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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"VARIATIONAL PRINCIPLES"”.
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Variational Principles in Finite Elasticity With Applications
A variational principle of the complementary energy type is derived. Trial functions for the actual deformation gradient are used in the formulation of the principle. Corresponding principles for elastic bodies subject to kinematical constraints such as incompressibility are formulated. The same …
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Supercritical Semi-Linear Elliptic Problems Using Variational Principles
The thesis investigates the use of variational methods to study elliptic partial differential equations (PDEs) with supercritical nonlinearities. By focusing on convex subsets of a Banach space, the research overcomes compactness issues typically encountered with nonlinearities that exceed the …
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On variational principles for dissipative networks and systems
… in general not derivable from a Lagrangian, but variational principles can nevertheless be formulated using auxiliary variables or a multiplying factor. Both methods are examined, generalized, and applied to some dissipative systems. Composite variational principles employ auxiliary variables in …
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New variational principles with applications to optimization theory and algorithms
… dissertation we investigate some applications of variational analysis in optimization theory and algorithms. In the first part we develop new extremal principles in variational analysis that deal with finite and infinite systems of convex and nonconvex sets. The results obtained, under the name of …
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ΣΥΜΒΟΛΗ ΣΤΗΝ ΑΝΑΛΥΣΗ ΚΑΙ ΣΤΟΝ ΥΠΟΛΟΓΙΣΜΟ ΑΚΟΥΣΤΙΚΟΕΛΑΣΤΙΚΩΝ ΦΑΙΝΟΜΕΝΩΝ
… POINT OF VIEW, DEVELOPING SUITABLE ORIGINAL VARIATIONAL PRINCIPLES. IN PART 3, THESE VARIATIONAL PRINCIPLES ARE DISCRETIZED USING THE FINITE ELEMENT METHOD, PRODUCING ALGEBRAIC SYSTEMS SUITABLE FOR PROCESSING WITH A COMPUTER. IN PART 4 THE DEVELOPMENT OF THE ACE ANALYSIS SYSTEM IS ANALYSED, …
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Shape Optimization of Microfiber Composite Energy Harvesters
… of motion were derived using Hamilton’s variational principles and constitutive relations of a piezoelectric material. The mathematical model developed in Matlab was validated with an experiment and frequency response functions. The validated model was used to perform shape optimization …
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Large deformation behavior of long shallow cylindrical composite panels
… strain-displacement relations, and applying variational principles. The response is investigated for the case of a panel loaded exactly at midspan and for a panel with the load offset from midspan. The mathematical formulation is one-dimensional in the circumferential coordinate. Solutions …
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Estudo da validade da hipótese de Kirchhoff-Love na Teoria das Placas
… linear theory of elasticity and standard energy variational principles. Analytical expressions of deflections and resultant stresses are treated for rectangular plates subjected to transverse uniformly distributed loadings considering the following boundary conditions: Case 1 - Four simply …
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Polygonal finite elements for finite elasticity
… theoretical framework of deriving the two-field variational principle, involving a displacement field and a pressure field, is presented. Within the theoretical framework, by assuming different forms of stored-energy function, two types of variational principles are obtained, each with distinct …
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Structure-preserving Numerical Methods for Engineering Applications
… is focused on numerical schemes derived from variational principles – schemes that are general enough to apply to a large class of engineering problems. A theoretical framework that encapsulates variational integration for mechanical systems with external forcing and time-dependence and which …
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Dynamic Analysis of Interfacial Cracks in Composite Laminates
… employing Lekhnitskii's stress functions and the variational principles of a hybrid functional. An iterative scheme for determining the closure size of a partially closed crack is proposed. Solutions for the orders of stress singularity of interfacial cracks in graphite-epoxy composites with …
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Vibration Attenuation of Composite Moving Beams using Active Vibration Control Techniques
… The governing equations are obtained using variational principles. The displacement constraints are applied through Lagrange multipliers. An over hanging beam is considered for the analysis purpose. First bending mode shape is taken as the initial shape of the beam. Newmark's time …
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Asmptotically Plane Wave Spacetimes
… review the necessary background on plane waves, variational principles for gravity and black holes in higher dimensions. We then propose a definition of asymptotically plane wave spacetimes in vacuum gravity in terms of the asymptotic fall-off of the metric and discuss the relation to previously …
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The edge of thermodynamics : driven steady states in physics and biology
… motion characteristic of living things. Formal variational principles have recently been discovered for nonequilibrium systems that characterize their steady-state properties in terms of generalized thermodynamic quantities. Concrete computations using these principles can usually only be …
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Stochastic Geometric Mechanics and Symmetry
… systems, in Hamiltonian as well as Lagrangian (variational) formulations. On the Hamiltonian side, we discuss a stochastic Kepler problem with a noisy angular momentum vector. We show that the radial distance and speed evolve deterministically. This allows us to regularize collisional …
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New PDE models for imaging problems and applications
Variational methods and Partial Differential Equations (PDEs) have been extensively employed for the mathematical formulation of a myriad of problems describing physical phenomena such as heat propagation, thermodynamic transformations and many more. In imaging, PDEs following variational …
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Power efficiency analysis for an Active structure
… of methods based on numerical integration, variational principles, and finite element analysis. The fundamental result of this work is that computing the power efficiency of an active structure reduces to the solution of two eigenvalue problems. The maximum possible sound power radiated by a …
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Numerical simulation and modeling of two-phase flows using the volume-of-fluid method
… on wings. The VOF approach is derived from variational principles. Additionally, it uses the idea that the role of curvature in a speed function 𝑉 is analogous to the role of viscosity in the corresponding hyperbolic conservation law to propagate complex topologies where singularities may …