Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1959. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 110).

A visco-elastic-plastic mathematical model developed at Sheffield City Polytechnic was used to calculate the thermal stress and strain generated during the quenching of an infinite plate of high hardenability steel (835M30) in water, nine experimental oils and a polymer. In.the case of water, previous comparisons between experimental and calculated residual strains was poor. This discrepancy, during the present investigation, was reduced by introducing into the model the relationship between actual surface temperature and surface heat transfer coefficients and by incorporating the effects of various surface finishes into the model. However this discrepancy still remains to a limited extent. The same mathematical model was used to investigate the quenching characteristics of a number of experimental oils: overall the calculatedresidual stresses and strains compared well with the corresponding experimental data. The experimental oilscontained mixtures of additives. Those based on sodiumsulphonate increased the rate of cooling during quenching and the associated absolute residual stresses at a fixed point in the plate. Simultaneously the residual strains were reduced. The use of the succinimide additive produced converse effects in each case. The investigation also included the quenching of plates in polymer solutions of varying concentrations to provide a basis for comparison between the three most commonly used quenchants, viz. water, oil and water soluble polymers. The results indicated that in terms of the residual stresses and strains the oils produced smaller values particularly in the latter case when compared with the polymers. However when compared with water both the oils and water soluble polymers produced significantly smaller residual stresses and strains. The quenching characteristics were also investigated by the use of photography which gave an insight into the cooling characteristics of each quenchant. A water quench produced masses of fine bubbles during the nucleate boiling stage whilst this stage was characterised by large vapour blisters moving up the face of the plate in the case of the experimental oils. Previous photographic evidence indicated that solid polymer was deposited during quench and coated the plate with a gel-like substance which returned back into solution when the temperature was low enough.

A bar cell in the form of an isosceles trapezoid suitable for solution of two dimensional problems is introduced involving two new concepts, one that of overlapping bars and the other of a variable angle parameter. Based on the Identity of corner displacements of the cell and a similarly shaped piece of plate in conditions of uniform stress, expressions for the bar areas are derived in terms of Poisson's ratio, the geometry of the cell and a variable angle parameter. The stiffness matrix of the cell is derived further by combining different displacement modes. Two methods of calculating stresses, one by the nodal displacements and the other by the nodal force concentrations, are described. Two examples involving a rectangular plate and a partial sector of a circular plate illustrate the application of the finite element method using trapezoidal bar as well as no-bar cells and their results are compared with the exact elasticity solution. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Single plate connections for steel beams, connected by high strength bolts to the beam web and welded to the column, were investigated to determine their, behaviour. Tests were performed on the connections in the absence and in the presence of shear, and shear was found not to affect the rigidity of the connections. Varying the gauge distance, the weld size, the pitch and the number of bolts in the test specimens, showed that only the pitch and the number of bolts influenced the rigidity of the connections. An increase in the pitch and the number of bolts causes an increase in the rigidity of the connections. In all cases the major slip value was greater than the usually assumed value. Under the action of pure moment the centre of rotation was found to be slightly above the centroid of the connection, whereas under the action of moment and shear the centre of rotation was slightly below the centroid of the connection. The maximum moment developed by the connections varied from 45 kip-inches for the two-bolt connection, to 355 kip-inches for the six-bolt connection. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Experimental investigations of the surface roughness effect on heat transfer have been extensively conducted since the initial work by Cope; however, they were mostly limited to internal flow geometries--circular tubes, annuli or rectangular ducts.

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