Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 71 for “"beam model"”.
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Reconciliation of a Rayleigh-Ritz beam model with experimental data
… modification on a structure, an analytical model which sufficiently describes the behavior of the structure must be developed. Analytical models can be generated for almost any structure, but such a model will generally not effectively predict the behavior of the structure unless the model …
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A Finite Difference Approach to Modeling High Velocity/Variable Loads using the Timoshenko Beam Model
… heavily upon a comprehensive understanding of beam behavior during periods of heavy dynamic loading. It is hypothesized that the combination of velocity transition effects, electromagnetic loading, and other non-linear or design specific effects contribute to areas of high stresses/strains over …
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A parametric study of the stress distribution in a four-celled box beam model of the ASR-21 Class Catamaran cross-structure.
Thesis: Ocean E., Massachusetts Institute of Technology, Department of Ocean Engineering, 1972
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Vibration and Aeroelasticity of Advanced Aircraft Wings Modeled as Thin-Walled Beams--Dynamics, Stability and Control
… on a refined analytical anisotropic thin-walled beam model, aeroelastic instability, dynamic aeroelastic response, active/passive aeroelastic control of advanced aircraft wings modeled as thin-walled beams are systematically addressed. The refined thin-walled beam model is based on an existing …
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Analysis of multifrequency interferometry in a cylindrical plasma
… project. Standard data analysis based on a thin beam model neglecting refraction yields inconsistent electron densities and density profiles for different frequencies. This work focuses on the development of a model for the wave propagation through cylindrical plasmas when the plasma radius is on …
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An Investigation of Beam-to-Column Connections for Composite Structural Systems
I-beams with angle connections are becoming the standard framing method for composite structures. We claim that closed sections are often a more appropriate member selection. We also present the cuff connection; a novel beam-to-column connection element suited to closed structural members. We …
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Integrated structural design, vibration control, and aeroelastic tailoring by multiobjective optimization
… variables were derived for a finite element beam model of the structure and constant feedback gains determined by Independent Modal Space Control. Pareto optimal designs generated for a simple beam and a tetrahedral truss demonstrated the benefit of solving the integrated structural and …
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Evaluation of Intensity Modulated Radiation Therapy (Imrt) Delivery Error Due to Imrt Treatment Plan Complexity and Improperly Matched Dosimetry Data
… distribution calculated using a different 6MV beam model. Radiochromic film and TLD within the phantom were used to analyze the dose profiles and absolute doses, respectively. The measured and calculated were compared to evaluate the dosimetric accuracy. All deliveries met the RPC acceptance …
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Finite element model of thermoelastic damping in MEMS
… expressions for thermoelastic dissipation in a beam model. The governing equations of thermo elasticity dictate that the amount of damping that a resonator undergoes is a function of both material properties as well as device geometry. Damping will become greatest at operating cycle times that …
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Curved beam based model for piston-ring designs in internal combustion engines
… and conformability. This study based on straight beam model was already developed but does not consider the lubrication sub-models, the tip gap effects and the characterization of the ring free shape based on any final closed shape. In this work, three numerical curved beam based models were …
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Three-dimensional routed manifolds with externally inserted cables
… and must therefore be prevented. To this end, models have been developed to predict the force required to push wires into a predetermined path. Relatively good experimental agreement, within 20% in many cases, was achieved for paths with radii of curvature to wire diameter ratios between 200:1 …
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Experiments and simulations of large-angle flexible beam control using an adaptive truss
… adaptive truss with an appended flexible beam. Three cases are studied. The first case is an experimental and analytical investigation of flexible beam control using an adaptive truss positioned in an equilibrium configuration such that the beam is parallel to the gravity field. A linear …
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Active damping of a structure with low-frequency and closely- spaced modes: experiments and theory
… investigation of active damping on a cruciform beam laboratory structure along with the development of this structure. Also important to this and other research was the development of a calibration apparatus that produces accurate, repeatable calibrations for several types of laboratory …
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Buckling and growth of disbonds in honeycomb sandwich structure
… disbond growth and, consequently, models of buckling and disbond growth were developed. All of the models decoupled the face-sheets of the sandwich and treated the core as a spring foundation having a stiffness determined from equilibrium of a two-dimensional orthotropic solid. A …
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Modeling Cable Harness Effects on Space Structures
… of cabled structures must be understood and modeled for accurate spacecraft control. Models of cable behavior are reviewed and categorized into three major classes consisting of thin rod models, semi-continuous models, and beam models. A shear beam model can predict natural frequencies, …
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Verification and validation of the geometrically exact beam theory with Legendre spectral finite elements for wind turbine blade analysis, A
… engineering (CAE) tools that are capable of modeling the nonlinear behavior of composite structures with complex geometry in a robust yet computationally efficient manner. The National Renewable Energy Laboratory (NREL) has developed an aeroelastic CAE tool, FAST, which is used for wind …
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Creep predictions for turbomachinery components
… for rectangular or circular cross section beams under bending and tensile loads are presented. Comparison with data for a Ni Superalloy showed life predictions could be 30X in excess of experimental values. This beam model also revealed that it is imperative that no bending moments be …
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Pencil beam dose calculation for proton therapy on graphics processing units
Radiotherapy delivered using scanned beams of protons enables greater conformity between the dose distribution and the tumour than conventional radiotherapy using X rays. However, the dose distributions are more sensitive to changes in patient anatomy, and tend to deteriorate in the presence of …
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Materials and device design for MEMS piezoelectric mechanical vibration energy harvesters
… electronics, and fabrication of devices, modeling is an indispensable element in predicting and designing PVEHs. Here, an improved electromechanically-coupled model is developed including the ability to analyze proof mass effects and different electrode configurations. Although essential …
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An investigation of space suit mobility with applications to EVA operations
… to bend the joints of a space suit, developing models of the mechanics of space suit joints based on experimental data, and utilizing these models to estimate a human factors performance metric, the work envelope for space suited EVA work. A detailed space suit joint torque-angle database is …
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