Thesis (doctoral)--University of Tartu, 2006. / Vita. Includes bibliographical references.

A finite strip analysis of sandwich wood panels is presented. The panels consist of upper and lower plates stiffened by beams (joists) in one direction only. The analysis considers a Fourier series expansion in the stiffeners' direction and a polynomial finite element approximation in the direction normal to the stiffeners. The number of degrees of freedom is 34, which includes also the lateral and torsional deformation of the joists. This permits consideration of the effect of joist bridging on the maximum deflection and bending stresses. A maximum of 20 joists per panel can be analysed. The modulus of elasticity(E) of the joists may be selected randomly from a distribution, and controlled to be within a given range. The upper and lower plates may possess orthotropic properties. Nails connect the plates to the joists. Nailing may be considered either as a continuous or as discrete connectors. The loading may be in the form of an uniformly distributed load spread over the entire panel or over a maximum of 20 smaller (concentrated) areas of the top plate. Numerical investigations have been carried out to verify the program. Parametric studies have been done to understand the behavior of the model. Lastly, the formula for shear lag given by CSA Standard CAN3-086.1-M84 is checked against the shear lag obtained from the current computer program. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

A solution procedure based on the finite strip method is presented herein, for the analysis of plate systems exhibiting geometric and material non-linearities. Special emphasis is given to the particular problem of rectangular plates with stiffeners running in a direction parallel to one side of the plate. The finite strip method is selected for the analysis as the geometry of the problem is well suited for the application of this method and also as the problem is too complicated to solve analytically. Large deflection effects are included in the present study, by taking first, order non-linearities in strain-displacement relations into account. Material non-linearities are handled by following von-Mises yield criterion and associated flow rule. A bi-linear stress-strain relationship is assumed for the plate material, if tested under uniaxial conditions. Numerical integration of virtual work equations is performed by employing Gauss quadrature. The number of integration points required in a given direction is determined either by observing the individual terms to be integrated or by previous experience. The final set of non-linear equations is solved via a Newton-Raphson iterative scheme, starting with the linear solution. Numerical investigations are carried out by applying the finite strip computer programme to analyse uniformly loaded rectangular and I beams with both simply supported and clamped ends. Displacements, stresses and moments along the beam are compared with analytical solutions in linear analyses and with finite element solutions in non-linear analyses. Investigations are also extended to determine the response of laterally loaded square plates with simply supported and clamped boundaries. Finally, a uniformly loaded stiffened panel is analysed and the results are compared with finite element results. It was revealed that a single mode in the strip direction was sufficient to yield engineering accuracy for design purposes, with most problems. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Settling basins can be shortened by using a stack of horizontal parallel plates which develop boundary layers in which sedimentation can occur. The purpose of this study is to examine the design parameters for such a system and to apply this approach to a fish rearing channel in which settling length is strictly limited. Flow between parallel rough and smooth plates has been modelled together with sediment concentration profile. Accurate description of boundary layer flow requires the solution of Navier-Stokes equations, and due to the complexity of the equations to be solved for turbulent flow some assumptions are made to relate the Reynolds stresses to turbulent kinetic energy and turbulent energy dissipation rate. The simplified equations are solved using a numerical method which uses the approach given by the TEACH code. The flow parameters obtained from the turbulent flow model are used to obtain the sediment concentration profile within the settling plates. Numerical solution of the sedimentation process is obtained by adopting the general transport equation. The lower plate is assumed to retain sediments reaching the bottom. The design of a sedimentation tank for a fish rearing unit with high velocity of flow has been investigated. The effectiveness of the sedimentation tank depends on the uniformity of flow attained at the inlet, and experiments were conducted to obtain the most suitable geometric system to achieve uniform flow distribution without affecting other performances of the fish rearing unit. The main difficulties to overcome were the heavy circulation present in the sedimentation tank and the clogging of the distributing system by suspended particles. Several distributing systems were investigated, the best is discussed in detail. It was concluded that a stack of horizontal parallel plates can be used in fish rearing systems where space is limited for settling sediments. Flow distribution along the vertical at the entrance to the plates determines the efficiency of the sediment settling process and a suitable geometrical configuration can be constructed to distribute the high velocity flow uniformly across the vertical. Numerical modelling of sediment removal ratio for flow between smooth and rough parallel plates has been calculated. The results show that almost the same pattern of sediment deposition occurs for both the smooth-smooth and rough-smooth plate arrangements. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (M.S.E.)--University of Alabama in Huntsville, 1968. / Typescript (photocopy).

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 304-311). Also available via the Internet.

Thesis (Ph. D. in Applied Mathematics)--Naval Postgraduate School, June 2003. / Dissertation supervisor: Don Danielson. Includes bibliographical references (p. 99-100). Also available online.

Thesis--M. Sc.(Eng.), University of Hong Kong, 1983.

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