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 “"Hertzian Contact"”.
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Contact area between cylinders in rolling contact
The contact area between two rollers or cylinders was investigated both theoretically and experimentally. The theoretical investigation was based on Hertzian theory, while the experimental method used was based on the measurement of contact resistances. The variables in the investigation were the …
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Investigation of the finite element method for computing wheel/rail contact forces in steady curving
… include such nonlinear effects as two-point contact, creep force saturation, and rail flexibility. The usual approximation concerning the contact geometry is that the Iocalized wheel and rail curvatures at the center of the contact patch are constant throughout the contact patch. This …
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Residual stresses due to grinding
… yield thermal stresses. An extension of the Hertzian contact theory yields mechanical stresses, which are then superimposed on the thermal stresses. Approximate plasticity corrections are used to approximate the deformation as the grinding wheel passes over the workpiece. Subsurface results …
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Surface mechanics of polyacrylamide hydrogels following wear
… computed from the region of the curves fitting a Hertzian contact regime. The results show that the surfaces are stiffer directly after wear. These changes are recoverable, and after several days of resting underwater, the hydrogel’s surface stiffness characteristics return to similar values as …
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Effects of nanoscale film thickness on apparent stiffness of and cell-mediated strains in polymers
… that require multiaxial loading conditions. The Hertzian contact models developed for linear elastic materials of semi-infinite thickness fail to accurately predict the elastic modulus E for these compliant materials. This makes it necessary to understand the evolution of stress and strain fields …
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Kinematic alignment of precision robotic elements in factory environments
… along with traditional design parameters such as Hertzian contact stress and preload. To test out the application of kinematic couplings to detrimental environments, two separate case studies were performed. The first case study consists of a small scale metrology device used to calibrate the home …
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Experimental investigation of the effect of spin on traction in elastohydrodynamically lubricated contacts
… three driving and two driven, at maximum Hertzian contact pressures of 300 KSI, 333 KSI, 400 KSI, and 450 KSI. The angle between the axis of the driven ball and the normal to the plane of contact was varied from 40° to 50° and data were taken to determine the relation between coefficient …
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Dynamic Friction Characterization of Tripod Constant Velocity (Cv) Joints: Experiments, Analysis and Modeling
… through FE analysis. Also, the validity of Hertzian contact analysis in a CV joint was assessed using the FE method, and found that the Hertzian solutions are practically applicable under low contacting load. These contact results were incorporated in the friction model. Subsequently the …
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Wave tailoring in elastic and elastoplastic granular systems
… lattices. We start by developing a unified contact law for elasto-plastic granules of distinct sizes and material properties using quasistatic finite element simulations. Extensive numerical studies are then conducted on the dynamics of elastic and elasto-plastic granular chains under a wide …
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Shock compression and dynamic fragmentation of geological materials
… was analysed using geometric grain models and Hertzian contact theory. The shock Hugoniot of each ma- terial was measured though a series of plate impact experiments using a light gas gun. The experiments focused on the stress region of interest for blast mining, 0 to 12 GPa. The, fully dense, …
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Modeling of contact between liner finish and piston ring in internal combustion engines based on 3D measured surface
… when piston is at low speed and there is direct contact between rings and liners. This work focuses on prediction of contact between piston ring and liner finish based on 3D measured surface and different methods are compared. In previous twin-land oil control ring (TLOCR) deterministic model, …
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Material transfer associated with the contact between polymer and silicon surfaces
Material transfer due to the contact of surfaces is encountered in a wide variety of engineering applications. One of these is the backside contamination of silicon wafers due to contact with polymer vacuum chucks during spin coating. The present research investigates material transfer associated …
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Discrete Element Modeling of Railway Ballast for Studying Railroad Tamping Operation
… of ballast parameters, such as inter-particle contact force laws, ballast material properties, and selection of particle shape are represented in detail in the model. Finally, a complete tamping simulation model is constructed with high degree of adjustability to allow control of all process …
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The development of rail-head acoustic roughness
… used as the input to a two-dimensional rolling contact and wear model. The possibility of multiple wear mechanisms arising from stress concentrations is considered by using a wear coefficient that can vary with the conditions at each point in the contact. The contact model is based on a …
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Complex Mechanical Properties of Steel
… phenomenon especially in bearings due to the Hertzian contact which takes place. A model has been developed that is able to quantify the residual stress distribution, under the raceway of martensitic ball bearings, using the running conditions. It is evident that a well–formulated neural …
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The Sliding Friction of Bonded Solid Lubricants
… theories of friction for metals in sliding contact and the friction theory applied to solid film lubrication are reviewed. A section is also included on Herzian contact theory and its application to solid films. A screening test is described for 12 BSLs applied to commercial components. This …
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Response of grooved composite laminates to out-of-plane contact loading via numerical models
… of grooved composite laminates to out-of-plane contact loading is examined using numerical modeling through the consideration of contact pressure and stresses within the laminate, with particular focus on the area local to the groove. Finite element analysis is employed via ABAQUS, a commercial …
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Accurate Wheel-rail Dynamic Measurement using a Scaled Roller Rig
… on creep or traction forces. The wheel-rail contact forces, also referred to as traction forces, are critical for all aspects of rail dynamics. These forces are quite complex and they have been the subject of several decades of research, both in experiments and modeling. The primary intent of …
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Adaptation Of The Biodent For Spherical Microindentation To Determine Elastic Modulus In Small Rodent Bones
… indentation lies in its operation under Hertzian contact in a non-destructive manner, which opens its potential for future viscoelastic and dynamic studies.</p> <p>In the current study, we tested whether a BioDent<sup>TM</sup>, Reference Point Indentation (RPI) device, could be …
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