Three aspects in determining the first natural frequency of steel joist supported floors were studied. The aspects are: 1) determining which finite element model best predict the behavior of joist-slab tee-beams, 2) investigating the ability of proposed equations to calculate the effective moment of inertia of joist-slab tee-beams, and 3) developing a finite element model to predict the first natural frequency of steel joist supported floors. Several finite element models were tested to determine which one best predicted the experimental results of six joist-slab setups. The model which best predicted the experimental results was used. Next, a study was done to determine the ability of a proposed equation to predict the effective moment of inertia of joist-slab tee-beams. The study modeled and analyzed 130 joist-slab configurations and compared the results to those calculated using the proposed equations. Finally, a finite element modeling technique was developed to predict the first natural frequency of steel joist supported floors. Seven in-situ floors were experimentally tested, and those results were compared to the predicted values given by the models. / Master of Science

Iron Oxide Nanoparticles (IONPs) are a multifunctional nano-material that allows for MRI imaging, intravenous-controlled drug movement, and hyperthermia. The objective of this study is to optimize and control IONP hyperthermia and cope with aggregation using Finite Element (FE) Modeling and statistical physics. The FE model is first used to demonstrate the advantages of changing IONP heat dissipation in time, which can increase energy density inside tumors while decreasing the energy delivered in healthy tissue. Here, this is defined as target-specificity. Second, this model is used to demonstrate that time-dependent IONP heat dissipation allows for control of temperature distributions inside the body. Third, the FE model is used to solve the temperature distributions resulting from capillary diffusion of IONPs. This study shows that capillary diffusion combined with direct injection results in improved homogeneity of temperature distributions. Fourth, using a square-difference scheme, non-time domain parameters including the number of IONP injections, the location of injections, IONP distribution width, and heating intensity are optimized to improve target-specificity and temperature homogeneity. Collectively, this study contributes to hyperthermia by optimizing time- and non-time- domain parameters, controlling hyperthermia, and quantifying aggregation with a new theory. / Master of Science

Master of Science / Department of Computing and Information Sciences / Torben Amtoft / An EFSM (Extended Finite State Machine) is a tuple (S, T, E, V) where S is a finite set of states, T is a finite set of transitions, E is a finite set of events, and V is a finite set of variables. Every transition t in T has a source state and a target state, both in S. There is a need to develop a GUI which aids in building such machines and simulating them so that a slicing algorithm can be implemented on such graphs. This was the main idea of Dr. Torben Amtoft, who has actually written the slicing algorithm and wanted this to be implemented in code. The project aims at implementing a GUI which is effective to simulate and build the graph with minimum user effort. Poor design often fails to attract users. So, the initial effort is to build a simple and effective GUI which serves the purpose of taking input from the user, building graphs and simulating it. The scope of this project is to build and implement an interface so that the users can do the following in an effective way:  Input a specification of an EFSM  Store and later retrieve EFSMs  Displaying an EFSM in a graphical form  Simulating the EFSM  Modify an EFSM  Implement the slicing algorithm All the above mentioned features must be integrated into the GUI and it should only fail if the input specification is wrong.

A common problem to all applications of linear finite dynamical systems is analyzing the dynamics without enumerating every possible state transition. Of particular interest is the long term dynamical behaviour, and if every element eventually converges on fixed points. In this paper, we study the number of iterations needed for a system to settle on a fixed set of elements. As our main result, we present two upper bounds on iterations needed, and each one may be readily applied to a fixed point system test. The bounds are based on submodule properties of iterated images and reduced systems modulo a prime.

In my dissertation, I developed mixed hp-finite element methods for linear elasticity with weakly imposed symmetry, which is based on Arnold-Falk-Winther's stable mixed finite elements. I have proved the h-stability of my method for meshes with arbitrary variable orders. In order to show the h-stability, I need an upper limit of the highest order of meshes, which can be an arbitrary nonnegative integer. / text

No description available.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 119-124).

In the present study, we propose a computational model for the linear and nonlinear analysis of shell structures. We consider a tensor-based finite element formulation which describes the mathematical shell model in a natural and simple way by using curvilinear coordinates. To avoid membrane and shear locking we develop a family of high-order elements with Lagrangian interpolations. The approach is first applied to linear deformations based on a novel and consistent third-order shear deformation shell theory for bending of composite shells. No simplification other than the assumption of linear elastic material is made in the computation of stress resultants and material stiffness coefficients. They are integrated numerically without any approximation in the shifter. Therefore, the formulation is valid for thin and thick shells. A conforming high-order element was derived with 0 C continuity across the element boundaries. Next, we extend the formulation for the geometrically nonlinear analysis of multilayered composites and functionally graded shells. Again, Lagrangian elements with high-order interpolation polynomials are employed. The flexibility of these elements mitigates any locking problems. A first-order shell theory with seven parameters is derived with exact nonlinear deformations and under the framework of the Lagrangian description. This approach takes into account thickness changes and, therefore, 3D constitutive equations are utilized. Finally, extensive numerical simulations and comparisons of the present results with those found in the literature for typical benchmark problems involving isotropic and laminated composites, as well as functionally graded shells, are found to be excellent and show the validity of the developed finite element model. Moreover, the simplicity of this approach makes it attractive for future applications in different topics of research, such as contact mechanics, damage propagation and viscoelastic behavior of shells.

Thesis (Ph.D.)--University of Delaware, 2009. / Principal faculty advisor: Gary L. Ebert, Dept. of Mathematical Sciences. Includes bibliographical references.

No description available.