No description available.

No description available.

Thesis (M.App.Sc.) - Carleton University, 2002. / Includes bibliographical references (p. 90-94). Also available in electronic format on the Internet.

The purpose of this paper is to develop a general method for using Finite Elements in the Steepest Descent Method. The main application is to a partial differential equation for a Transonic Flow Problem. It is also applied to Burger's equation, Laplace's equation and the minimal surface equation. The entire method is tested by computer runs which give satisfactory results. The validity of certain of the procedures used are proved theoretically. The way that the writer handles finite elements is quite different from traditional finite element methods. The variational principle is not needed. The theory is based upon the calculation of a matrix representation of operators in the gradient of a certain functional. Systematic use is made of local interpolation functions.

No description available.

No description available.

This research investigation explores the feasibility of implementing a laser welded sandwich steel panel bridge deck system as a viable alternative to standardized reinforced concrete bridge decks. Generally used in naval ship building applications, steel sandwich panels possess attractive characteristics towards the integration with bridge infrastructure such as service life in excess of 100 plus years, dead load reduction, rapid construction, decreased closure time, and automated mass production. The lack of fatigue data for the laser "stake" welds used to create the enclosed sandwich panel geometry raised concerns with respect to fatigue life. The primary focus of this study was to determine whether or not infinite fatigue life was possible. Two different laser welding technologies were investigated, Laser Beam Welding (LBW) and Hybrid-Laser Arc Welding (HLAW). Test specimens were fabricated and tested in order to examine fatigue resistance based on a localized load effect between adjacent core stiffeners. Finite element models were used to obtain the stress range for each individual test due to complex geometry and partially restrained boundary conditions. In order to assess the fatigue performance of the overall deck system, additional finite element models were created to study the local and global behavior of different sandwich panel configurations. As a whole the investigation yielded promising results. Infinite fatigue life is achievable due to outstanding fatigue performance. The HLAW stake welds demonstrated superior fatigue resistance in comparison to the LBW process. Localized load effects can be minimized through the modification of different panel parameters. Pushing forward, full scale testing is essential to the future employment of this innovative bridge deck system. / Master of Science

This thesis develops an immersed finite element (IFE) space for numerical simulations arising from beam design with multiple materials. This IFE space is based upon meshes that can be independent of interface of the materials used to form a beam. Both the forward and inverse problems associated with the beam equation are considered. The order of accuracy of this IFE space is numerically investigated from the point of view of both the interpolation and finite element solution of the interface boundary value problems. Both single and multiple interfaces are considered in our numerical simulation. The results demonstrate that this IFE space has the optimal order of approximation capability. / Master of Science

Thesis: B.S., Massachusetts Institute of Technology, Department of Mechanical Engineering, 1978 / Includes bibliographical references. / by Arthur P. Cimento. / B.S. / B.S. Massachusetts Institute of Technology, Department of Mechanical Engineering

A direct solution procedure is proposed and developed which exploits the parallelism that exists in current symmetric multiprocessing (SMP) multi-core processors. Several algorithms are proposed and developed to improve the performance of the direct solution of FE problems. A high-performance sparse direct solver is developed which allows experimentation with the newly developed and existing algorithms. The performance of the algorithms is investigated using a large set of FE problems. Furthermore, operation count estimations are developed to further assess various algorithms. An out-of-core version of the solver is developed to reduce the memory requirements for the solution. I/O is performed asynchronously without blocking the thread that makes the I/O request. Asynchronous I/O allows overlapping factorization and triangular solution computations with I/O. The performance of the developed solver is demonstrated on a large number of test problems. A problem with nearly 10 million degree of freedoms is solved on a low price desktop computer using the out-of-core version of the direct solver. Furthermore, the developed solver usually outperforms a commonly used shared memory solver.