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ABSTRACT: An optimization methodology and algorithms for cable/lumpedbody deployment systems are developed for the design and installation of sonar packages. Alternating Direction (ADM) and Modified Alternating Direction (MADM) methods are employed for the optimum search. The optimization algorithms are implemented on a desk-top computer. Examples demonstrating the optimal paths are delineated. 1 INTRODUCTION 1.1 Background As part of an effort to improve the installation procedure of sonar packages on the sea floor of a deep ocean range, the development of computer simulation techniques for optimization of cable/lumped-body installation is needed. Given an optimum acoustic design of a deep ocean range, it is necessary to evaluate the design of the installation procedure to ensure the most expedtious installation of the system for optimal performance. A typical scenario for installation of a deep ocean range is a sequential pay-out from a surface vessel of several single cables with discrete nodes spaced at appropriate lengths along the cable such that the nodes are positioned along an irregular path on an irregular sea floor. Minimization of the installation cost and/or time is a prime consideration while satisfying specified tolerances in the location of the installed nodes and structural integrity of the system. The optimum sequences of vessel headings and speeds and of pay-out velocities are sought within the constraints dictated by the site conditions, cable and equipment characteristics and the acoustic design. The terminology and algorithms to build a suite of computer programs to design and install cable/lumped-body system already exist. However, existing programs are intended for analysis of well-posed problems with accurate descriptions of loading conditions and system characteristics, rather than for interactive design of systems to achieve optimum performance. 1.2 Previous Studies Research was conducted at Oregon State University to develop a dynamic response simulation method for cable/lumped-body systems.
- North America > United States > Oregon (0.34)
- North America > United States > Connecticut (0.28)
ABSTRACT: The equations of motion for small tethered buoys floating in a nonlinear wave field have been developed. The coupling between rotational and translation3.I degrees of freedom is included in the equations and a three-dimensional response is assumed. The floating buoy is treated as one boundary condition of the governing differential equations for the mooring line coupled buoy-mooring problem. INTRODUCTION In this paper the coupling effects of rotational degrees of freedom of tethered floating buoys with the governing equations of the tether are considered. The cable algorithm is described in the following section. The equations of motion for tethered floating buoys in terms of the six degrees of freedom in translation and rotation, which constitute the boundary conditions for one end of the tether, are developed. An algorithm for quasi-linearization of those boundary conditions, which are used in determining the tether motions and buoy rotations for the coupled nonlinear system, is developed and. presented in a subsequent section. Validation of the methodology is provided in the final section. Buoys and their moorings are considered in this work to be classified as small bodies for which the relative-motion Morison equation may be adopted (Sarpkaya and Isaacson, 1981). A coupled analysis is needed for this ocean structure, since the motion of the buoy affects the motion of the mooring and visa versa (Berteaux, 1976). CABLE ALGORITHM An iterative algorithm of dynamic analysis of hydrodynamically loaded cable has been developed by Chiou and IISOPE Member Leonard (1991) in which the problem is formulated as a two point boundary value problem. The boundary value problem is then transformed into an iterative set of quasi-linearized boundary value problems, which is then decomposed (Atkinson, 1989) into a set of initial value problems so that spatial integration may be performed along the cable (Sun et al., 1993).
- North America > United States > Oregon (0.29)
- North America > United States > Connecticut (0.29)