Interaction of Pressure, End Load, and Twisting Moment for a Rigid-Plastic Circular Tube

1963 ◽  
Vol 30 (3) ◽  
pp. 396-400 ◽  
Author(s):  
Joseph E. Panarelli ◽  
Philip G. Hodge
Keyword(s):  
Circular Cylinder ◽  
Shell Theory ◽  
Circular Tube ◽  
Plastic Material ◽  
Rigid Plastic ◽  
End Effects ◽  
Perfectly Plastic ◽  
Special Cases ◽  
Interaction Surface

A thick-walled circular cylinder acted on by pressure, axial end load, and twisting moment is analyzed under the assumption that end effects are negligible. The locus of all load points (interaction surface) for which unaccelerated flow of a perfectly plastic material can occur is found parametrically. Certain special cases are considered and the results compared with those of shell theory.

The permanent deformation of a cantilever struck transversely at its tip

1955 ◽  
Vol 228 (1175) ◽  
pp. 462-476 ◽  
Keyword(s):  
Plastic Material ◽  
Permanent Deformation ◽  
Rigid Plastic ◽  
Accurate Definition ◽  
Special Cases ◽  
Rigid Plastic Material ◽  
The One ◽  
Definition Of ◽  
Falling Weight ◽  
The Impact

An analysis is given for the deformation of a cantilever made from a rigid-plastic material struck transversely at its tip by a moving mass. Two special cases are found to be of interest: mass of striker large, and mass of striker small. Experiments were carried out on model mildsteel cantilevers under these two extreme conditions: in the one case the striker was a falling weight, in the other a rifle bullet. The theoretical and experimental results are compared, and it is shown that there is good agreement at points remote from the impact, but that prediction of local damage depends on accurate definition of the conditions of striking.

Application of an Eigenfunction Expansion Method in Plasticity

1974 ◽  
Vol 41 (2) ◽  
pp. 448-452 ◽  
Author(s):  
T. Wierzbicki
Keyword(s):  
Plastic Material ◽  
Expansion Method ◽  
Plastic Behavior ◽  
Sensitive Material ◽  
Rigid Plastic ◽  
Simple Method ◽  
Elastic Mode ◽  
Perfectly Plastic ◽  
Eigenfunction Expansion Method ◽  
Expansion Technique

Possibilities of extending the eigenvalue expansion method to dynamic problems for plastic continua and structures are examined. A model of a pseudo strain rate sensitive material is introduced as an approximation to the concept of rigid-perfectly plastic material. A simple method is then developed which parallels the familiar elastic mode expansion technique but yet retains the main features of rigid-plastic behavior. The accuracy of the method is discussed and comparison with previous theories is made. An illustrative example is presented.

scholarly journals Rigid plastic plates at large deformations

1985 ◽  
Vol 7 (3) ◽  
pp. 18-23
Author(s):  
Vu Van The
Keyword(s):  
Large Deformations ◽  
Plastic Material ◽  
Plastic Hinge ◽  
Yield Condition ◽  
Rectangular Plates ◽  
Rigid Plastic ◽  
Hinge Line ◽  
Perfectly Plastic ◽  
Relationship Of ◽  
Line Patterns

The method developed in [8] is applied herein in order to obtain estimations of the load-deflection relationship of the hinge supported rectangular plates acted on by a uniformly distributed loading. The plate is made from rigid perfectly plastic material which yields according to the square yield condition and maximum normal yield condition. the plastic hinge line patterns shown  in figs. 1. 2. are chosen. The obtained results are presented in figs. 4, 5, 6, 8.

The Influence of Blast Characteristics on the Final Deformation of Circular Cylindrical Shells

1956 ◽  
Vol 23 (4) ◽  
pp. 617-624
Author(s):  
P. G. Hodge
Keyword(s):  
Circular Cylindrical Shell ◽  
Plastic Material ◽  
Practical Importance ◽  
Yield Condition ◽  
Flow Rule ◽  
Analytic Approximation ◽  
Rigid Plastic ◽  
End Effects ◽  
Maximum Deformation ◽  
Method Of Solution

Abstract The final maximum deformation of a reinforced circular cylindrical shell caused by a briefly applied, intense loading is considered. The maximum deformation is obtained in a form which requires a double quadrature of the pressure where the limits of the integration are determined from side conditions. Attempts are made to find a simple analytic approximation, but the attempts are unsuccessful for loads of practical importance. A straightforward graphical-numerical method of solution is devised. Several examples are considered in support of the conclusions. The shell is assumed to be infinitely long, so that end effects may be neglected. The load is assumed to be applied to the entire shell simultaneously. The shell is assumed a perfect cylinder, and the reinforcements are taken as rigid. Finally, the shell is assumed to be made of an ideal rigid-plastic material which satisfies a certain simplified yield condition and the associated flow rule.

General Properties of Yield-Point Load Surfaces

1968 ◽  
Vol 35 (1) ◽  
pp. 107-110 ◽  
Author(s):  
P. G. Hodge ◽  
Chang-Kuei Sun
Keyword(s):  
Strain Rate ◽  
Yield Point ◽  
Yield Surface ◽  
Plastic Material ◽  
Point Load ◽  
Perfectly Plastic ◽  
Plastic Mechanism ◽  
Rate Vector ◽  
Strain Rate Vector ◽  
Interaction Surface

A structure made of a rigid perfectly plastic material and subjected to more than one independent load is considered. A mode vector is defined for any plastic mechanism and shown to have the same properties relative to the yield-point load interaction surface that the strain-rate vector has to the material yield surface. An application to a circular plate under two independent loads leads to close bounds on the interaction curve.

scholarly journals A new displacement bound technique for rigid plastic continua subjectet to strong dynamic loading at large deflections II.

1987 ◽  
Vol 9 (3) ◽  
pp. 23-30
Author(s):  
Vu Van The ◽  
Tran Ba Tinh
Keyword(s):  
Space Variable ◽  
Shape Function ◽  
Plastic Material ◽  
Yield Condition ◽  
Time Function ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Previous Solution ◽  
Admissible Displacement ◽  
Strong Dynamic

The method developed in [ 1] is applied herein in order to obtain lower hound to large displacements of the hinge supported circular plate acted on by impulsively, uniformly distributed loading. The plate is made from rigid and perfectly plastic material which yields according to the yield condition shown in fig- 1· The lower bound (1.21) is obtained when the dynamically admissible displacement and velocity are chosen in separated variable form which is a scalar time function multiplied by a vector shape function of space variable (1.13). In the case when W, Ẇ * are chosen in form (1.22). [comparison of the obtained estimate Eq (1.24) with previous solution of the same problem [1], upper bound [2] and experimental date [3] are presented in fig. 2

scholarly journals Plastic forming processes of transverse non-homogeneous composite metallic sheets

2021 ◽  
Vol 11 (1) ◽  
pp. 294-302
Author(s):  
Gal Davidi
Keyword(s):  
Inner Core ◽  
Plastic Material ◽  
Radial Solution ◽  
Algebraic Differential Equation ◽  
Forming Process ◽  
Perfectly Plastic ◽  
Plastic Forming ◽  
Validity Limit ◽  
Significant Achievement

Abstract In this work an analysis of the radial stress and velocity fields is performed according to the J 2 flow theory for a rigid/perfectly plastic material. The flow field is used to simulate the forming processes of sheets. The significant achievement of this paper is the generalization of the work by Nadai & Hill for homogenous material in the sense of its yield stress, to a material with general transverse non-homogeneity. In Addition, a special un-coupled form of the system of equations is obtained where the task of solving it reduces to the solution of a single non-linear algebraic differential equation for the shear stress. A semi-analytical solution is attained solving numerically this equation and the rest of the stresses term together with the velocity field is calculated analytically. As a case study a tri-layered symmetrical sheet is chosen for two configurations: soft inner core and hard coating, hard inner core and soft coating. The main practical outcome of this work is the derivation of the validity limit for radial solution by mapping the “state space” that encompasses all possible configurations of the forming process. This configuration mapping defines the “safe” range of configurations parameters in which flawless processes can be achieved. Several aspects are researched: the ratio of material's properties of two adjacent layers, the location of layers interface and friction coefficient with the walls of the dies.

On the Conditions to Prevent Plastic Shakedown of Structures: Part I—Theory

1993 ◽  
Vol 60 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Castrenze Polizzotto
Keyword(s):  
Mechanical Load ◽  
Plastic Material ◽  
Perfectly Plastic ◽  
Shakedown Theory ◽  
Elastic Perfectly Plastic ◽  
Plastic Shakedown ◽  
Steady Load

For a structure of elastic perfectly plastic material subjected to a given cyclic (mechanical and/or kinematical) load and to a steady (mechanical) load, the conditions are established in which plastic shakedown cannot occur whatever the steady load, and thus the structure is safe against the alternating plasticity collapse. Static and kinematic theorems, analogous to those of classical shakedown theory, are presented.

Elasto-Plastic Coupled Temperature-Displacement Finite Element Analysis of Two-Dimensional Rolling-Sliding Contact With a Translating Heat Source

1991 ◽  
Vol 113 (1) ◽  
pp. 93-101 ◽  
Author(s):  
S. M. Kulkarni ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Finite Element ◽  
Half Space ◽  
Plastic Material ◽  
Element Model ◽  
Rolling Contact ◽  
Two Dimensional ◽  
Element Analysis ◽  
Element Mesh ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

The present paper, describes a transient translating elasto-plastic thermo-mechanical finite element model to study 2-D frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a non-uniform thermo-mechanical distribution across the surface of an elasto-plastic half space. The half space is represented by a two dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermo-physical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on 1) the temperature gradients and 2) the magnitudes of the normal and tangential tractions.

Shakedown Limit Load Determination for a Kinematically Hardening 90-Degree Pipe Bend Subjected to Constant Internal Pressure and Cyclic Bending

2007 ◽  
Author(s):  
Hany F. Abdalla ◽  
Mohammad M. Megahed ◽  
Maher Y. A. Younan
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Plastic Material ◽  
Kinematic Hardening ◽  
Limit Load ◽  
Material Behavior ◽  
Pipe Bend ◽  
Cyclic Bending ◽  
Perfectly Plastic ◽  
Shakedown Limit

A simplified technique for determining the shakedown limit load of a structure employing an elastic-perfectly-plastic material behavior was previously developed and successfully applied to a long radius 90-degree pipe bend. The pipe bend is subjected to constant internal pressure and cyclic bending. The cyclic bending includes three different loading patterns namely; in-plane closing, in-plane opening, and out-of-plane bending moment loadings. The simplified technique utilizes the finite element method and employs small displacement formulation to determine the shakedown limit load without performing lengthy time consuming full cyclic loading finite element simulations or conventional iterative elastic techniques. In the present paper, the simplified technique is further modified to handle structures employing elastic-plastic material behavior following the kinematic hardening rule. The shakedown limit load is determined through the calculation of residual stresses developed within the pipe bend structure accounting for the back stresses, determined from the kinematic hardening shift tensor, responsible for the translation of the yield surface. The outcomes of the simplified technique showed very good correlation with the results of full elastic-plastic cyclic loading finite element simulations. The shakedown limit moments output by the simplified technique are used to generate shakedown diagrams of the pipe bend for a spectrum of constant internal pressure magnitudes. The generated shakedown diagrams are compared with the ones previously generated employing an elastic-perfectly-plastic material behavior. These indicated conservative shakedown limit moments compared to the ones employing the kinematic hardening rule.

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