Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000. / Includes bibliographical references (p. 75-76). / A robotic mechanism is described, called Robopike. The robot has fork length equal to 82cm, and contains 5 motors, a computer and a wireless modem for communication during testing. Details of the construction and testing methods are provided. The testing covered only a small part of the extensive parametric range, and resulted in speeds up to 0.11 body lengths per second and turns of 350 in two seconds. The kinematics of the robot are quantified and analyzed. A non-dimensional number, the Maneuvering Strouhal Number (Stm) is defined based on observations from live fish and previous theoretical developments. Recommendations for further improvements in the maneuvering performance of flexible hull vehicles are derived based on the Maneuvering Strouhal Number (Stm). / by John Muir Kumph. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 69-70). / Investigations into unsteady flapping foil propulsion have shown that it is an efficient and high thrust means of propulsion. Extensive work has been done to optimize the efficiency of two-dimensional flapping foils, varying both the kinematics of the motion and the flexibility of the foil. However, no thorough investigation into the hydrodynamic efficiency of three-dimensional flapping foils has been made. In this thesis, experimental hydrodynamic efficiency measurements and force measurements of a three-dimensional flapping foil are presented. These measurements were made by mounting a small, six-axis dynamometer directly onto the foil shaft of a flapping foil module. The module uses two computer controlled servo motors to actuate a foil in a sinusoidal pitch and roll motion, similar to the motion of a penguin's wing. The measured thrust coefficients compared well to previous experimental results, and the on-shaft dynamometer proved to be a valuable sensor. However, the experimental apparatus must be modified before reliable efficiency results can be made for the entire range of kinematics. / (cont.) Once these improvements are made, a thorough investigation into the effects of foil geometry and flexibility can be done to find the optimum efficiency parameters of a three-dimensional flapping foil. These optimum efficiency parameters will be valuable for the development of flapping foil vehicles. / by Karl-Magnus Weidmann McLetchie. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 100). / A study was carried out to develop and test techniques for the computational optimization of hydrofoil sections and lifting surfaces advancing under a free surface. A mathematical model was developed based on the extension of a two-dimensional potential flow solution to account for three dimensional effects. Prandtl's lifting line theory was used to account for induced drag and downwash at the leading edge of the foil. Strip theory was used to extend the two-dimensional wave drag solutions to three dimensions for high aspect ratio foils. A semi-empirical correction was added to account for viscous drag. The drag-to-lift ratio of foil sections and lifting surfaces were optimized using first order gradient techniques. Optimization studies involving submerged foil sections suggest that trading buoyancy for a reduction in wave drag will lead to optimal geometries. Difficulties encountered resulting from the adoption of a potential flow model were identified and discussed. The lifting surface optimization was carried out using the coefficients of Glauert's circulation series as design variables. At high speeds it was shown that non-elliptical loading can produce reductions in the drag-to-lift ratio of a lifting surface. Induced drag dominated the low-speed optimization, and elliptical loading was shown to be optimal at the low end of expected operating speeds of a hydrofoil vessel. An adjoint formulation for the problem of optimizing the shape of a lifting section under a free surface was derived for use in future research. / by Gregory Michael Tozzi. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2002. / Includes bibliographical references (leaves 51-52). / by William E. Duncan. / S.M.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1988, and (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1988. / Bibliography: leaf 84. / by Athanassios A. Dimas. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001. / Includes bibliographical references. / by Michael L. Malone. / S.M.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. / Includes bibliographical references (p. 65). / The use of double hull construction is commonplace within the shipping industry though it is largely unexploited within naval vessels. The Impact and Crashworthiness Lab at MIT has proposed the use of adaptive sandwich structures to improve the blast resistance of naval hulls. This project will address two main areas of investigation through the use of simplified analytical models: the integration of hardening and softening plastic core responses in the crushing of a rigidly supported sandwich panel; and the deformation analysis of a sandwich panel supported by non-rigid connections. The analytical solutions were utilized to perform a series of parametric studies to evaluate both the useable range of the models as well as to investigate the general behavior of a sandwich panel under a uniform load when supported by crushable connections. This initial investigation provides the simplified tools to begin and to validate a more detailed, numerical analysis. / by Christian R. Brown. / S.M.

Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1991, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1991. / Includes bibliographical references (leaves 85-87). / by Richard Alan Jinkerson. / M.S. / Nav.E.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994. / Includes bibliographical references (p. 141-145). / by Grant B. Thornton. / M.S.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001. / Includes bibliographical references (leaves 147-153). / by Georgios Papaioannou. / S.M.