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Propagation via a Peridynamics Formulation: A Stochastic\Deterministic Perspective
(2011)
Novel numerical methods for treating fractional differential and
integrodifferential equations arising in non local mechanics formulations are
proposed. For fractional differential equations arising in modeling oscillatory
systems incorporating viscoelastic elements governed by fractional derivatives,
the devised scheme is based on the Grunwald-Letnikov ...
Entry guidance for human lunar return vehicles with low lift-to-drag ratios
(2010)
During the entry phase of a human lunar mission, an entry guidance algorithm is used to safely steer the return vehicle through the atmosphere to a target landing site. The PredGuid entry guidance algorithm is enhanced to improve performance and satisfy a set of assumed mission requirements. The enhanced algorithm utilizes an improved numeric ...
Polymer nanocomposites characterization by a stochastic finite elements representation
(2007)
This dissertation introduces a new multiscale stochastic finite element method (MSFEM) for determining the mechanical properties of polymer nanocomposites (PNC) consisting of polymers reinforced with single-wall carbon nanotubes (SWCNT). Obviously, reliable characterization of the various properties of nanomaterials such as PNC is indispensable in ...
Effects of stabilizer bars on road vehicle ride quality
(1994)
In an effort to improve the safety and road-holding capabilities of vehicles, manufacturers have begun a trend toward increasing vehicle body roll resistance by introducing stiffer roll-stabilizer bars. In this study vehicle suspension and road surface models are developed to investigate the effects of such stabilizer bars on ride quality. The purpose ...
Residual flexibility methods for decoupled analysis of integrated structural systems
(1998)
Methods of dynamic analysis of large structural systems used in aerospace applications are examined. Full-system solutions are undesirable due to computational cost and logistics issues. Traditional substructuring methods effectively reduce system size through truncation of component modes, but still require an eigen-value analysis of the integrated ...
Stochastic fatigue analysis of FPSO topside structures with linear and nonlinear supports
(2008)
Floating Production, Storage, and Offloading (FPSO) Systems are quite often subjected to stochastic sea wave loadings. In this thesis, a methodology is developed for estimating the fatigue life of topside structures. Proper Response Amplitude Operator (RAO) of the FPSO system, and the well-known Ochi-Hubble sea wave elevation spectrum are combined ...
Development of stochastic quadratization for nonlinear systems with application to compliant offshore structures
(1990)
The exploration and production of oil at offshore locations is extending into ever increasing water depths. To exploit this resource in water depths in excess of 300 meters, a new class of offshore structures called compliant platforms are being developed. The compliant nature of these platforms introduces nonlinear behavior which can not be neglected ...
An analysis of nonlinear damping and stiffness effects in force-limited random vibration testing
(1998)
The effects of both stiffness and damping nonlinearities on force-limited, random vibration test specifications are investigated. The response of the source-load vibratory system to a random, Gaussian excitation is analyzed using the modal- and residual-mass two degree-of-freedom system. The technique of statistical linearization is used in conjunction ...
Development of a large space robot: A multi-segment approach
(1991)
A multi-segment robot is developed as a concept for use in space based construction operations. The multi-segment robot is envisioned as a member of a class of large space robots, or space cranes, used in the assembly of advanced spacecraft. The problems that arise when the requisite robot size becomes large are explored. The unique capabilities of ...
Iterative determination of spar lines static equilibrium and improved dynamic modeling by fractional derivatives
(2009)
Polyester mooring systems are used as permanent systems of floating production systems and offshore structures. Compared to other mooring systems, polyester has a highly non linear behavior, thus complicating the overall design. Three important parameters affect the polyester rope stiffness; the mean load, the load range, and the frequency of the ...