Global ETD Search
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 39 for “"Internal Variables"”.
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Modeling of materials with internal variables using a thermomechanical approach
… this thesis, the thermomechanical approach with internal variables has been thoroughly analyzed. This approach is based on the combination of thermodynamic principles and continuum mechanics. Therefore it reflects the physical essence of constitutive behavior of materials. Based on this approach, …
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Plasticity and non-simple materials
… are derived within the context of a theory with internal variables using the ""Coleman-Noll"" procedure. Models of conventional and gradient-dependent, rate-independent thermo-plasticity are developed based on the foregoing thermodynamic relations. In contrast with generalized elasticity, it is …
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The Chaco connection: Bonito style architecture in outlier communities
… emulate or compete with neighboring communities. Internal architectural elements presumably could not be replicated by outsiders who lacked access to the information, so "internal" variables such as banded veneers and kiva/room ratio were compared across the outlier data base. If outlier Bonito …
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Internal Variable and Temperature Modeling Behavior of Viscoelastic Structures -- A Control Analysis
… structures with damping modeled by means of internal variables. Thermodynamic principles are used to develop models, which are based on a generalized Maxwell element. Initially, studies are conducted to verify how the method of reduced variables can be applied to account for temperature …
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Variational formulations and numerical analysis of some problems in small strain elastoplasticity
… be formulated as variational inequalities, with internal variables being included explicitly in the formulation. Corresponding minimisation problems follow naturally from standard results in convex analysis.
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ΓΡΗΓΟΡΟΙ ΑΛΓΟΡΙΘΜΟΙ ΓΙΑ ΤΗΝ ΤΑΥΤΟΠΟΙΗΣΗ ΣΥΣΤΗΜΑΤΩΝ ΜΕ ΓΡΑΜΜΙΚΗ ΦΑΣΗ
… LEVINSON-TYPE AND SCHUR TYPE. THE INVOLVED INTERNAL VARIABLES ARE ALL SYMMETRIC BECAUSE THE ALGORITHMS ARE DEVELOPED SO AS TO RESPECT THE SYMMETRY WHICH IS INTRINSIC IN THE LINEAR PHASE PROBLEM. THE COMPUTATIONAL COMPLEXITY OF THE PROPOSED ALGORITHMS IS CONSIDERABLY LOWER COMPARED TO …
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Adaptive finite elements for viscoelastic deformation problems
… introduction of a set of unobservable interval variables. In the linear viscoelastic case we exploit the structure of the quasistatic problem to remove the displacement from the equations governing the internal variables. This results in an elliptic problem with right hand side dependent on the …
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Some structural theorems for inelastic solids : an internal variable approach.
… involving thermodynamic potential functions with internal variables is reviewed. Use is made of the condition for stable thermodynamic equilibrium in order to obtain dual minimum principles for the equilibrium state of a solid inelastic body. This leads to dual forms of the incremental (or rate) …
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Viscoelasticity of Articular Cartilage and Ligament: Constitutive Modeling and Experiments
… this study based on the short-term and long-term internal variables. The constitutive model was particularized for both tissues, numerically implemented into the finite element software package ABAQUS and the material parameters were identified using the available experimental data. The …
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Modelagem constitutiva de ligas magnéticas com memória de forma
… with a novel constitutive model based on internal variables that describe the phenomenological behavior of MSMAs. The model formulation is developed within the framework of continuum mechanics and thermodynamics, defining a mixture for the free energy potential based on four macroscopic …
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Mathematical modelling, finite dimensional approximations and sensitivity analysis for phase transitions in shape memory alloys
… distributed and boundary inputs and internal variables. Well-posedness is obtained using an abstract formulation in an appropriate Hilbert space and explicit decay rates for the associated linear semigroup are derived. Numerical experiments using finite-dimensional approximations are …
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Spline based controller for nonlinear systems
… whose parameters are obtained, require the internal variables of the machines. These variables are verified by using a proposed internal variable identifying algorithm. The objective is to design nonlinear excitation controllers for power system stability enhancement. Spline techniques are …
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Modeling of Hysteretic Behavior of Beam -Column Connections Based on Self -Learning Simulation
… In the proposed model, two energy-based internal variables are introduced to expedite the learning of hysteretic behavior of materials or structural components. The model has significant advantages over conventional models in that it can handle complex behavior due to local buckling and …
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Ductile fracture modeling : theory, experimental investigation and numerical verification
… dependence and the non-linear damage rule. Two internal variables are adopted to quantify the evolution of material properties. One is the plastic strain and the other is so-called damage variable. The joint effects of pressure and Lode angle define a fracture envelope in the principal stress …
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Non-Equilibrium Thermodynamics of porous media filled by a fluid flow and of rigid bodies with an internal tensorial field influencing the thermal phenomena.
… porous media and of rigid bodies with an internal tensorial field influencing the thermal phenomena, respectively. Furthermore, three Appendices are present, that clarify some aspects of the arguments presented in the second, third, fourth, and seventh Chapters. Regarding the first Part, …
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Damage Development in Static and Dynamic Deformations of Fiber-Reinforced Composite Plates
… damage modes are modeled using the theory of internal variables and the delamination by postulating a failure envelope in terms of the transverse stresses; the damage degrades elastic moduli. The delamination of adjoining layers is simulated by the nodal release technique. Coupled nonlinear …
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On the two-potential constitutive modelling of rubber viscoelastic materials
U of I Only Restriction Lifted for Item 93166 on 2018-07-08T09:15:36Z.
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Robust Distributed Stabilization of Interconnected Multiagent Systems
… of these infrastructures, only a few internal variables of each agent might be measurable and the exact knowledge of the model might be unavailable for the control design purpose. The collective objectives may range from consensus to decoupling, stabilization, reference tracking, and …
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Modelagem de fratura dúctil em colisão de embarcações utilizando modelo de dano de Lemaitre modificado
… the Continuum Damage Mechanics (CDM), where new internal variables are inserted in the material constitutive equations, related to the damage produced by the stress field. The objective of this thesis is to propose and assess a modification in Lemaitre’s damage model, called Model with …
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Constitutive equations and failure criteria for amorphous polymeric solids
… In addition to the standard kinematic and stress variables, their theory contains two internal variables: a variable s > 0 that represents an isotropic intermolecular resistance to plastic flow; and an unsigned variable 7 that represents the local free-volume. In this thesis, we extend the work of …
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