The plastic hinge position in a bent cantilever struck normal to its plane by a steady jet applied at its tip

The position of the plastic hinge in a cantilever, which is bent in its own plane at an angle less than or equal to 90°, (see Fig. 1), when struck normal to its plane by a steady jet force at its tip, is determined after assuming the pipe material to be rigid-perfectly plastic. Some numerical results are presented to assist in the discussion of pipe-whip problems.     

Triple plastic hinge mechanism for a bent cantilever beam subjected to an out-of-plane tip force pulse of finite duration

In Ref. [1], the need was demonstrated for a deformation mechanism consisting of three plastic hinges (triple-hinge mechanism) to complete the range of possible deformation modes for a bent, rigid perfectly-plastic cantilever beam subjected to a suddenly applied constant tip force applied perpendicular to the plane of the cantilever. This paper provides the analysis of the transient behaviour of such a mechanism when a rectangular force pulse (constant force applied for a finite duration) is applied to the beam. The kinematics of the various hinges are described and the partitioning, of the input energy between the five phases of the motion is evaluated.     

Interaction of a jet with a plane boundary located normal to the jet axis

The interaction of plane and axiosymmetric subsonic jets with a plane boundary located normal to the jet axis is studied. A numerical solution for the equations of motion and energy is obtained, assuming stationary flow and constancy of liquid properties.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 22, No. 1, pp. 50–58, January, 1972.     

Investigation of heat transfer in a region of gradient flow when a plane turbulent jet is incident on a flat plate normal to the flow

The boundary conditions are determined experimentally for a system of differential equations describing heat transfer in a region of gradient flow when a plane turbulent jet is incident on a flat plate normal to the flow. The analytical solution is compared with direct measurements.Translated from Inzhenerno-Fizicheskii Zhurnal, Vo. 18, No. 4, pp. 631–637, April, 1972.     

Modeling of plastic yielding at a crack tip by inclined slip planes

This paper is concerned with the problem of inclined slip planes as a model of the plastic yielding region at a crack tip under conditions of plane strain. Some of the disagreements in the literature are discussed and comparisons are made with the results in the present study. To characterize the location of the plastic zones, an ad hoc criterion is used to choose an angle of inclination for the slip bands.

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Résumé Ce mémoire est relatif au problème des plans de glissement inclinés utilisés comme modèle pour une région sujette à des glissements plastiques à l'extrémité d'une fissure soumise à un état plan de déformation. Certains des désagréments signalés dans la littérature sont discutés, et des comparaisons sont établies avec les résultats de la présente étude.Pour caractériser la localisation des zones de déformation plastique, on recourt à un critère ad hoc pour choisir l'angle d'inclinaison des bandes de glissement.

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This work was conducted while the author was a graduate student in the Division of Applied Sciences, Harvard University, Cambridge, Massachusetts 02138.     

The strain energy released when a crack grows normally from its tip

The strain energy release rate for a crack growing from the tip of, and perpendicular to, an initial straight crack is calculated using finite element analysis under mixed-mode conditions. The results can be represented by a simple equation involving K _I and K _II.     

Initiation of adiabatic shear failure in a clamped circular plate struck by a blunt projectile

This paper presents an analytical model for studying the material failure in shear hinges formed during the dynamic plastic response of a circular plate under projectile impact. Analytic solutions for the ballistic perforation performance of a fully clamped circular plate struck by a blunt projectile are obtained. It takes into account both the global response (plate bending) and the localized shear. Based on the estimations of the shear strain and the size of shear hinge, condition for the initiation of an adiabatic shear band is formulated. The effectiveness of the present model is demonstrated by reasonable agreement between the theoretical predictions and the available experimental data for the perforation of Weldox 460E steel plates.     

The large rigid-plastic deformation of a circular cantilever beam subjected to impulsive loading

A quadrantal circular beam subjected to radial impact in its own plane at its tip by a rigid mass is studied on the basis of a large deformation formulation. The procedure for computing this dynamic response is given and numerical examples are shown in order to make a comparison with the results on the basis of small deformation formulation of the same problem.     

Development of double hinge mechanisms in a bent cantilever subjected to an out-of-plane force pulse

In a previous paper [Y. L. , T. X. and S. R. , Double hinge modes in the dynamic response of plastic cantilever beams subjected to step loading. Int. J. Impact Engng 7, 401–413 (1988)] double hinge mechanisms were shown to satisfy all the necessary equations for the initial deformation mechanism of a range of bent cantilevers subjected to an out-of-plane tip force. The present study examines the transient behaviour of such mechanisms when the cantilever is subjected to a force pulse of finite duration. The change in the mechanism as the hinges travel and the partitioning of the dissipation of the input energy are described and compared with the behaviour of a straight cantilever subjected to a force pulse at its tip.     

The transient behavior of diffraction of plane pulse by a circular cylinder

The large-time transient behavior of diffraction of a plane pulse by a circular cylinder is investigated for three different boundary conditions. In each case the behavior is found to be quite different from others. The solutions are expressed in integral forms by Laplace Transforms. The integrals are then evaluated asymptotically for large time or small transform variable. Special attention has been paid to show that the otal field vanishes in the region ahead of the incoming shock front.     

Experimental study of heat transfer in the stagnation zone arising when a plane semibounded jet interacts with a natural-convection stream at a vertical isothermal surface

An experimental study is made of heat transfer in the stagnation zone formed when a plane semibounded jet interacts with a descending free-convection stream at a vertical wall. An attempt was also made to determine experimentally the boundaries of the stagnation zone as a function of the jet parameters and the natural-convection stream.     

Turbulent transition of a laminar boundary layer in the axisymmetric flow of a jet over plane surfaces normal to the stream

Results are presented of experimental investigations of the hydrodynamics of the wall boundary layer on a plate over which an axisymmetric jet flows transversely. The conditions of existence and transition to turbulent of the laminar boundary layer are determined.     

Effect of circular holes on the ratchet limit and crack tip plastic strain range in a centre cracked plate

In this paper a centre cracked plate subjected to cyclic tensile loading and cyclic bending moment is considered. The effect of circular holes drilled in the region of the crack tip on the ratchet limit and crack tip plastic strain range is studied. Direct evaluation of the ratchet limit and crack tip plastic strain range is solved by employing the new Linear Matching Method (LMM). Parametric studies involving hole diameter and location are investigated. The optimum hole location for reducing the crack tip plastic strain range with the least reduction in ratchet limit is identified, and located at a distance 10% of the semi-crack length from the crack tip on the side opposite the ligament for both cyclic tensile loading and cyclic bending moment cases. It is also observed that the optimum location is independent of the hole size for both cyclic loading cases.     

The distribution of stress near the tip of a radial crack at the edge of a circular hole

A Mellin transform technique is used to find an integral equation the solution of which is related to the stress intensity factor and the formation energy of a crack at the edge of a circular hole in an infinite elastic solid. The biaxial loading case is considered in detail and numerical results given.     

A Monte Carlo method to calculate the average solid angle subtended by a right cylinder to a source that is circular or rectangular, plane or thick, at any position and orientation

This note describes the development of a short program for a personal computer to calculate the solid angle subtended by a right cylinder detector to a circular or rectangular, plane or thick source at any position and orientation to the cylinder. The program also calculates the number of hits on the cylinder side and on each end, and the average pathlength through the detector volume (assuming no scattering or absorption). The current performance of personal computers makes it realistic to model the order of 10(9) simulations of radiation emission and achieve accuracies of solid angle estimates typically better than 0.03%.