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...
A New NDT Device for Comprehensive Pavement Maintenance (Theoretical Aspects)
A new nondestructive testing (NDT) device is being developed to detect some precursors to pavement distress. The principle of operation of the device is based upon the generation and detection...
Flow Dynamics in an End-to-End Vascular Graft Junction
A study consisting of both experimental and numerical methods was performed to determine flow dynamics in the vicinity of an end-to-end anastomosis. The experimentally determined geometries...
Flexural and Shear Studies of Carbon Fiber Reinforced Beams
This paper presents the results of laboratory test on beams reinforced with three dimensional continuous carbon fiber grid. The grid is prefabricated by three-dimensional weaving and epoxy...
Modeling Bond Stress-Slip of Reinforcing Bars Embedded in SIFCON
A brief description is given of the mechanisms associated with the bond shear stress versus slip response of deformed reinforcing bars embedded in slurry infiltrated fiber concrete (SIFCON)....
Determination of Interfacial Shear and Normal Stresses in Fiber Pull-Out
In this paper we present an improved formulation for the pullout problem, wherein both the effects of fiber end condition and interfacial and frictional shear stresses are considered....
Failure Prediction of Anisotropic Material
Basic mathematical elements of a higher order failure theory for anisotropic material are outlined. Surface closure is ensured by requiring a tensor polynomial to satisfy constraint conditions....
Microcrack Interaction Toughening in Ceramics and CMCs
The generation of microcracks, which causes an extension of the damage zone at values of stress intensity factor, K, below the expected critical level represented by KIC...
Pattern Formation and Time-Dependence in Flowing Sand
The authors present results for a number of experiments on flowing granular materials and a novel cellular automata model for the flow of these materials when the grains are long and thin....
Modeling the Chaotic Behavior in Simple Shear Granular Flows
Simple shear granular flows have demonstrated a variety of puzzling phenomena. Both computer simulations and physical experiments have discovered particle grouping, layering and shear...
Mechanics of Granular Materials at Very Low Effective Stress Levels
Gravity's influence on laboratory specimens of uncemented granular materials subjected to low effective stresses, makes it impossible to evaluate constitutive properties in an unambiguous...
Thermal Load for p-Version Laminated Elements
A p-version finite element formulation is presented for determining temperature stresses in laminated composite axisymmetric problems. Formulation for a rectangular axisymmetric p-version...
Stresses in Open Section Fiber Reinforced Composite Beams Under Constant Shear Loading
A strength of materials approach from the ply level is used to derive expressions for stresses in statically determinate open section composite beams subjected to constant shear loading....
An Analysis of an Inflatable Module for Planetary Surfaces
Design and construction of a structure on planetary surfaces requires addressing a host of issues not encountered on Earth. A modular quilted inflatable structure consisting of thin membranes...
In-situ Release of Solar Wind Gases from Lunar Soil
A concept is described which has the potential to perform the in-situ heating of the lunar regolith in order to release the solar wind gases. The poor thermal conductivity of the lunar...
Recent Developments of the Carbotek Process for Production of Lunar Oxygen
Carbotek and Shimizu Corporation are conducting joint development work on the further development of the Carbotek Process to produce oxygen from lunar ilemnite by hydrogen reduction. The...
Production of Oxygen by Electro-Reduction of Lunar Ores
Anorthositic Lunar ores contain approximately 42 wt. pct. of oxygen. An electrolytic dissociation of the ore can provide a rich source of gaseous oxygen with silicon, aluminum, calcium,...
Structural Design of the GN&C Navigation Base for the Space Station Freedom
The Space Station Freedom (SSF) pointing accuracy budget requires that the Guidance, Navigation and Control hardware maintain alignment within ? 0.1 degrees of arc. The ring laser gyros...
Orbital Construction of a NTR Mars Transfer Vehicle
This paper examines a reference Nuclear Thermal Mars Transfer Vehicle (NTMTV) in terms of on-orbit construction. The identification of subassemblies, payload manifesting, on-orbit connections,...
Transfer of Terrestrial Technology for Lunar Mining
Terrestrial mining equipment was evaluated for development of concepts and their application to lunar-based mining operations. The major operational differences between terrestrial and...
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