International Shipbuilding Progress - Volume 49, issue 1

Authors: Kumar, Y.V. Satish | Mukhopadhyay, Madhujit

Article Type: Research Article

Abstract: A ship structural analysis software "ASSA" has been developed for the 3-D finite element analysis of Fibre Reinforced Plastic Boats and Ships using a new stiffened plate element. The software is unique and distinct from the existing ship structural analysis softwares due to the elegance of the element in modeling the stiffened panels. The plate element can accommodate any number of arbitrarily oriented stiffeners and obviates the use of mesh lines along the stiffeners. Moreover, the …element does not lock under shear and can analyse both thin and thick plates. The software can analyse all types of FRP vessels. The global analysis of a rectangular box shaped vessel has been carried out with the present software and results compared with the general purpose finite element software NISA. A high speed FRP patrol boat has been analysed and the stresses are presented. Show more

Keywords: Ship, Stiffened plate element, Stiffener, 3-D finite element analysis, Allman's triangle, Discrete Kirchhoff Mindlin Triangle, High speed crafts, FRP vessels

Citation: International Shipbuilding Progress, vol. 49, no. 1, pp. 5-35, 2002

Authors: Lin, Wu-Qiang | Dong, Zhu-Shun

Article Type: Research Article

Abstract: A controllable transom flap on round-bilge boat not only may reduce the resistance at cruising speeds in still water, but also could be designed to make a boat run at or near optimum attitude in various environmental condition which results in a motion reduction in waves. The study is to design a suitable automatic system of controllable flaps to reduce the motion of round-bilge boats in irregular waves. In this paper, considering the controllable flap as an exciting …force and moment, the motion equation of round-bilge boats with controllable flaps have been based on a modified strip theory. The purpose is to improve the feasibility and effectiveness of the controllable flap as a means of pitch- reducing. Model tests make use of an oscillating flap instead of a controllable flap for checking up the effects of pitch- reduction of flaps. Model tests carried out in the ship model towing tank of Huazhong Science & Technology University have shown that using an oscillating flap would reduce pitching motion effectively, if a suitable phase could be established between flap exciting forces and wave disturbances. Show more

Citation: International Shipbuilding Progress, vol. 49, no. 1, pp. 37-51, 2002

Authors: Varyani, K.S. | McGregor, R.C. | Chua, Soo Khoon

Article Type: Research Article

Abstract: The paper aims to describe the initial steps into the study of manoeuvring characteristics of a Trimaran in deep and shallow water. The program is intended to assess the turning performance of a Trimaran at the design stage using minimal and preliminary data regarding main dimensions, line drawings and other relevant available information. It considers the hydrodynamic characteristics of the centrehull for deep and shallow water and also identifies the influence of other parameters on the …turning performance. Verification of the formulations is investigated by comparison with available data and good agreement is found. Show more

Citation: International Shipbuilding Progress, vol. 49, no. 1, pp. 53-78, 2002