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Showing 1 to 17 of 17 for “"Deformation gradient"”.
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Variational Principles in Finite Elasticity With Applications
… 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 approach can be used to obtain variational …
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Three-field mixed finite element approximations for problems in elasticity
… displacement, first Piola-Kirchhoff stress, and deformation gradient. Of particular interest is the design and analysis of mixed formulations that are uniformly stable in the incompressible limit. The first part of the thesis deals with problems in linear elasticity. Lamichhane, Reddy and …
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Plasticity and non-simple materials
… plasticity and various classes of second-deformation-gradient plasticity 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 …
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Continuity in Rigid Viscoplastic Flow
… plasticity. This approach emanates from how the deformation has been described, e.g. the multiplicative decomposition of the deformation gradient. In the present work, a continuity condition is derived for the elastic spin field from a conservation law for Burgers vector content---a consequence …
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Some more problems of geodynamics
… are crucial in computing Earth’s long-period deformation. Our approach is based on the transformation of Poisson’s equation into an equivalent equation posed on a spherical computational domain. This new problem is solved in an efficient iterative manner based on a hybrid …
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Nonlinear Electromechanical Deformation of Isotropic and Anisotropic Electro-Elastic Materials
… class of active materials, which produce large deformations in response to an electric stimulus. EAPs have attractive characteristics of being lightweight, inexpensive, stretchable, and flexible. Additionally, EAPs are conformable, and their properties can be tailored to satisfy a broad range of …
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Deformation behavior of cylindrical block copolymer bicrystals : pathway to understanding block copolymer grain boundaries
… of pure tilt grain boundaries. The study of the deformation of the bicrystals, each containing one grain boundary, enables a deeper understanding of the influences grain boundaries and the incompatibilities between them have on mechanical behavior. Mechanical properties and deformation of …
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Numerical simulation of friction welding processes: An arbitrary Lagrangian-Eulerian approach
… model is used, which is suited for the large deformations characteristic of friction welding processes, and which resolves the viscoplastic deformations in the thermomechanically affected zone as well as the elastic stresses in the parent material. To prevent the large deformations from …
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Folding of stratigraphic layers in ice domes
… of an ice core. This study focuses on this deformation, treating the disturbed strati-graphic layers as passive markers in the large-scale flow.The two major tools that I use to study overturning are core-relative isochrones (precores) and the deformation gradient tensor along a particle …
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A Mathematical Discussion of Corotational Finite Element Modeling
… similar corotational methods analyse non-linear deformation of a body by its discretization into finite elements, each with an orthogonal frame rotating (and translating) with the element. Such methods are well suited to deformations where non-linearity arises from rigid body deformation but …
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On the Continuum-Mechanics of Nematic Elastomers
… with the basic kinematic ingredients being the deformation of material particles and the orientation of the nematic microstructure. The kinetics of our theory consist of separate momentum balances for forces acting conjugate to each kinematic variable. We restrict our attention to a purely …
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A Geometrically nonlinear curved beam theory and its finite element formulation
… stresses, are obtained through the deformation gradient tensor of the current beam configuration relative to the initially curved beam configuration. The Green strains and Eulerian strains are explicitly represented in terms of the engineering strain measures while other stresses, …
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Continuum Mechanics Modelling of Corrugated Board
… Firstly, the focus is the problem of finite deformation hygro-elasticity. The assumption of kinematics is based on an additive split of the stretch in an elastic part and a non-elastic part. In time stepping sequences the elastic stretch is updated by the use of the total stretch from the …
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Kinematics of The Human Shoulder Complex: Model Registration, X Ray Videoradiography and Soft Tissue Artefacts
… a challenging task. This is primarily due to the deformation of the soft tissue causing relative motion between the markers and underlying skeletal structure. This effect is known as soft tissue artefacts (STAs) and it leads to violation of rigid body assumptions, which can result in significant …
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Optomechanics of two- and three-dimensional soft photonic crystals
… structures that undergo highly nonlinear deformation due to strain or other external stimulus such as temperature, pH etc. This can in turn dramatically affect optical properties such as light transmittance. Moreover certain classes of lithographically fabricated structures undergo some …
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Constitutive modeling of glassy memory polymers
… their original shape even after undergoing large deformations. The temporary shape is stable and return to the original shape is triggered by a suitable mechanism such heating the polymer above a transition temperature. Glassy shape memory polymers are called glassy because the temporary shape is …
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Mechanical response of polyether polyurethane foams under multiaxial stress and the initial yielding of ultrathin films
… of displacements affine with the applied mean deformation gradient, and left to rotate freely. The unit cell is characterized using a few physically meaningful material and geometric parameters whose values may be readily estimated for any given foam. We verify that under uniaxial loading the …