The equations of motion of a suspended, inextensible cable in
the absence of damping are studied. A method is developed and
illustrated for determining the frequencies and mode shapes for small
oscillations about the equilibrium configuration.
With the introduction of a new variable, the fourth order equation
governing tangential displacement...
Short non-flexible elements of cable were driven harmonically
in water while constrained by springs. The cable elements were observed
to oscillate at approximately the Strouhal vortex shedding
frequency. Damped resonance occurred near the point where the natural
frequency and the Strouhal vertex shedding frequency were equal.
Transverse oscillation amplitudes greater...
The equations of motion of an elastic cable suspended in a
viscous medium from two arbitrary points are derived. These are
then linearized for the undamped, inextensible case, and it is found
that the equations describing the in-plane motion of the cable are
then independent of the equation describing the...
The anchor-last mooring procedure is investigated in order to determine the transient forces in the mooring line and the velocities of the anchor. Transient forces were determined and the results showed that no severe snap loads occurred for the cases investigated. In addition, it was found that the vertical velocity...
The utilization of extra-high-voltage underground power cables
over distances greater than 100 miles presents serious problems relative
to the voltage and current limits of such cables. These problems
are directly associated with the fixed amount of capacitance inherent
in long cable lines. As a result, large charging currents are
characteristic...
Two-way transmission of data on broadband community cable television systems is considered in this thesis. A discussion of the data transmission environment is presented which attempts to characterize the channel noise and interference which degrades data transmission performance. The analysis considers channel degradation resulting from additive gaussian noise and various...
The design and analysis of single point power-mooring cables applied to wave energy converters (WECs) is presented. WECs are mechanical devices designed and deployed to extract energy from waves in varying ways, and at varying distances from the shoreline. WEC devices operating on the water surface require mooring lines or...
Computer oriented techniques and procedures are presented for the analysis of single and multiple cable systems. Application is made to a two-point mooring system influenced by surface and subsurface hydrodynamic loading. The effects of the various parameters are presented and the numerical method is compared to exact solutions obtained from...
The nonlinear dynamic analysis of cable and membrane structures
is presented in this study. Attention is given to the nonlinearities
arising from large displacements, from nonlinear stress-strain
relationships and from nonconservative loadings.
The finite element method is used to model the cables and
membranes. Curvilinear geometries of the elements are...
Cables used in the ocean are often constructed of helically wound
wires or strands. Tension in the cable induces torque and/or rotation
about its longitudinal axis. A method is presented to determine the
tension, torque, location and angular orientation of points on the
cable centerline, using a shooting method algorithm...
Long bridges tend to develop large deformations under the
action of intense dynamical loads such as wind or earthquakes.
Unless these deformations are controlled in some fashion, the
structure might suffer damage or even collapse. One possible
solution to this problem is to apply external forces to the
bridge through...
An optimization methodology, algorithms, and computer program for
cable/lumped-body deployment system are developed for the design and installation of
sonar packages in deep ocean ranges. In addition, a methodology and algorithms for the
control of the system are proposed.
A penalty function is developed in terms of the system parameters...
Time-domain models were developed to predict the response of a tethered buoy
subject to hydrodynamic loadings. A coupled analysis of the interaction of a buoy and
its mooring is included and three-dimensional response is assumed. External loadings
include hydrodynamic forces, tethers tensions, wind loadings and the weight of both
cable...
This dissertation studies the coupled fluid-structure interaction (FSI) of a wave energy converter (WEC) and evaluates the design of a WEC mooring system. The research is conducted in support of conceptual development, field test and performance evaluation of WECs as part of the mission of the Northwest National Marine Renewable...
Modern variable speed machine drive (VSMD) systems are used for a variety of purposes including generation, propulsion, pumps and compressors. They employ high switching frequency power electronics to drive the electric machine. The machine is subject to large voltage overshoot if long power cables, are used, called Reflected Wave Phenomena...
The dissertation uses state-of-the-art structural engineering theories, in parallel with the modern and still-developing control theory of electrical engineering to mitigate the vibratory responses of a double-stayed bridge subjected to strong earthquake ground motions.
First, a nonlinear finite element model of the double-stayed bridge subjected to non-uniform (multi-support) earthquake excitations...
As interest grows in developing devices to harvest energy from ocean waves, tidal currents, and offshore wind, concerns over possible environmental effects from such devices also grow. One such concern is over the induced electric fields and the generated magnetic fields from generators and their associated submarine power cables in...