An Elastoviscoplastic Model for High Strength Concrete
An elastoviscoplastic model of overstress type is proposed for high-strength concrete in this study. With its viscosity parameters determined with experimental data from the split-Hopkinson-pressure-bar...
Fiber Suppressed Localization in Tension
Tensile fracture in portland cement based fiber composites is studied. Formation and propagation of stable microcracks is examined by means of holographic interferometry. Distributed microcracking...
A Discussion of the Numerical Modeling of Sea Ice Ridging
Pressure ridging, is the failure mechanism of the Arctic pack ice in compression. The large-scale compressive strength of the ice pack is determined by the aggregate of ridge building...
Nonlinear Eigensolver for Exact Vibration Analysis
Vibration analysis of structural systems is concerned with accurately predicting the free vibration modes and frequencies of the vibrating system. This analysis process involves two general...
An Expert System for Impeller Mechanical Design and Analysis
Impeller is the most critical component of centrifugal compressors. The mechanical efficiency and durability of the impeller determines the performance of the compressors. The shapes and...
Numerical Simulations of Diastolic Flow Patterns in a Model Left Ventricle with Varying Degrees of Mitral Stenosis
Blood flow patterns in the left ventricle are undoubtedly influenced by the physical and mechanical state of the natural mitral valve apparatus or the geometry of an artifical valve replacement....
Optimization of Discontinuous Fiber Composites
Discontinuous Random Fiber Reinforced Composites (DRFRC) exhibit different behaviors depending on their microstructural properties. Small fraction of fiber rupture can have a beneficial...
Investigation of Parametrically-Induced Excitation in Concrete Columns
A mathematical model is developed which accounts for the non-linear material characteristic of concrete members. The axial and transverse motions of concrete columns, are found to be second-order...
Macromodeling of Complex Composites
Dimensionally reduced p-version finite elements based on higher order theory are developed for modeling laminated composite plates and shells in the presence of cracks, notches, and delaminations....
Experimental, Physical and Numerical Modeling of Lunar Regolith and Lunar Regolith Structures
An extensive series of laboratory strength and deformation experiments have been performed on a lunar regloith simulant. Results of these experiments are compared to results from experiments...
Enhancing Decision Analysis Techniques for Lunar Base Construction Research
The usefulness of decision analysis concepts applied to lunar base construction research has been demonstrated [Boles 1990]. During the referenced work the authors realized that further...
Experimental Study of Underground Exploration by Auger Boring on a Mars Rover
A system study was conducted on the possibility of exploring Mars using a Mars Rover, and particular efforts were focused on the underground exploration of Mars by an auger boring machine....
Analysis of Two Lunar Oxygen Production Processes
Frequently, chemical engineers must evaluate processes, design systems, and size equipment based on a chemical or physical reaction without the benefit of laboratory data or previous industrial...
A Novel Aerobrake Design for a Mars Lander
A flexible/inflatable aerobrake is proposed for delivering small payloads to Mars as an alternative to propulsion landing. Some results that demonstrate feasibility are presented....
On-Orbit Assembly and Refurbishment of Lunar Transfer Vehicles
Initial flights of space-based manned lunar transfer vehicles (LTV) will require some on-orbit assembly and checkout due to mass and volume limitations of the Earth-to-orbit (ETO) launcher....
Tethers and Their Role in the Space Exploration Initiative
This paper addresses some potential applications for tethers in space, and describes a mission designed to deploy a satellite from a Delta II launch vehicle, by NASA's Small Expendable...
Modeling and Analysis of Doubly Curved Aerobrake Truss Structures
Recent studies have indicated that vehicles designed for a piloted mission to Mars may have their initial Earth Orbit mass reduced by nearly a factor of two if aerobraking is used rather...
Structural Design Methodology of Large Space Structures
This paper discusses considerations and outlines a methodology for structural design of large space structures (LSS) deployed in low earth orbit. It includes definition of mission requirements,...
Design Criteria for an Underground Lunar Mine
Underground excavation and construction techniques have been well developed terrestrially and provide an attractive option for lunar mining and habitat construction. The lunar mine, processing...
Comparison of Micromechanical Models for Elastic Properties
The effective elastic properties for unidirectional composites, as predicted by several analytical micromechanical models are compared for glass/epoxy and graphite/epoxy. A brief review...
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