The Experts below are selected from a list of 47043 Experts worldwide ranked by ideXlab platform
Dahsin Liu - One of the best experts on this subject based on the ideXlab platform.
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nonlinear analysis of composite plates using interlaminar shear stress Continuity Theory
Composites Engineering, 1993Co-Authors: Chunying Lee, Dahsin LiuAbstract:Abstract An interlaminar shear stress Continuity Theory (ISSCT) presented in a previous study can give excellent results for both the static and vibration analysis of composite beams. This Theory is extended to study composite plates with geometric nonlinearity. The studies are based on nonlinear strain-displacement relations of the von Karman sense. The nonlinear bending and vibration of various composite plates are investigated. The postbuckling behavior of asymmetric plates is also examined. Both closed-form solutions and finite element results are obtained and compared with three-dimensional elasticity solutions. Some important results for composite plates with small aspect ratio and asymmetric lamination are presented. It is concluded that ISSCT is an accurate technique for studying laminated composite plates.
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static and vibration analysis of laminated composite beams with an interlaminar shear stress Continuity Theory
International Journal for Numerical Methods in Engineering, 1992Co-Authors: Chunying Lee, Dahsin LiuAbstract:A finite element method for stress and vibration analysis of laminated composite beams was investigated. The analysis was based on a multilayered Theory presented by Lu and Liu. This Theory accounts for the Continuity of interlaminar shear stress. The principle of minimum potential energy was used in the finite element formulation. The interlaminar shear stress was obtained directly from the constitutive equations. It was verified that the present technique was able to give excellent results for displacements, stresses and vibration frequencies for both thin and thick composite beams. The effects of the number of layers and the number of elements on the convergence were also discussed.
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an interlaminar stress Continuity Theory for laminated composite analysis
Computers & Structures, 1992Co-Authors: Chunying Lee, Dahsin LiuAbstract:Abstract A complete analysis of a new lamination Theory presented in a previous investigation for studying the interlaminar stresses in both thin and thick composite laminates is developed. This Theory is based on a multiple-layer approach. Hermite cubic shape function is used as the interpolation function for composite layer assembly through the thickness direction. Because of the high-order shape function, the Theory can satisfy the Continuity of both interlaminar shear stress and interlaminar normal stress exactly on the composite interface. It then is able to obtain the interlaminar stresses directly from the constitutive equations. In addition, because of the high-order interpolation function, the transverse shear deformation is considered in the Theory. Accordingly, the Theory can be used for both thin and thick composite laminates. In this study, the composite laminates under cylindrical bending studied by Pagano are investigated to verify the new Theory. Closed form solutions agree excellently with the elasticity results. A finite element technique based on the principle of minimum potential energy is also used for numerical analysis. The numerical results also show excellent agreement with the exact solution.
Chunying Lee - One of the best experts on this subject based on the ideXlab platform.
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nonlinear analysis of composite plates using interlaminar shear stress Continuity Theory
Composites Engineering, 1993Co-Authors: Chunying Lee, Dahsin LiuAbstract:Abstract An interlaminar shear stress Continuity Theory (ISSCT) presented in a previous study can give excellent results for both the static and vibration analysis of composite beams. This Theory is extended to study composite plates with geometric nonlinearity. The studies are based on nonlinear strain-displacement relations of the von Karman sense. The nonlinear bending and vibration of various composite plates are investigated. The postbuckling behavior of asymmetric plates is also examined. Both closed-form solutions and finite element results are obtained and compared with three-dimensional elasticity solutions. Some important results for composite plates with small aspect ratio and asymmetric lamination are presented. It is concluded that ISSCT is an accurate technique for studying laminated composite plates.
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static and vibration analysis of laminated composite beams with an interlaminar shear stress Continuity Theory
International Journal for Numerical Methods in Engineering, 1992Co-Authors: Chunying Lee, Dahsin LiuAbstract:A finite element method for stress and vibration analysis of laminated composite beams was investigated. The analysis was based on a multilayered Theory presented by Lu and Liu. This Theory accounts for the Continuity of interlaminar shear stress. The principle of minimum potential energy was used in the finite element formulation. The interlaminar shear stress was obtained directly from the constitutive equations. It was verified that the present technique was able to give excellent results for displacements, stresses and vibration frequencies for both thin and thick composite beams. The effects of the number of layers and the number of elements on the convergence were also discussed.
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an interlaminar stress Continuity Theory for laminated composite analysis
Computers & Structures, 1992Co-Authors: Chunying Lee, Dahsin LiuAbstract:Abstract A complete analysis of a new lamination Theory presented in a previous investigation for studying the interlaminar stresses in both thin and thick composite laminates is developed. This Theory is based on a multiple-layer approach. Hermite cubic shape function is used as the interpolation function for composite layer assembly through the thickness direction. Because of the high-order shape function, the Theory can satisfy the Continuity of both interlaminar shear stress and interlaminar normal stress exactly on the composite interface. It then is able to obtain the interlaminar stresses directly from the constitutive equations. In addition, because of the high-order interpolation function, the transverse shear deformation is considered in the Theory. Accordingly, the Theory can be used for both thin and thick composite laminates. In this study, the composite laminates under cylindrical bending studied by Pagano are investigated to verify the new Theory. Closed form solutions agree excellently with the elasticity results. A finite element technique based on the principle of minimum potential energy is also used for numerical analysis. The numerical results also show excellent agreement with the exact solution.
Patel S. R. - One of the best experts on this subject based on the ideXlab platform.
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On affirmative solution to Michael's acclaimed problem in the Theory of Frechet algebras, with applications to automatic Continuity Theory
2021Co-Authors: Patel S. R.Abstract:In 1952, Michael posed a question about the functional Continuity of commutative Frechet algebras in his memoir, known as Michael problem in the literature. We settle this in the affirmative along with its various equivalent forms, even for the non-commutative case. Indeed, we continue our recent works, and develop two approaches to directly attack these problems. The first approach is to show that the test case for this problem, the Frechet algebra of all entire functions on the Banach space of all bounded complex sequences, is, in fact, a Frechet algebra of all complex formal power series in one indeterminate, if there exists a discontinuous character. In the second approach, the existence of a discontinuous character would allow us to generate other Frechet algebra topology, inequivalent to the usual Frechet algebra topology, by applying the method of Read (he used this method to show that the famous Singer-Wermer conjecture (1955) fails in the Frechet case). In both the approaches, an important tool is a topological version of the (symmetric) tensor algebra over a Banach space; the elementary, but crucial, idea is to express the test algebra as a weighted Frechet symmetric algebra over the Banach space of all absolutely summable complex sequences. Several mathematicians have worked on two problems of Michael since 1952, giving affirmative solutions for special classes of Frechet algebras under various conditions, or discussing various test cases, or discussing various approaches, or discussing various other equivalent forms, or deriving other important automatic Continuity results such as the (non-)uniqueness of the Frechet algebra topology for certain commutative Frechet algebras by alternate, difficult or lengthy methods. We summarize effects of our affirmative solutions on these attempts in addition to giving various new (important) applications in automatic Continuity Theory.Comment: 78 pages; Section 2 is shortened, and Section 3 is improved by giving a direct argument to the Frechet case as well as by adding certain important remark
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On affirmative solution to the prestigious Michael problem in the Theory of Frechet algebras, with applications to automatic Continuity Theory
2020Co-Authors: Patel S. R.Abstract:In 1952, Michael posed a question about the Continuity of characters on commutative Frechet algebras in his memoir, known as Michael problem in the literature. We settle this in the affirmative, even for the non-commutative case. Indeed, we continue our recent works, and develop two approaches to directly attack on the problems. The first approach is to show that the test case for this problem is, in fact, a Frechet algebra of all complex formal power series, if there exists a discontinuous character. Discussions along these lines always skirt the Dales McClure problem (1977), solved affirmatively by Dales, Read and the author in 2010, as well as the Loy problem (1974), solved affirmatively in the Frechet case by the author recently. The elementary, but crucial, idea is that to express the test algebra as a weighted Frechet symmetric algebra over a Banach space. In the second approach, the existence of a discontinuous character would allow us to generate another Frechet algebra topology, inequivalent to the usual Frechet algebra topology, by applying the Read method (he used this method to show that the famous Singer Wermer conjecture (1955) does not hold in the Frechet case, and we have recently constructed two Frechet algebras, admitting countably many mutually inequivalent Frechet algebra topologies by this method; such examples are not known even in the Banach case). In both approaches, an important tool is a topological version of the (symmetric) tensor algebra over a Banach space; we use the notion of tensor product by rows, introduced by Read, in the second approach.....Comment: 72 page
Douglas A Kleiber - One of the best experts on this subject based on the ideXlab platform.
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reconsidering change and Continuity in later life toward an innovation Theory of successful aging
International Journal of Aging & Human Development, 2007Co-Authors: Galit Nimrod, Douglas A KleiberAbstract:This article examines the patterns and meanings of innovation in the activities of a group of retirees with an eye toward understanding the place and value of innovation in the aging process. Starting with a consideration of Continuity Theory, as a perspective that simply describes typical patterns of activity, and activity Theory that prescribes expansion of activities as a key to well-being, this article highlights the characteristics, meanings and perceived benefits of a wide variety of innovative activities. The study utilized in-depth semi-structured interviews with a purposive sample of 20 male and female retirees involved in a “Learning and Retirement” program. Innovations that both preserve a sense of self (internal Continuity) as well as those that allow one to strike out in entirely new direction are described, and, using a process of constant comparison, their motivational dynamics are explored. Given previous arguments that activity can be indiscriminate and disintegrative in some circumstance...
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reconsidering change and Continuity in later life toward an innovation Theory of successful aging
International Journal of Aging & Human Development, 2007Co-Authors: Galit Nimrod, Douglas A KleiberAbstract:This article examines the patterns and meanings of innovation in the activities of a group of retirees with an eye toward understanding the place and value of innovation in the aging process. Starting with a consideration of Continuity Theory, as a perspective that simply describes typical patterns of activity, and activity Theory that prescribes expansion of activities as a key to well-being, this article highlights the characteristics, meanings and perceived benefits of a wide variety of innovative activities. The study utilized in-depth semi-structured interviews with a purposive sample of 20 male and female retirees involved in a "Learning and Retirement" program. Innovations that both preserve a sense of self (internal Continuity) as well as those that allow one to strike out in entirely new direction are described, and, using a process of constant comparison, their motivational dynamics are explored. Given previous arguments that activity can be indiscriminate and disintegrative in some circumstances, we nevertheless suggest that innovation can be growth producing and liberating, even in later life, while at the same time generally protecting a sense of internal Continuity.
Sharon M Knight - One of the best experts on this subject based on the ideXlab platform.
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Continuity in sport participation as an adaptive strategy in the aging process a lifespan narrative
Journal of Aging and Physical Activity, 1999Co-Authors: David J Langley, Sharon M KnightAbstract:The broad purpose of this paper is to contextualize the meaning and evolution of competitive sport participation among the aged by describing the life story of a senior aged participant. We used narrative inquiry to examine the integration of sport into the life course and Continuity Theory to examine the evolution of his life story. Continuity Theory proposes that individuals are predisposed to preserve and maintain longstanding patterns of thought and behavior throughout their adult development. Based on this Theory, we suggest that Continuity in successful competitive sport involvement for this participant may represent a primary adaptive strategy for coping with the aging process. Successful involvement in sport appeared to mediate past and continuing patterns of social relationships, the development of personal identity, and a general propensity for lifelong physical activity.