International Shipbuilding Progress - Volume 37, issue 410

Authors: Keuning, J.A.

Article Type: Research Article

DOI: 10.3233/ISP-1990-3741001

Citation: International Shipbuilding Progress, vol. 37, no. 410, pp. 123-150, 1990

Authors: Chen, Yung-Hsiang | Bertran, Ines M.

Article Type: Research Article

Abstract: A parametric study of the vertical free vibrations of a ship hull is presented. All the effects of the rotary inertia of mass, shear distortion, thrust force, shear lag, and various damping components are taken into account in analysis. The importance of these parameters to ship-hull vibrations is discussed. The method of calculating the overall damping ratios is included and particularly emphasized.

DOI: 10.3233/ISP-1990-3741002

Citation: International Shipbuilding Progress, vol. 37, no. 410, pp. 151-163, 1990

Authors: Warikoo, R. | Haddara, M.R.

Article Type: Research Article

Abstract: The free vibration of a rotating ship propeller blade is studied using an iterative scheme based on Galerkin's method. The blade is idealized as a cantilever beam with variable cross section of airfoil shape. The effects of pitch angle, shear deflection, rotary inertia and speed of rotation are studied. Agreement with results available in the literature and with results obtained using a finite element method is excellent.

DOI: 10.3233/ISP-1990-3741003

Citation: International Shipbuilding Progress, vol. 37, no. 410, pp. 165-176, 1990

Authors: Nayfeh, A.H. | Sanchez, N.E.

Article Type: Research Article

Abstract: An analytical procedure is presented for the prediction of the stability and complicated responses of a vessel rolling in regular seas. The effectiveness of the technique is demonstrated by considering unbiased and biased ships rolling in regular beam seas, where the relative waveslope and the frequency of encounter can be alternatively changed. The procedure generates bifurcation diagrams showing the regions of the parameter space where instabilities and deterioration of seaworthiness occur so that the designer can assess the dangers and overall seaworthiness of the craft under a variety of sea conditions.

DOI: 10.3233/ISP-1990-3741004

Citation: International Shipbuilding Progress, vol. 37, no. 410, pp. 177-198, 1990

Authors: Demirel, Vedat | Wang, Shen

Article Type: Research Article

Abstract: Navigation of large ships over a dredged channel often experiences some unusual movements which do not commonly occur in an otherwise unrestricted waters. In particular, these distinctive and abrupt movements are more noticeable in the horizontal motions than in the vertical motions. This phenomenon, long been experienced by pilots navigating over dredged waterways, is indeed a hydrodynamic response of wave trapping inside the channel. For some particular matching of ship beam with the channel bank clearance, at some critical depth of the overbank, a ship may experience an unusual sharp increase or decrease of hydrodynamic pressure over the ship hull. …This paper investigates the two-dimensional nature of this phenomenon. The problem for a two-dimensional body of arbitrary cross section oscillating on the free surface of a trenched channel is formulated and solved by a numerical boundary element technique. Results of the added mass and damping coefficients for a rectangular form hull are presented. The effects of the relative dimensions between the ship's beam, draft and the trench width, depth as well as the channel overbank depth are examined. Show more

DOI: 10.3233/ISP-1990-3741005

Citation: International Shipbuilding Progress, vol. 37, no. 410, pp. 199-215, 1990