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 25 for “"stiffness ratio"”.
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Effects of Corrugations on Stiffness Properties of Composite Beams for Structural Applications
<p>Composites have high strength-to-weight ratios, which is particularly desired for applications with weight restrictions. Common composite materials such as carbon fiber reinforced plastic (CF) and fiber glass reinforced plastic (FG) were used in this research. While composite materials possess …
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Improvement of inelastic performance for friction damped asymmetric buildings
… (slip load eccentricity) negative that of stiffness eccentricity on the performance of friction damped braced frames, in an effort to improve the efficiency of friction damped braced frames in single and multi-storey buildings. Firstly, multi-storey models having stiffness ratio (brace …
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Characterization of Fractures Subjected to Normal and Shear Stress
… experiments to determine fracture specific stiffness, for a fracture subjected to shear and normal stress, are presented and analyzed. The experimental work focuses on the determination of relations between normal and shear fracture specific stiffness and between spatial distribution of …
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Parameters Influencing Seismic Structural Collapse with Emphasis on Vertical Accelerations and the Possible Related Risks for New and Existing Structures in the Central and Eastern United States
… associated with the SDOF models — the lateral stiffness, the post-yield stiffness ratio, the yield strength, and the stability ratio (P-Delta effects). Then, three parameters were associated with the ground motions — the records themselves, the lateral ground motion scales, and the vertical …
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Geometrically Nonlinear Aeroelastic Scaling
… that internal loads can be insensitive to axial stiffness, even for globally indeterminate structures. A derived transverse to axial stiffness ratio can be used as an indicator of axial stiffness importance. Two findings of the work extend to geometrically linear applications: new sources of …
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Scaling laws for stress and energy for interface with strong rate-weakening friction
… parameters characterizing the model: the stiffness ratio and strength of the velocity-weakening. Longtime investigations suggest that firstly, a pulse- like brittle behavior would likely to happen for stiff springs and a creep (ductile behavior) would likely to happen for weak springs; …
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The Correlated Dynamics of Micron-Scale Cantilevers in a Viscous Fluid
… systems that include a variety of configurations and viscous fluids. It is first shown that the correlated dynamics of both a laterally and vertically offset cantilever pair can be accurately predicted by numerical simulations. This is verified by comparing the correlated dynamics yielded …
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Buckling patterns on pre-stretched bilayer shells
… varying the pre-stretch of the substrate and the ratio of film stiffness to substrate stiffness. The phase diagram of the system exhibits a variety of buckling patterns: from the classic periodic wrinkle to creases, folds, and high aspect ratio ridges. Our system is capable of easily transitioning …
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Graphs and tables for the analysis and design of curved concrete beams
… 90, 120, 135, 150, 165 and 180 degrees and whose stiffness ratio: (K) are 1.33, 2, 4, and 10.67. Special emphasis has been given to reinforced concrete curved beam design as based on the theories and experiments presented in the literature by Timoshenko and Gowan. The investigation shows that many …
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Three-dimensional multi-scale hydraulic fracturing simulation in heterogeneous material using Dual Lattice Model
… lattice model. The magnitude increases with the stiffness ratio of shear spring to normal spring. Fracturing process can be modelled by LEM by introducing a microscopic tensile strength and a microscopic shear strength to the lattice properties. The strength parameters can be related to fracture …
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The behaviour of modern flexible framed structures undergoing differential settlement
… structural behaviour to the soilstructure stiffness ratio, secondly the importance of 3D deformation of the structure and thirdly that stiffer load-displacement responses of foundations may also affect the behaviour of the structure. A stiffer load-displacement response may occur with the …
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An experimental investigation into the stress-dependent mechanical behavior of cohesive soil with application to wellbore instability
… specimen geometry, preshear lateral stress ratio, drainage conditions, consolidation stress level, stress history, and cavity volumetric strain rate. This testing program has been performed using small and large TWC devices with outer diameter, Do=7.6cm and 15.2cm, respectively. Both devices …
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Twist error response of periodic lattices to strain energy distribution
… angular wall error depends on the torsional stiffnesses of the panels, the initial fold angle of the preformed accordion unit in the lattice and the angular wall error. A FEA simulation study quantified the Buckingham Pi results by varying the torsional stiffness ratio of the panels, the …
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Analysis of Static and Dynamic Deformations of Laminated Composite Structures by the Least-Squares Method
… basis functions with the LGL nodes taken as integration points are used to approximate the unknown field variables, the methodology yields a system of discrete equations with a symmetric positive definite coefficient matrix. The main goal of this research is to determine the efficacy of the LSFEM …
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Unraveling rugae in compressed fiber-reinforced bilayers - New scaling laws for wrinkling, symmetry breaking, and beyond
… such composites. The latter accounts for concentration-mediated fiber stiffness, orientation, and dispersion. The analysis reveals two distinct wrinkling regimes, primarily governed by the elastic stiffness ratio between the film and the matrix, namely the mismatch between the two. Each regime is …
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Digital Simulative Test of Asphalt Mixtures Using Finite Element Method and X-Ray Tomography Images
… study the effect of major parameters such as the stiffness ratio of the networks on the macro response of the model. The simulation results obtained shows a good agreement with the experimental results. The dissertation also presents a method to measure micro strains in asphalt mixture. An …
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Multi-resonant Electromagnetic Shunt in Base Isolation for Vibration Damping and Energy Harvesting
… effectively mitigate the earthquake induced vibrations of low- or mid-rise buildings, and at the same time to efficiently harvest utility-scale energy by using an optimally configured multi-resonant electromagnetic shunt in base isolation. In this research, two multi-resonant shunt …
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Interlaminar stress analysis of dropped-ply laminated plates and shells by a mixed method
… domain is reduced to one dimension by integration through the thickness. Continuity of tractions and displacements between layers is imposed. The governing two-point boundary value problem is composed of a system of both differential and algebraic equations (DAEs) and their associated …
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Experimental and Numerical Investigation of Droplet Formation and Material Interactions Under Different Conditions
… (e.g. droplet shape, length, volume, separation time). The numerical data was correlated with an analytical solution based on pressure and velocity data from a mathematical approach and experimental; works on model materials with different properties. The program has been used to establish …
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Wrinkling of Membrane and Thin Film under Torsion
… and the wrinkle patterns are sensitive to the ratio of inner radius and thickness, but are insensitive to the size of the outer radius as long as it is above several times of the inner radius. The effect of stiffness ratio of the film and the substrate is similar to that of pre-tension in the …
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