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 43 for “"incompressibility"”.
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Kinematic Constraints in Nonlinear Elasticity (Incompressibility, Perturbation, Convergence)
The constitutive equations for a material which approximately satisfies a kinematic constraint are investigated for the particular case of an elastic material.
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Variational Principles in Finite Elasticity With Applications
… subject to kinematical constraints such as incompressibility are formulated. The same approach can be used to obtain variational principles for infinitesimal deformations superposed on a known finite elastic deformation of an elastic body.
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Splitting solution scheme for material point method
… several limitations exist. In the limit of incompressibility, a significantly small time step is required to ensure the stability of the explicit formulation. Time step size restriction is also present in low permeability cases in porous media analysis. Spurious pressure oscillations are …
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Finite element analysis of eigenvalue problems in the stability of fluid motions
… The penalty method is used to approximate the incompressibility condition. We consider the stability of Boussinesq flows in a two-dimensional box in which internal heat sources are present. The influence of side walls are studied for various boundary conditions and width-to-height ratios. The …
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Prostate Tissue Motion Tracking and Ultrasound Elastography Using Tissue Mechanics Derived Constraints
… is then refined through an algorithm where incompressibility, Laplacian smoothing, and strain compatibility are enforced. The refined displacement field can generate a strain image of the prostate. Material properties such as Young’s modulus, Poisson’s ratio, and shear modulus can be …
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A Continuous/Discontinuous FE Method for the 3D Incompressible Flow Equations
… in the momentum equations is employed. The incompressibility constraint is enforced by numerically solving the Poisson equation for pressure using a continuous Galerkin (cG) discretization. The main advantage of the method is that is does not require the velocity and pressure approximation …
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A virtual element method for transversely isotropic elasticity
… This work focuses on the treatment of near-incompressibility and near-inextensibility. These are explored both for homogeneous problems, in which the plane of isotropy is fixed; and non-homogeneous problems, in which the fibre directions defining the plane of isotropy vary with position. In …
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A penalty finite element model for axisymmetric flows of power-law and white-metzner fluids
… of the penalty method to introduce the incompressibility constraint. However, the pressure can be post-computed once the velocities are obtained. The finite element models are used to analyze several plane and axisymmetric flows of power-law and White-Metzner fluids. The effect of …
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On the predictive capability and stability of rubber material models
Due to the high non-linearity and incompressibility constraint of rubber materials, the predictive capability and stability of rubber material models require specific attention for practical engineering analysis. In this thesis, the predictive capability of various rubber material models, namely …
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A Semi-analytical Model for Nonlinear Elliptical Inclusions with Spherical Eigenstrains
… 2D elliptical inclusion problem, which satisfies incompressibility. It is shown to converge to the Eshelby solution in the linear limit for the case of isotropically growing inclusions. Moreover, this model matches almost identically to 2D finite element simulations for large incompatibilities, …
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Equivalent plastic strain for the Hill's yield criterion under general three-dimensional loading
… vector are not independent under plastic incompressibility. To remedy this, a reduced-order system was defined in terms of deviatoric stress, with one normal component eliminated, so that the previous method could be applied; the eliminated component was reintroduced in the final …
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Elastography using optical coherence tomography : development and validation of a novel technique
… algorithm by incorporating strain smoothness and incompressibility constraints into the estimation algorithm.
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Microscopic dynamical studies of the effects of the nuclear equation of state in intermediate-energy heavy-ion collisions
… that the theory is very useful for deducing the incompressibility of matter from collision data.
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Analysis and finite element approximation of an optimal shape control problem for the steady-state Navier-Stokes equations
… applied to relax the difficulty of dealing with incompressibility in conjunction with domain perturbations and regularity requirements for the solutions. The existence of optimal solutions for the penalized problem is presented. The computation of the shape gradient and its treatment plays …
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MITIGATION OF GEAR MESH-FREQUENCY VIBRATIONS UTILIZING A HYDROSTATIC BEARING
… support. Previous research has assumed the incompressibility of the working fluid in a hydrostatic bearing. In practice, the working fluid is not incompressible and the effect is not necessarily insignificant. Using the compressibility of the working fluid and the unique properties of a …
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Existence and stability of solutions to the equations of fibre suspension flows
… equations are balance of linear momentum, the incompressibility condition, an evolution equation for A, and a constitutive equation for the stress. The evolution equation contains a fourth-order orientation tensor A, and it is necessary to approximate A as a function of A, through a closure …
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Exponential Integrators for the Incompressible Navier-Stokes Equations
… NSE constitute a system of DAEs, where the incompressibility condition is the algebraic constraint. Exponential integrators can be extended to DAEs with linear constraints imposed via a projection onto the constraint manifold. This results in a projected ODE that is integrated by a KBEI. In …
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A Class of Stable, Efficient Navier-Stokes Solvers
… with given boundary value of velocity. The incompressibility constraint and non-slip boundary condition have made this problem very challenging. Their treatment by finite element method leads to the well-known inf-sup compatibility condition. Their treatment by finite difference method leads …
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A virtual element method for hyperelasticity
… behaviour in the limiting cases of near-incompressibility and near-inextensibility, both separately and combined.
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