.
01 Jan 2020
TL;DR: In this article, the effect of loading direction (0° −90°), diameter ratio (1.02, 1.07 and 1.13), and fin ratio (0, 25, 50 and 75%) on the performance of a torpedo anchor was evaluated.
Abstract: Anchor is used from the olden times to support the vessels either on/near the shore or deep in the oceans. These anchors are not only capable of mooring normal vessels but also the floating offshore structures. Earlier using Plaxis 3D, the effect of the remolded zone, amount of ballast, tilt angle and fin configuration are studied numerically and compared to established theoretical and field studies. In this paper, the parameter study was extended by considering the effect of loading direction (0°–90°), diameter ratio (1.02, 1.07 and 1.13) and fin ratio (0, 25, 50 and 75%) of torpedo anchor. All the above-mentioned parameters are evaluated for the varying ballast and fin configurations. From this study, it was concluded from the effect of loading direction that torpedo anchor is well suited for catenary mooring system. Since they are good enough to hold the horizontal load while offering minimal vertical resistances enables poor performance in taut mooring systems. If semi-taut mooring lines are used, then mooring lines angles at the mud line should not be more than 60°.