Composite flywheels with rim and hub
TL;DR: In this paper, a flywheel of high energy density by increasing both rotating speed and moment of inertia of the disc is investigated, and the optimal shape of the flywheel is numerically sought by varying the dimensions of the hub and the rim.
About: This article is published in International Journal of Mechanical Sciences.The article was published on 1983-01-01. It has received 9 citations till now. The article focuses on the topics: Flywheel.
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TL;DR: In this paper, an analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is summarized.
Abstract: In this study an attempt is made to put into perspective the problem of a rotating disk, be it a single disk or a number of concentric disks forming a unit. An analytical model capable of performing an elastic stress analysis for single/multiple, annular/solid, anisotropic/isotropic disk systems, subjected to pressure surface tractions, body forces (in the form of temperature-changes and rotation fields) and interfacial misfits is summarized. Results of an extensive parametric study are presented to clearly define the key design variables and their associated influence. In general the important parameters were identified as misfit, mean radius, thickness, material property and/or load gradation, and speed; all of which must be simultaneously optimized to achieve the ‘best’ and most reliable design. Also, the important issue of defining proper performance/merit indices (based on the specific stored energy), in the presence of multiaxiality and material anisotropy is addressed. These merit indices are then utilized to discuss the difference between flywheels made from PMC and TMC materials with either an annular or solid geometry. Finally two major aspects of failure analysis, that is the static and cyclic limit (burst) speeds are addressed. In the case of static limit loads, a lower (first fracture) bound for disks with constant thickness is presented. The results (interaction diagrams) are displayed graphically in designer friendly format. For the case of fatigue, a representative fatigue/life master curve is illustrated in which the normalized limit speed versus number of applied cycles is given for a cladded TMC disk application.
54 citations
TL;DR: In this article, a composite flywheel is designed using a composite of low density and high strength for the center portion, with constant stress as the design criteria and a constant thickness outer portion using a high density composite attached at the boundary of the constant stress disk.
Abstract: A composite flywheel is designed using a composite of low density and high strength for the center portion, with constant stress as the design criteria and a constant thickness outer portion using a high density composite attached at the boundary of the constant stress disk. This combination produces the maximum energy density for a flywheel energy storage system. 6 references.
16 citations
TL;DR: In this article, two disk thicknesses were examined: uniform thickness and varied thickness, becoming thinner with distance from the disk center, and the maximum burst tip tip speed was calculated as 1376m/s for the uniform thickness no-bundles-added model and 1797 m/s with varied thickness No-Bundles added model.
13 citations
13 May 2014
TL;DR: In this article, the authors propose a liquid-based flywheel where the moment of inertia is engineered to be a function of speed by appropriately sizing and shaping the liquid's spinning container.
Abstract: For a rural microgrid requiring simplicity and robustness, a flywheel-generator combination directly coupled to the grid offers both energy storage and inherent stability. The tradeoff of using a directly-coupled flywheel with a constant moment of inertia is that the amount of energy extractable from within the narrow band of synchronous speeds is limited. Furthermore, a large amount of unusable energy remains within the flywheel below the grid's minimum frequency. By using a flywheel with a variable moment of inertia, although the nett energy may be less, the extractability can be increased by straightforward design. This paper presents the concept of a liquid-based flywheel where the moment of inertia is engineered to be a function of speed by appropriately sizing and shaping the liquid's spinning container.
7 citations
TL;DR: In this article, the natural frequencies of inplane vibration of polar orthotropic annular plates with parabolically varying thickness have been analyzed using a semianalytical method, where the radial and tangential displacements are expanded in the circumferential direction as a Fourier series and the radial behaviour is modelled by finite elements.
4 citations
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TL;DR: In this article, a phenomenological fracture condition for ortho tropic brittle materials is proposed, which can account for widely differing compressive and tensile strengths in ortho tropical brittle materials.
Abstract: A phenomenological fracture condition is proposed for ortho tropic brittle materials. It contains nine material parameters and can account for widely differing compressive and tensile strengths in ...
694 citations
TL;DR: In this paper, the optimal shape of flywheels is determined as a function of the degree of anisotropy of the flywheel's anisotropic components. But the optimal shapes of flywheel components are not restricted to the case of equal reinforcement in the radial and circumferential directions.
Abstract: An analysis is given of the kinetic energy storage capacity of anisotropic flywheels. Using a uniform strain failure criteria, the optimal shapes of flywheels are determined as a function of the degree of anisotropy. Within this spectrum of shapes, practical design considerations are shown to favor the case where there is equal reinforcement in the radial and circumferential directions. Comparisons are made between the present solid-wheel-type design and the ring design and also between candidate materials.
28 citations
01 Nov 1976
TL;DR: An analysis of the kinetic energy storage capacity of anisotropic flywheels is given in this article, where the optimal shapes of flywheel are determined as a function of the degree of an isotropy within this spectrum of shapes, practical design considerations are shown to favor the case where there is equal reinforcement in the radial and circumferential directions.
Abstract: An analysis is given of the kinetic energy storage capacity of anisotropic flywheels Using a uniform strain failure criteria, the optimal shapes of flywheels are determined as a function of the degree of anisotropy Within this spectrum of shapes, practical design considerations are shown to favor the case where there is equal reinforcement in the radial and circumferential directions Comparisons are made between the present solid-wheel-type design and the ring design and also between candidate materials
27 citations
TL;DR: In this paper, the distribution of residual stresses in the discs were analyzed by considering anisotropic shrinkage of impregnated roving during the setting and cooling processes, and it was made possible to predict the critical value of the inner to outer radius ratio less than which the crack did not occur in molded discs.
Abstract: Discs of uniform thickness with a hole at the center were molded by winding the prepregs of glass fiber roving with polyester resin. A circumferential crack occurred in the disc when the inner to outer radius ratio of the disc became larger than a certain critical value. It was found that this crack was due to residual stresses in the disc developed in molding process. The distribution of residual stresses in the discs were analysed by considering anisotropic shrinkage of impregnated roving during the setting and cooling processes. These theoretical results approximately coincided with experimental results. From these results, it was made possible to predict the critical value of the inner to outer radius ratio less than which the crack did not occur in molded discs. It was also shown that the autofrettaged discs with arbitrary inner to outer radius ratio could be molded by anisotropic shrinkage of resin impregnated roving.
4 citations
TL;DR: In this paper, the strength of the rotating discs of uniform thickness which have been molded out of glass fibers and polyester resins by the filament winding method was investigated theoretically and experimentally, and it was shown that there is a good prospect of realizing high speed rotating discs by using fiber reinforced materials.
Abstract: This paper presents the strength of the circular rotating discs of uniform thickness which have been molded out of glass fibers and polyester resins by the filament winding method. The molding process is characterized by the multilayered winding method to reduce the residual stresses developed due to the anisotropic shrinkage of the composite. The stress distribution and the failure criterion of the rotating discs are investigated theoretically and experimentally. It is shown that there is a good prospect of realizing high speed rotating discs by using fiber reinforced materials.
3 citations