International Shipbuilding Progress - Volume 12, issue 135

Authors: Said Ahmed, M.H.

Article Type: Research Article

Abstract: By using the plate theory and the energy method an expression has been derived for calculating the buckling stress for transverse framed decks subjected to edge compressive loading and having a certain restraint at the unloaded edges.

DOI: 10.3233/ISP-1965-1213501

Citation: International Shipbuilding Progress, vol. 12, no. 135, pp. 421-428, 1965

Authors: Frankel, E.G.

Article Type: Research Article

DOI: 10.3233/ISP-1965-1213502

Citation: International Shipbuilding Progress, vol. 12, no. 135, pp. 429-436, 1965

Authors: Yeh, Gordon C.K. | Martinek, Johann

Article Type: Research Article

Abstract: As is known, the motion and the pressure distributions of a rigid ship can be obtained by the method of M.A. Todd (DTMB Report 883, 1955). In this paper, an iteration procedure is presented for numerical computation on pure pitching motion of an elastic ship. One can estimate the overall elastic deformations by considereing the ship to be a free free beam of variable mass and variable flexural rigidity along the length. The local elastic deformations can be estimated by considering the ship bottom to be a rectangular plate with various boundary conditions. Then the motion and the pressure distributions …of the elastic ship (whose shape continuously changes with time), replaced at each instant by an equivalent rigid ship, can again by computed by the method of M.A. Todd. This process can be repeated until the desirable degree of approximation is obtained. The concept of replacing the elastic ship by an equivalent rigid ship has its two-dimensional counterpart in F. Weinig’s work (Luftfahrtforschung. vol. 13, no. 5, 1936). Show more

DOI: 10.3233/ISP-1965-1213503

Citation: International Shipbuilding Progress, vol. 12, no. 135, pp. 437-444, 1965

Authors: Bluston, H.S.

Article Type: Research Article

Abstract: The equations of motion of a ground effect machine in lateral motion are stated and estimates of the lateral stability derivatives are obtained. The equations of motion are reduced, for free motion, to a quartic equation in p (the Laplace transform varable) known as the System Characteristic Equation. The roots of this equation, which determine the craft’s lateral stability, are obtained numerically and in terms of the vehicle stability derivatives. The lateral modes are also calculated and the motion is shown to consist of two essentially uncoupled, lightly damped modes. The first mode has low frequency and represents a yaw-sideslip …motion with little roll. The second mode has a somewhat higher frequence and represents a rolling motion with little yaw or sideslip. Finally, the most important derivatives and craft parameters are discovered and the stabilization problem briefly discussed. Show more

DOI: 10.3233/ISP-1965-1213504

Citation: International Shipbuilding Progress, vol. 12, no. 135, pp. 445-455, 1965