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Full-Text Articles in Engineering
The Effects Of Bolt Pretension, In-Plane Eccentricity, And Friction On The Ductility Of Block Shear Connections, Kevin M. Zmetra
The Effects Of Bolt Pretension, In-Plane Eccentricity, And Friction On The Ductility Of Block Shear Connections, Kevin M. Zmetra
Master's Theses
Block shear is a complex failure mechanism in bolted and welded steel components such as gusset plates, webs of coped beams, angles and tees. It presumes a combination of tension rupture and shear yield. Multiple variables affect the block shear capacity and ductility of a connection. This study investigates the effects of bolt pretension, connection eccentricity and friction force transfer through a series of destructive experiments followed by refined finite element simulation. Clamping forces create a complex triaxial stress field compounded by the stress concentration at the bolt holes. In-plane load eccentricity with respect to the centerline of the connection …
High Speed Atomic Force Microscopy Techniques For The Efficient Study Of Nanotribology, James L. Bosse
High Speed Atomic Force Microscopy Techniques For The Efficient Study Of Nanotribology, James L. Bosse
Master's Theses
As mechanical devices scale down to micro/nano length scales, it is crucial to understand friction and wear at the nanoscale (nanotribology) especially at technically relevant sliding velocities. Accordingly, three novel techniques have been developed to study nanotribology, leveraging recent advances in high speed AFM. The first method utilizes high line-scanning rates coupled with sinusoidal scanning along the AFM fast scan axis, enabling rapid friction measurements as a function of velocity up to 20 mm/sec. The second method rapidly acquires friction versus force curves through disabling the feedback loop during scanning and relating the resulting lateral data with the correspondingly varying …
The Effect Of Magnetic Bearing On The Vibration And Friction Of A Wind Turbine, Mark Ryan Vorwaller
The Effect Of Magnetic Bearing On The Vibration And Friction Of A Wind Turbine, Mark Ryan Vorwaller
Electronic Theses and Dissertations
Demands for sustainable energy have resulted in increased interest in wind turbines. Thus, despite widespread economic difficulties, global installed wind power increased by over 20% in 2011 alone. Recently, magnetic bearing technology has been proposed to improve wind turbine performance by mitigating vibration and reducing frictional losses. While magnetic bearing has been shown to reduce friction in other applications, little data has been presented to establish its effect on vibration and friction in wind turbines. Accordingly, this study provides a functional method for experimentally evaluating the effect of a magnetic bearing on the vibration and efficiency characteristics of a wind …