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.
Results
Showing 1 to 20 of 20 for “"static friction"”.
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Fault damage zones and friction: insights from shallow Japan Trench drill core
… slip behavior. Shear displacement on faults is a frictional phenomenon in the sense that slip begins when the ratio of shear to normal stress surpasses the static friction coefficient (μs). Thus, earthquakes and the associated patterns of slip are controlled by the frictional properties of faults. …
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Ultrahigh vacuum studies of the boundary lubrication of metals
… species as a function of coverage. The friction behavior of clean Cu(111) surfaces was characterized by stick-slip sliding behavior and high static friction coefficients.
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Softmatter tribology: Understanding the microstructure to property relationships of hydrogel-like materials
… i.e. a load-bearing tissue that maintains low friction and wear. In fact, recent studies have shown that the cartilage’s articulating surface comprises of a network of highly hydrated mucins, polysaccharides, glycoproteins, and phospholipids, which play a key role in maintaining low friction in …
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Scaling a Prismatic Revolute Joint (Pr) Manipulator Using Similitude and Buckingham Pi Techniques
… and gearmotors that exhibit internal nonlinear friction. Similitude methods were used to develop a scaleable two degree-of-freedom trajectory planner from a third order polynomial. Scaling laws were developed from Buckingham's Pi theorem to facilitate the selection process of gearmotors. …
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Haptic simulation of naturally occuring textures and soil properties
… controlled manipulator. A method for sensing friction properties of rigid, textured surfaces and using the data collected to drive a realistic haptic texture simulation is presented. Static friction coefficients and surface height deviations a e sensed by directly stroking the surface under …
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Surface self-compensated hydrostatic bearings
… known in the machine tool industry that hydrostatic bearing technology has several unique advantages over rolling element bearings. The thin fluid film between the bearing pads and the rail provides virtually infinite motion resolution due to lack of static friction, very low straightness …
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Modeling and control of antilock braking systems utilizing dynamic friction tire model
… the utilization and formulation of a new dynamic friction tire model for the development and testing of designed controller. Due to complex mechanics of tires, the dynamic friction tire model is significantly more realistic than that of commonly used static friction tire model. A detailed …
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Dynamic Friction Characterization of Tripod Constant Velocity (Cv) Joints: Experiments, Analysis and Modeling
… thesis is to develop a physics-based internal friction model of tripod CV joints that can be readily applied during new vehicle development. This model will replace current practices of using empirical fixed friction coefficient values. In order to achieve this goal, a prototype …
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The Influence of Root Geometry on Soil Cohesion and Anchoring Ability through Geologic Time
… contributions of root weight, sediment weight, static friction, and shear strength. This analysis revealed a strong dependence on the span, surface area, and volume of the root system, which were used to normalize values across different geometries. The Calamophyton model required the greatest …
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The role of frictional heating in the development of catastrophic landslides
… in the slip zone due to the heat produced by friction, leading to thermoplastic collapse of the soil skeleton and subsequent increase of pore water pressure. This in turn drastically decreases the resistance to motion and allows the overlying mass to move downslope ever more …
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Simulation of urea particle flow using DEM for dry fertilizer spreading optimization
… parameter set consisted of a particle-particle static friction coefficient of 0.27 and a rolling friction coefficient of 0.11. With this set, the DEM model predicted angle of repose and bulk density with percent relative errors of 10.02% and 7.50%, respectively. The calibrated model was then …
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Direct Sensitivity Analysis of Spatial Multibody Systems with Joint Friction
… systems. Multibody formulations with joint friction were developed in the recent years and these systems have to be modeled by highly non-linear differential algebraic equations (DAEs) that are difficult to solve using numerical methods. The sensitivity analysis of such systems and the …
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Controllable Adhesion In A Bio-Inspired Film-Terminated Fibrillar Surface
… has up to 20 times larger adhesion hysteresis. Friction experiments show that in the collapsed state there is no static friction peak and that even in sliding friction, which is not enhanced for the adhesive state over the control samples (flat, unstructured PDMS), the collapsed state exhibits …
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Numerical simulation of an optimal channel cross-section
… of conditions: (1) the submerged coefficient of static friction of the channel bed material, (2) lift-to drag ratio, (3) grain size of the bed material, (4) water discharge, and (5) longitudinal slope of the channel. The term optimal stable channel refers to a channel capable of transporting …
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Discrete element method simulation of wheat bulk density
… parameters, the wheat-to-wheat coefficient of static friction and wheat-to-wheat rolling friction had the greatest influence on simulated bulk density. Wheat bulk density as affected by drop height and percentage composition of the three kernel fractions can be simulated accurately using either …
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The Mechanics of Active Faulting and Mountain Building
… at Bam, most of the fault zone must remain frictionally locked. I also find that, to explain the postseismic InSAR measurements and the long-term growth of topography at Bam, there must be either an E-W deviatoric stress of 2-10 MPa acting across the fault zone, or some component of fabric …
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Dynamics and Statics of Three-Phase Contact Line
… wetting is governed by the dynamic and static behaviors of the three-phase contact line. Therefore, a deep insight into the dynamics and statics of three-phase contact line at nanoscale is necessary for the technological advancement in nanotechnology and nanoscience. This dissertation …
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Bio-inspired robotic control in underactuation: principles for energy efficacy, dynamic compliance interactions and adaptability.
… accurate modelling or prediction of nonlinear friction forces is a nontrivial whilst challenging task. Frictional instabilities are typically required to be eliminated or compensated through efficiently designed controllers. In this work, a prediction and analysis framework is designed for the …
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Discrete element method based scale-up model for material synthesis using ball milling
… planetary, and attritor mills. The rolling and static friction coefficients are determined experimentally. Computations predict a quasi- steady rate of energy dissipation, Ed, for each experimental configuration. It is proposed that the milling dose defined as a product of Ed and milling time, …
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Modeling of the great earthquake seismic cycles
… transient viscous rheology, and rate-and-state friction. It generates spontaneous earthquake sequences, and, by using an adaptive time-step algorithm, recreates the deformation process as observed naturally over single and multiple seismic cycles. The model is thoroughly tested by comparing …