Structural vibrations caused by a flowing fluid. Whenever a structure is exposed to a flowing fluid,…

Flow-induced vibration

(Vol. 1, part of 2 vols set) Size: 22x14cm., Contents: Chapter I. Tension and Compression within the Elastic Limit II. Analysis of Stress and Strain III. Bending Moment and Shearing Force IV. Stresses in Laterally Loaded Symmetrical beams V. Deflection of Laterally Loaded Symmetrical Beams VI. Statically Indeterminate Problems in Bending VII. Symmetrical Beams of Variable Cross Section-Beams of Two Materials VIII. Bending of Beams in a plane which is not a Plane of Symmetry IX. Combined Bending and Axial Load Theory of Columns X. Torsion and Combined Bending and Torsion XI. Strain Energy and Impact XII. Curved Bars Appendix A: Moments of Inertia of Plane Areas Appendix B. Tables of Structural Shapes Author Index Subject Index. ISBN:8123910304 xiv+442 Yr. of Pub.reprint 2004Paper Back

Strength of materials ..

This study investigates the performance of a double-beam piezo-magneto-elastic wind energy harvester (DBPME-WEH) when exhibiting a galloping-based energy harvesting regime under wind excitation. The DBPME-WEH comprises two piezoelectric beams, each of which supports a prism bluff body embedded with a magnet at the tip. The magnets are oriented to repulse each other to introduce a bistable nonlinearity. Wind tunnel tests were conducted to compare performances of the DBPME-WEH and a double-beam piezoelectric wind energy harvester (DBP-WEH) that does not comprise the magnet-induced nonlinearity. The results reveal that compared to the DBP-WEH, the critical wind speed to activate the galloping vibration of DBPME-WEH can be reduced up to 41.9%. Thus, the results corroborate the significant performance enhancement by the DBPME-WEH. It can also be found that the distance of the two magnets affects the performance and the distance that achieves the weakly bistable nonlinearity is beneficial to energy harvesting in reducing the critical wind speed and improving the output voltage.

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A double-beam piezo-magneto-elastic wind energy harvester for improving the galloping-based energy harvesting

Experimental investigation on the efficiency of circular cylinder-based wind energy harvester with different rod-shaped attachments

This study evaluated the performance of twin adjacent galloping-based piezoelectric wind energy harvesters based on mutual interference. The relative position between the twin harvesters is crucial to their energy generation efficiency. A series of wind tunnel tests were conducted to test energy generation of the two harvesters in tandem or staggered arrangements. The optimal relative position, a streamwise center to center spacing of 1.2B (B is the width of the harvester's square prism) and a transverse center to center spacing of 1.0B, was identified. The total output power of the two harvesters placed in the optimal relative position is up to 2.2 times that of two isolated harvesters. The output power is also much larger than that of the harvesters in tandem arrangements that have been widely tested in previous studies. Therefore, it is recommended to position two adjacent harvesters in optimal relative position(s) to deliver an optimal power output.

Performance evaluation of twin piezoelectric wind energy harvesters under mutual interference

http://web.mit.edu/jociek/www/Kluger_JFS_2013.pdf

Shape optimization of a blunt body Vibro-wind galloping oscillator

https://sandlab.mit.edu/Papers/15_JSV.pdf

Robust energy harvesting from walking vibrations by means of nonlinear cantilever beams

A symbiotic approach to the design of offshore wind turbines with other energy harvesting systems

In the present work, we describe a nonlinear stiffening load cell with high resolution (the ability to detect 1% changes in the force) that can function over a large force range (5 orders of magnitude), and exhibit minimal hysteresis and intrinsic geometric protection from force overload. The stiffening nature of the load cell causes its deflection and strain to be very sensitive to small forces and less sensitive to large forces. High stiffness at high forces prevents the load cell from over-straining. We physically implement the nonlinear springs with cantilever beams that increasingly contact rigid surfaces with carefully chosen curvatures as more force is applied. We analytically describe the performance of the load cell as a function of its geometric and material parameters. We also describe a method for manufacturing the mechanical component of the load cell out of one monolithic part, which decreases hysteresis and assembly costs. We experimentally verify the theory for two load cells with two different sets of parameters.

/pdf/a-high-resolution-and-large-force-range-load-cell-by-means-1qybcwhn9n.pdf

A high-resolution and large force-range load cell by means of nonlinear cantilever beams

This paper investigates the potential for combining energy harvesting and damping systems as a means for stabilizing floating offshore wind turbines while increasing the total amount of power generated. Ever taller wind turbine towers are needed to accommodate ever larger rotor diameters, which for floating offshore turbines would normally necessitate ever deeper draft marine structures, such as spar buoys, to provide required stability. Damping structures, some of which have energy harvesting mechanisms, have been proposed and shown to be effective for floating turbines, but face the problem of transforming low frequency variable amplitude motion into steady power output. Here the idea of a piston pump in the form of a moving float mechanism is introduced to pump water out of a temporary storage chamber located at the bottom of a floating platform structure. Water flowing down the floating structure through a power turbine empties into the chamber. The entire structure might ideally now only depend on a single anchor line projecting from its center bottom to the seafloor, thereby also reducing the cost of moorings.

Jocelyn Maxine Kluger

Papers

Shape optimization of a blunt body Vibro-wind galloping oscillator

Robust energy harvesting from walking vibrations by means of nonlinear cantilever beams

A symbiotic approach to the design of offshore wind turbines with other energy harvesting systems

A high-resolution and large force-range load cell by means of nonlinear cantilever beams

Energy Harvesting and Storage System Stabilized Offshore Wind Turbines