No description available.

No description available.

No description available.

An analytical procedure, which retains the influence of finite deflections, is developed herein for the dynamic behaviour of rectangular shaped rigid-plastic beams. In the general formulation of the problem deformation is assumed to proceed under two distinct mechanisms depending on the extent to which the value of the peak pressure exceeds the static collapse pressure of the beam. These mechanisms are described by kinernatically admissible velocity fields that satisfy the appropriate continuity conditions. The governing equations of motion are derived from a variational statement consisting of the principle of virtual work and D'Alembert's principle. The conventional parabolic yield surface (which describes the coupling action between axial forces and bending moments at yield) and its associated flow rule are adopted to describe the plastic behaviour of the beam material. The kinematic small but finite deflection analysis, in which the membrane forces and bending moments interact, generally leads to basic equations which are of nonlinear character. These resulting equations are solved analytically and closed form expressions are developed for the prediction of maximum permanent deformation of the beam. A dynamic membrane analysis is carried out in those cases when the input energy is sufficiently high that the beam undergoes moderately large deformation (i.e. deflections of the order of beam thickness). Finally the dependence of the permanent deflection on the applied pressure and impulse is obtained for a family of rectangular pulses. This relationship is represented by an isoresponse curve in a form convenient for direct engineering use. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Call number: LD2668 .T4 1979 T62 / Master of Science

Thesis (M.Eng.)--Memorial University of Newfoundland, 2005. / Restricted until May 2006. Bibliography: leaves 114-122.

No description available.

This is an experimental study of the plastic yielding of steel columns. It consists of tests of four specimens; two tension coupons, a 12-inch stub column and a 21-inch stub column. The tension tests were used to determine the physical properties of the material while the stub columns demonstrated the effects of residual stress upon the initiation of yielding and the propagation of the yielding. The test procedure used in both the tension tests and the compression tests was the same. The specimen was loaded in increments up to a load just, below the yield point. Beyond that point the specimen was strained at a constant rate in order to neutralize the effects of creep. This test procedure required that all the data for each set of readings be adjusted to give the strain at any gauge on the specimen at the same instant of time. This was done by considering the differences between consecutive sets of readings and adjusting all strains to the strain at the gauge showing the greatest change during the set. This was done by means of a computor [sic] program. During the tests of the stub columns local buckling of the flanges and web was restrained by a system of bars and bracing frames. The system used in the test of the 21-inch stub column proved to be particularly successful. Data was collected from strain gauges in the tension tests and strain and dial gauges in the compression test. The dial gauges in the compression test provided confirmation that the strain gauges accurately represented the state of strain in the specimens and also rotation of the upper end of the stub columns during the tests. There are several general conclusions which, it must be emphasized, are based upon a small number of tests. The yield stress of the tension specimens was greater than of the compression specimens. Yielding initiates at several independent foci rather than propagating from one single point. Yielding, once commenced, generally continued without stopping well into the strain hardened region. Therefore, there are both unyielded material and strain hardened material in the specimen at the same time. The initiation and progress of plastic deformations in the specimen are greatly affected by even small local irregularities. The effect of residual stresses upon the initiation of yielding is not uniform. The strain hardening modulus of the specimens used has been found to be only about one-half of that expected. Wide variation of this property is common. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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

"November 1967." / Includes bibliographical references / 2 v. : ill., plates ; 1967 / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil Engineering, 1968