http://hdl.handle.net/1721.1/7685 2013-05-25T12:26:32Z http://hdl.handle.net/1721.1/74992 Development of an early stage ship design tool for rapid modeling in Paramarine Thurkins, Eric J., Jr In early-stage ship design, it is helpful to perform preliminary design and analysis on many configurations to assist in developing and narrowing the trade space. This process is further complicated with the increasing interest in concepts that are breaks from previous practice, such as Integrated Power System (IPS) designs, which require initial development to go deeper than historically based parametrics can provide. Paramarine is a ship design and analysis tool which can be used in this early-stage design; however, as with many early-stage design tools, the fleshing out of diverse ideas in Paramarine can be time and resource consuming. In an effort to enable a developer to create early-stage designs with depth significant enough to be meaningful but still general enough to allow the level of flexibility in design required in the early stages of development, this project seeks to develop an Early Stage Ship Design Tool (ESSDT). This ESSDT is a novel interface with which a designer can rapidly develop and alter basic, major design components of a ship from a compiled database of components and gain a rendered model for analysis within the naval design tool Paramarine. By making use of many early-stage parametric and developed calculations and leveraging the use of IPS, this ESSDT automates many of the initial ship's estimates and minutia of design. Utilizing both Excel and Paramarine software, the ESSDT rapidly creates a visual model of a basic naval vessel with primary systems and equipment from relatively few initial user inputs while embodying a depth of user-changeable default settings for more complex and non-standard design efforts. Several case studies were run to show the capability and flexibility of the tool, as well as showing how new powering and mechnical systems can affect the parameters of the ship as a system of systems. Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 85). 2012-01-01T00:00:00Z http://hdl.handle.net/1721.1/74982 Numerical analysis of a shear ram and experimental determination of fracture parameters Koutsolelos, Evangelos The human, economic and environmental disaster that followed the Deepwater Horizon catastrophe at the Gulf of Mexico in April 2010 revealed how much the offshore drilling industry relies on the Blowout Preventer (BOP) as the primary means of controlling a 'well kick' or 'blowout'. One of the most important components of the BOP are the shear rams which are tasked with cutting the drilling string in case of an emergency, allowing the blind rams and the annular type blowout preventer to seal the wellbore and generally prevent things from becoming unmanageable. The increased drill pipe material strength, the fact that its diameter and wall thickness are eventually optimized (larger and heavier pipe sizes) and the greater water depths in combination with the high drilling fluid density affect the BOP's ability to shear. This study investigates all stages of the shearing process and attempts to optimize the geometry of the shear blades. In order to do that, simulations are conducted with Finite Element Models (FEM) by utilizing the Impact and Crashworthiness Lab's (ICL) fracture methodology, the backbone of which is the Modified Mohr-Coulomb (MMC) fracture criterion. Nine cases which involve three different angles defining the sharpness (cutting angle) and three angles characterizing the shape of the blades are evaluated. The optimum configurations for the shear blades are investigated based on the maximum required cutting force and the sealing capability. The simulations are performed for the TRIP 690 steel as well as for the X70 grade steel. The fracture and plasticity parameters for the X70 grade steel are experimentally determined in the ICL lab as part of this research. In addition, recommendations for shearing the tool joints, the connections of the drill pipes, are made based on the Finite Element (FE) simulations. Finally, as a second application of the MIT's fracture prediction capability, the process of fracture of a pre-cracked drill pipe is solved numerically and compared with the response of an uncracked drill pipe. Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 127-129). 2012-01-01T00:00:00Z http://hdl.handle.net/1721.1/74902 Remote nondestructive evaluation of composite-steel interface by acoustic laser vibrometry Emge, Timothy James, II Composite materials are increasingly being used in both civil and ship structures. In particular, fiber reinforced polymer (FRP) composites are being utilized. FRP materials are most often employed to reinforce aging or damaged portions of civil structures. On naval vessels, FRP materials are incorporated to reduce weight, particularly up high, and to reduce radar cross section, thereby increasing stealth capability. In both cases of FRP use, it is usually in conjunction with some other material, oftentimes steel. It is beneficial when using FRP and steel to adhesively bond them together. When these materials are joined adhesively, the most common failure mode is debonding or delamination at the interface of the adhesive with the steel and composite materials. These defects are often difficult to discern without the aid of some form of nondestructive testing (NDT). Acoustic laser vibrometry is a relatively new method of NDT that shows a lot of promise in analysis of this interface. In this approach, an airborne acoustic wave is utilized to excite the location of the damage underneath the FRP sheets/plates and the target vibration is measured using a laser vibrometer. To study the acoustic laser method, a defect specimen was created from a plate of AL6XN stainless steel and a plate of glass FRP adhesively bonded on their faces with a purposely placed elliptical debonding defect. A number of parameters of the acoustic laser vibrometry system were varied and trends were found. Additionally, grid data was collected from the defect specimen and a defect mapping was created. Theoretical and finite element models were produced and compared to measured results. The close correlation of the results from these three methods validated them all. Thesis (Nav. E. )--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 70-73). 2012-01-01T00:00:00Z http://hdl.handle.net/1721.1/74898 Autonomous adaptation and collaboration of unmanned vehicles for tracking submerged contacts Privette, Andrew Jamie Autonomous operations are vital to future naval operations. Unmanned systems, including autonomous underwater vehicles (AUVs) and autonomous surface vehicles (ASVs), are anticipated to play a key role for critical tasks such as mine countermeasures (MCM) and anti-submarine warfare (ASW). Addressing these issues with autonomous systems poses a host of difficult research challenges, including sensing, power, acoustic communications, navigation, and autonomous decision-making. This thesis addresses the issues of sensing and autonomy, studying the benefits of adaptive motion in overcoming partial observability of sensor observations. We focus on the challenge of target tracking with range-only measurements, relying on adaptive motion to localize and track maneuvering targets. Our primary contribution has been to develop new MOOS-IvP autonomy and state estimation modules to enable an autonomous surface vehicle to locate and track a submerged contact using range-only sensor information. These capabilities were initially tested in simulation for increasing levels of complexity of target motion, and subsequently evaluated in a field test with a Kingfisher ASV. Our results demonstrate the feasibility, in a controlled environment, to localize and track a maneuvering undersea target using range-only measurements. Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.; Cataloged from PDF version of thesis.; Includes bibliographical references (p. 103-106). 2012-01-01T00:00:00Z