Design of Steel-Composite Multirim Cylindrical Flywheels Manufactured by Winding with High Tensioning and <Emphasis Type="Italic">in situ</Emphasis> Curing. 1. Basic Relations

The possibility of using force winding coupled with in situ curing to increase the energy storage capacity of hybrid steel-composite cylindrical flywheels is estimated and analyzed. Relations describing the rotational, thermal, and winding stresses are considered and discussed. These relations are used for a numerical analysis of the stress state and energy capacity of hybrid flywheels in the second part of the paper.__________Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 41, No. 2, pp. 203–224, March–April, 2005.     

Spin-tests of composite flywheels. A review

Spin-test results are given for two types of composite flywheels, namely, molded disks and rim-type flywheels with chordwise wrapping. The models differend in form, size, and material. Dynamic problems associated with flywheel spinning-up, ultimate peripheral speeds, and the limiting energy-storing capacities are described. Results are also given for full-scale flywheel tests. Dynamic problems were shown to be the governing factors for rim-type flywheels.Translated from Mekhanika Kompozitnykh Materialov, Vol. 33, No. 4, pp. 505–526, July–August, 1997.     

Energy capacity of rotating composite designs (review)

Conclusions Theoretical investigations that have been performed and experimental confirmation on models have conclusively confirmed the high efficiency of composite flywheels. The most promising design at the present time is the chorded flywheel, especially for pulse energy sources. It can be assumed that the flexibility of the chords makes it possible to achieve a balanced design more simply. Problems of balancing, as, in general, the dynamics of energy-storing rotating composite components, however, will be the subject of further independent research.Translated from Mekhanika Kompozitnykh Materialov, No. 1, pp. 65–78, January–February, 1986.     

Mathematical modelling of a hydraulic accumulator for hydraulic hybrid drives

ABSTRACT

Hydraulic accumulators are used as energy storages in a wide area of applications. In particular, in automotive hybrid drive-trains, this type of energy storage is an interesting alternative to today’s common strategies like chemical batteries or flywheels. This article deals with the mathematical modelling of a hydraulic accumulator for passenger vehicles, which comprises a carbon fibre reinforced plastic (CFRP) body and aluminium piston. The thermodynamical behaviour of the oil and gas as well as the interaction with the CFRP body is investigated in detail. Starting from a complex model, two models of reduced complexity are derived. The validation of these models with measurement data from a test drive with a prototype series hydraulic hybrid drive-train proves their high accuracy.     

Some Aspects of Designing Multirim Composite Flywheels

Approximate solutions are given for stresses in a flexible cylindrical interlayer connecting concentric, rigid, cylindrical rims subjected to three loading cases: (i) rotation about the axis of symmetry; (ii) in-plane translation of the rims relative to each other; (iii) out-of-plane rotation of the rims relative to each other. The solutions are important for the multiple filament-wound composite rims used in energy storage flywheels, where the elastomeric interlayer idea has been proposed as a means of preventing high radial tensile stresses, which would otherwise break down the rims at less than optimal speeds. The compliances associated with the second and third loading cases are also given, establishing a simple means of analysis of the critical vibration frequencies of multirim flywheel rotors.     

Dissipativity theory for discontinuous dynamical systems: Basic input, state, and output properties, and finite-time stability of feedback interconnections

In this paper, we develop dissipativity theory for discontinuous dynamical systems. Specifically, using set-valued supply rate maps and set-valued connective supply rate maps consisting of locally Lebesgue integrable supply rates and connective supply rates, respectively, and set-valued storage maps consisting of piecewise continuous storage functions, dissipativity properties for discontinuous dynamical systems are presented. Furthermore, extended Kalman–Yakubovich–Popov set-valued conditions, in terms of the discontinuous system dynamics, characterizing dissipativity via generalized Clarke gradients and locally Lipschitz continuous storage functions are derived. Finally, these results are used to develop feedback interconnection stability results for discontinuous dynamical systems by appropriately combining the set-valued storage maps for the forward and feedback systems.     

Destruction of polyethylene-oxide films during storage

Conclusion In lengthy storage of PEO films the amorphous part of the material is subjected most to destruction under the effect of environmental factors; consequently, films with a higher degree of crystallinity are more suitable for storage. The resistance of individual sections of film to environmental factors is a random variable, and the nature of the encountered patterns of destruction can therefore be reproduced with the aid probabilistic models.Translated from Mekhanika Kompozitnykh Materialov, Vol. 30, No. 4, pp. 464–470, July–August, 1994.     

基于主成分分析的新能源储能企业技术创新能力研究

基于科技创新投入、产出、支撑和转化等四个影响因素,构建新能源储能企业科技创新能力评价模型,并运用主成分分析法和聚类分析法,对我国主要新能源储能企业的科技创新能力进行分析和评价．分析表明,我国新能源储能企业科技创新的能力主要取决于经费投入和科研能力两大因素．新能源企业科技创新的研发经费投入、科研人员配备、科研成果等方面,与国外企业相比差距大,科技创新能力亟待提高．     

Optimal design of reinforced-plastic chord flywheels under reliability limitations

Conclusions The proposed method makes it possible to accomplish optimal design of a CF according to the condition of providing a maximum energy-storing capacity with consideration of the random character of the strength and deformation properties of the plastic being used and the geometry of the composition of the system. In this case, the problem of optimal design reduces to a nonlinear programming problem, where the random values of the objective function and limitations are calculated on the basis of the Monte Carlo method. The requirement of fulfilling the prescribed level of reliability of the CF is the condition of optimal design, which makes it possible to take into account the variation of the load-bearing capacity of the structure, variation of the energy-storing capacity, and conditions of the planned purpose. The effect of the structural parameters was analyzed for the example of the optimal design of a FGRP CF and the interrelation and difference of the stochastic and deterministic solutions was shown. The investigations can be useful in the practice of using effective reinforced plastics in the production of mechanical energy storages.Translated from Mekhanika Kompozitnykh Materialov, No. 5, pp. 908–914, September–October, 1988.     

Carrying capacity of thick-walled glass-reinforced plastic rings operating under pressure

Experimental data are presented on the carrying capacity and deformability of thick-walled rings made of unidirectional and two-way glass-reinforced plastic subjected to external and internal pressure. A limitation on the carrying capacity of the rings with increase in relative thickness is noted; an explanation of this effect is offered.Institute of Polymer Mechanics, Academy of Sciences of the Latvian SSR, Riga. Translated from Mekhanika Polimerov, No. 6, pp. 1130–1132, November–December, 1971.     

Effect of extended storage on the mechanical properties of reinforced plastics

The effect of storage time (6–10 years) on the mechanical properties of KAST-V glass laminate, textolite, and SVAM glass-reinforced plastic has been experimentally investigated.Moscow Lomonosov State University. Translated from Mekhanika Polimerov, No. 3, pp. 556–558, May–June, 1969.     

Finite-volume corrections to magnetization in the spin-glass phase of the Derrida model

We consider the random energy model, where in the spin-glass phase, magnetization falls off exponentially as the volume increases. This magnetization corresponds to the probability of correct decoding in the case where the information transmission rate exceeds the channel capacity.Translated from Theoreticheskaya i Matematicheskaya Fizika, Vol. 109, No. 3, pp. 422–426, December, 1996.     

Variational problem of the theory of Green's potential. II

Necessary and sufficient conditions for the solvability of the problem of the minimum of the Green's energy on condensers are found. A number of properties of extremals are found.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 11, pp. 1475–1480, November, 1990.     

The application of the genetic algorithm to the minimization of potential energy functions

We adapted the genetic algorithm to minimize the AMBER potential energy function. We describe specific recombination and mutation operators for this task. Next we use our algorithm to locate low energy conformation of three polypeptides (AGAGAGAGA, A9, and [Met]-enkephalin) which are probably the global minimum conformations. Our potential energy minima are –94.71, –98.50, and –48.94 kcal/mol respectively. Next, we applied our algorithm to the 46 amino acid protein crambin and located a non-native conformation which had an AMBER potential energy 150 kcal/mol lower than the native conformation. This is not necessarily the global minimum conformation, but it does illustrate problems with the AMBER potential energy function. We believe this occurred because the AMBER potential energy function does not account for hydration.     

Effect of prolonged storage on the mechanical properties of polycarbonates

The effect of storage time (two-four years) on the principal mechanical characteristics of domestic polycarbonate and West German Makrolon has been experimentally investigated.Moscow Lomonosov State University. Translated from Mekhanika Polimerov, No. 6, pp. 1130–1132, November–December, 1970.     

Thermodynamic Potential of a System of Electrons and Phonons in a Disordered Alloy

We obtain a cluster expansion for the two-time retarded Green's functions and the thermodynamic potential of a disordered crystal taking the electron–phonon and electron–electron interactions into account. The electron states of the system are described in the framework of a multiband tight-binding model. The calculations are based on the diagram techniques for the temperature Green's functions. The coherent potential approximation is chosen as a zeroth-order one-site approximation in this cluster expansion method. We show that the contributions from the processes of scattering of elementary excitations on clusters decrease as the number of sites in the cluster increases in accordance with certain small parameters. Analytic estimates of the influence of the electron–phonon interaction on the energy spectrum of electrons of an alloy being ordered are obtained in a one-band model. The applicability of these results to describing the influence of strong electron correlations on the electron structure and properties of alloys of transition metals with narrow energy bands is illustrated with the example of the Fe–Ti alloy.     

An Iterative Global Optimization Algorithm for Potential Energy Minimization

In this paper we propose an algorithm for the minimization of potential energy functions. The new algorithm is based on the differential evolution algorithm of Storn and Price (Journal of Global Optimization, vol. 11, pp. 341–359, 1997). The algorithm is tested on two different potential energy functions. The first function is the Lennard Jones energy function and the second function is the many-body potential energy function of Tersoff (Physics Review B, vol. 37, pp. 6991–7000, 1988; vol. 38, pp. 9902–9905, 1988). The first problem is a pair potential and the second problem is a semi-empirical many-body potential energy function considered for silicon-silicon atomic interactions. The minimum binding energies of up to 30 atoms are reported.Visitor at the Institute for Mathematics and its Applications, University of Minnesota, USA.     

Limit Regimes of Braking of Disc-Type Composite Flywheels Made by Filament Winding

A set of invariants describing the limit regimes of braking disk-type wound composite flywheels is suggested. The limit regime is determined by using a linear failure criterion. It is shown that, for generating short-time impulses of very high power, a set of small identical flywheels is more effective than one large flywheel with an equivalent mass. Particular examples illustrating the theory considered are discussed.     

Effect of the two-way reinforcing system on the load-carrying capacity of glass-reinforced plastic shells

The load-carrying capacity of thin cylindrical glass-reinforced plastic shells loaded by axial compression and external pressure has been investigated in relation to the characteristics of the two-way reinforcing system. The critical loads are expressed in terms of the characteristics of a parallel-reinforced layer with a coefficient that takes into account the reinforcing system and the shape of the cross section. The relations among the reinforcing layers optimal for the load-carrying capacity are determined and it is shown that independent two-way reinforcing substantially improves the load-carrying capacity of solid shells and shells with a nonload-bearing core.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 6, pp. 1052–1058, November–December, 1969.     

Relationship between the molecular structure and certain mechanical properties of oriented polymers

The correlations between the molecular structure and intermolecular energy and the fatigue and elastic properties of fibers are considered. It is shown that the maximum of these properties corresponds to an optimal value of the intermolecular energy.Leningrad Branch of the All-Union Scientific-Research Institute of Synthetic Fibers. Translated from Mekhanika Polimerov, No. 4, pp. 734–735, July–August, 1969.