In recent years, tuned liquid dampers (TLD) have proved a successful control strategy for reducing structural vibrations. The present study focuses on the frustum-conical TLD as an alternative to the traditional cylin...
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作者：
Vala, JUniv Technol Brno
Fac Civil Engn Dept Math & Descript Geometry Brno 66237 Czech Republic
The paper deals with the homogenization of variational formulations of non-linear systems of PDEs with periodically oscillating coefficients, occur-ring in engineering mechanics, whose microstructure can include holes...
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The paper deals with the homogenization of variational formulations of non-linear systems of PDEs with periodically oscillating coefficients, occur-ring in engineering mechanics, whose microstructure can include holes of complicated shapes and parts of different dimensions. The first section discusses some approaches to the mathematical formulation of physical and engineeringproblems where the advanced analysis of microstructural properties is needed to obtain numerical results of non-negligible validity;in most cases some kind of homogenization cannot be avoided. One of the most effective approaches, involving certain compensated compactness phenomenon, is based on the idea of the two-scale convergence, whose definition and basic properties (with respect to Radon measures) are presented in the second section. The last section is devoted to the microstructural and macrostructural formulation of a model elliptic problem;it is demonstrated how the notion of the two-scale homogenization explains and simplifies the complicated form of the macroscopic limit equation, thanks to the addition of a new microscopic hidden variable. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.
作者：
Vala, JUniv Technol Brno
Fac Civil Engn Dept Math & Descript Geometry Brno 66237 Czech Republic
The paper deals with the homogenization of variational formulations of non-linear systems of PDEs with periodically oscillating coefficients, occur-ring in engineering mechanics, whose microstructure can include holes...
详细信息
The paper deals with the homogenization of variational formulations of non-linear systems of PDEs with periodically oscillating coefficients, occur-ring in engineering mechanics, whose microstructure can include holes of complicated shapes and parts of different dimensions. The first section discusses some approaches to the mathematical formulation of physical and engineeringproblems where the advanced analysis of microstructural properties is needed to obtain numerical results of non-negligible validity;in most cases some kind of homogenization cannot be avoided. One of the most effective approaches, involving certain compensated compactness phenomenon, is based on the idea of the two-scale convergence, whose definition and basic properties (with respect to Radon measures) are presented in the second section. The last section is devoted to the microstructural and macrostructural formulation of a model elliptic problem;it is demonstrated how the notion of the two-scale homogenization explains and simplifies the complicated form of the macroscopic limit equation, thanks to the addition of a new microscopic hidden variable. (C) 2002 IMACS. Published by Elsevier Science B.V. All rights reserved.
smart materials and structural systems are increasingly attracting attention from the engineering community because of their importance in current and future high performance structural applications. As these new stru...
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smart materials and structural systems are increasingly attracting attention from the engineering community because of their importance in current and future high performance structural applications. As these new structural systems emerge, there is an important need to have capabilities that can be employed for assessing their performance with reference to the primary functional requirement of structural integrity and control robustness as well as reliability. Furthermore, it is desirable to establish adequate performance metrics (which account for inherent or environmental uncertainties) that can be used as a quantitative basis for the comparative evaluation of various design options or for assessing the state of such systems that are already in service. In this study, two measures that can be used for probabilistic characterization and assessment of the performance of actively controlled smart structures are developed. The framework is based on the use of the probabilistic finite element strategy for modelling the parent (host) structure as well as the piezoelectric materials that are employed for sensing and actuation in the assembled system. The uncertainties inherent in the parent structure and the piezoelectric materials are propagated through the probabilistic finite element model. This enables rational and realistic characterization of the performance measures. The probabilistic models are based on the use of advanced reliability analysis algorithms which utilize fast probability integration algorithms that are robust and computationally more efficient than Monte Carlo simulation schemes. To facilitate efficient computation, an adaptive response surface methodology is employed for the approximation of the probabilistic finite element response quantities. Example problems are used to illustrate the robustness and usefulness of the proposed methodology.
smart materials and structural systems are increasingly attracting attention from the engineering community because of their importance in current and future high performance structural applications. As these new stru...
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ISBN:
(纸本)0819431419
smart materials and structural systems are increasingly attracting attention from the engineering community because of their importance in current and future high performance structural applications. As these new structural systems emerge, there is an important need to have capabilities that can be employed for assessing their performance with reference to the primary functional requirement of structural integrity and control robustness as well as reliability. Furthermore, it is desirable to establish adequate performance metrics (which account for inherent or environmental uncertainties) that can be used as a quantitative basis for the comparative evaluation of various design options or for assessing the state of such systems that are already in service. In this study, two measures that can be used for probabilistic characterization and assessment of the performance of actively controlled smart structures are developed. The framework is based on the use of the probabilistic finite element strategy for modelling the parent (host) structure as well as the piezoelectric materials that are employed for sensing and actuation in the assembled system. The uncertainties inherent in the parent structure and the piezoelectric materials are propagated through the probabilistic finite element model. This enables rational and realistic characterisation of the performance measures. The probabilistic models are based on the use of advanced reliability analysis algorithms which utilize fast probability integration algorithms that are robust and computationally more efficient than Monte Carlo simulation schemes. To facilitate efficient computation, an adaptive response surface methodology is employed for the approximation of the probabilistic finite element response quantities. Example problems are used to illustrate the robustness and usefulness of the proposed, methodology.
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