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 40 for “"Isotropic material"”.
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Propagation of fluid driven fractures in transversely isotropic material
… the mechanics of hydraulic fractures (HF) in isotropic media is well established, the impact of the anisotropy of natural rocks on HF propagation is still far from being understood. Sedimentary rocks like shales and mudstones are ubiquitous in upper earth crust which are made of fine layers …
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Identification of Transversely Isotropic Material Properties from Cardiac Magnetic Resonance Elastography
… elastography (MRE) has been used to estimate isotropic stiffness in the heart, myocardium has anisotropic material properties with greatest stiffness along the fibre direction. This thesis investigated two methods for determining global transversely isotropic material properties from MRE …
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Dynamic simulation of heart mitral valve with transversely isotropic material model
… simulating, in the finite element setting, the material behavior of heart mitral valve leaflet tissue. First, a mixed pressure-displacement formulation is used to implement the constitutive material behavior with general 3D elements. Second, a shell is formulated that incorporates the 3D …
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Hydrostatic Pressure Testing of a Square-Cross Section Stainless Steel Propellant Tank Manufactured Using Selective Laser Sintering
… selective laser sintering (SLS) exhibit the same isotropic material properties as conventionally made metal parts. This was accomplished by performing a hydrostatic pressure test (HPT) of a metal SLS manufactured propellant tank, constructed for a nano-satellite of the cubesat class. Strain …
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Calculation of Notch Strains Under Multiaxial Nominal Loading
… concentrators in structures of elastic-plastic, isotropic material subjected to proportional and nonproportional multiaxial nominal loading. The method uses anisotropic plasticity theory to define a structural yield surface in nominal stress space that incorporates both the isotopic material …
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In situ measurement of lattice strain using synchrotron radiation and a conical slit system
… the expected value for tensile loading of an isotropic material as the sample was loaded. Potential error sources are discussed in relation to strain measurements and considerations when using the conical slit system are presented.
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Pore Pressure Parameters and Cyclic Resistance Under Generalized Loading
… pore pressure parameter formulations for isotropic material have been extended to cross anisotropic materials, and it was shown that the principles are applicable even for cross anisotropic materials under generalized initial loading conditions.
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Topology and Printing Orientation Optimization of Orthotropic Material for Additive Manufacturing
… the fibers of the printed structures (principal material axes). A modified SIMP (modified solid isotropic material with penalization) method is used with the method of moving asymptotes (MMA) as the optimizer. A detailed description of the formulation and sensitivity analysis are discussed. 2D …
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Applications of trilinear coordinates to some problems in plane elasticity
… two dimensional elasticity are developed for an isotropic material. All these relationships are presented in matrix form - as an aid to finite element stress analysis. Governing equations corresponding to some two dimensional problems in elasticity are deduced for the trilinear system. An …
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Investigation of Taylor impact test of isotropic and anisotropic material through geometrical characteristics of specimens
In this thesis, high strain rate properties of isotropic material (a copper alloy) and anisotropic material (2195-T8 aluminum-lithium alloy) are investigated using Taylor impact tests. Coordinate measuring machines (CMMs) are used to measure the shape of specimens after the deformation. The …
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Assessing the mechanical microstructure of shale by nanoindentation : the link between mineral composition and mechanical properties
… This thesis assesses microstructure and material invariant properties of shale as the link between engineering performance and composition. A comprehensive experimental microporomechanics approach, employing advanced experimental and analytical nanoindentation techniques, provides the …
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Design for Additive Manufacturing: Simultaneous Optimization of Structural Integrity and Minimal Support Structures
… methodologies are proposed. Firstly, a Solid Isotropic Material with Penalization (SIMP) framework introduces a three-stage robust optimization algorithm. Secondly, the Geometric Projection Topology Optimization (GPTO) method inherently integrates overhang constraints by controlling individual …
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Methods to improve indentation results on soft materials and anisotropic biological tissues
… the localized mechanical properties of materials, and it is an increasingly popular technique for studying biological materials. This thesis investigates difficulties and challenges regarding the application of micro-scale indentation. This study first develops a novel approach, namely …
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Bending and warpage of elastic plates
… body in the plane, we demonstrate that four bulk isotropic quadratic elastic theories have fundamentally different predictions with regard to bending behavior. At finite thickness, these qualitative effects persist near the limit of mid-surface isometry, and not all theories predict an isometric …
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Numerical modelling of ocular accommodation process
… the lens. Secondly, given the fact that the lens material possesses both mechanical and optical gradient properties, the contributions of both gradients to the accommodative response of the lens are quantified. Results show that although the lens GRIN play an important role in accommodation, it …
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Design of functionally graded compliant mechanisms using topology optimization
… and stress distributions. A novel modified solid isotropic material with penalization (SIMP) method is adopted for representing local element material properties in FGM structures. The method of moving asymptotes (MMA) is used in conjunction with adjoint sensitivity analysis to find the optimal …
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Paraxial approximations for ultrasonic beam propagation in liquid and solid media with applications to nondestructive evaluation
… elliptical piston transducer radiating into an isotropic material and possibly through a bicylindrically curved interface. The solution takes the form of either a simple analytical formula for some cases or a simple numerical integration over a finite interval for other cases. The second example …
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Development and Prototype Validation of an Additive Manufactured Cubesat Propulsion Tank
… laser sintering meets the requirements, and material properties of a conventionally manufactured tank. Additionally, to see if additive manufactured parts are a viable option to be used in cubesat applications. This was accomplished by designing a model which will be used by the ARAPAIMA …
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Developments in topology and shape optimization
… filter for length scale control. The solid isotropic material with penalization (SIMP) is incorporated to generate black-and-white designs. To resolve the stress singularity phenomenon, we introduce a SIMP-motivated stress definition and a global/regional stress measure combined with an …
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Mechanics and dynamics of living mammalian cytoplasm
… dependent complex moduli of a viscoelastic material has been widely accepted for systems at thermal equilibrium. However, cytoplasm of a living cell operates far from equilibrium and thus, the applicability of passive microrheology in living cells is often questioned. Active microrheology …
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