The Yielding Behavior of Particulate Media

1973 ◽  
Vol 10 (3) ◽  
pp. 341-362 ◽  
Author(s):  
S. Frydman ◽  
J. G. Zeitlen ◽  
I. Alpan
Keyword(s):  
Yield Point ◽  
Stress Path ◽  
Yield Function ◽  
Normal Stresses ◽  
Test Program ◽  
Stress Strain ◽  
Particulate Media ◽  
Yielding Behavior ◽  
Interparticle Friction ◽  
Von Mises

This paper presents a discussion of the yielding behavior of particulate media during shearing, based on the results of a laboratory investigation of the stress–strain properties of samples of glass microspheres. The test program, carried out on hollow cylinder specimens, studied the effect of functions of the three stress invariants on the stress–strain behavior.It is suggested that a 'yield' point may be defined, below which relatively little interparticle slippage occurs. Below this yield point, stress–strain relations under any particular stress-path may be predicted from superposition of isotropic and deviatoric components. An initial yield point is defined which is shown to occur at a constant ratio of octahedral shear to normal stresses, so obeying an extended Von Mises type criterion.With regards to the post-yield-point behavior, an expression is developed for the yielding behavior, based on an assumed mechanism of energy dissipation within the mass. This yield relation expresses the lack of normality between the strain increment vector and the yield function, known empirically to exist in granular materials, and shows that the deviation from normality is constant, and related to the true angle of interparticle friction, [Formula: see text].

MODELING OF THE STRESS-STRAIN STATE OF A TRANSPORT TUNNEL UNDER LOAD AS A MEASURE TO REDUCE OPERATIONAL RISKS TO TRANSPORTATION FACILITIES

2020 ◽  
Vol 3 (8) ◽  
pp. 28-34
Author(s):  
N. V. IVANITSKAYA ◽  
◽  
A. K. BAYBULOV ◽  
M. V. SAFRONCHUK ◽  
◽  
...  
Keyword(s):  
Strain State ◽  
Moving Load ◽  
Element Model ◽  
Transport Infrastructure ◽  
Design Stage ◽  
Surface Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Operational Risks ◽  
Von Mises

In many countries economic policy has been paying increasing attention to the modernization and development of transport infrastructure as a measure of macroeconomic stimulation. Tunnels as an important component of transport infrastructure save a lot of logistical costs. It stimulates increasing freight and passenger traffic as well as the risks of the consequences of unforeseen overloads. The objective of the paper is to suggest the way to reduce operational risks of unforeseen moving load by modeling of the stress-strain state of a transport tunnel under growing load for different conditions and geophysical parameters. The article presents the results of a study of the stress-strain state (SSS) of a transport tunnel exposed to a mobile surface load. Numerical experiments carried out in the ANSYS software package made it possible to obtain diagrams showing the distribution of equivalent stresses (von Mises – stresses) according to the finite element model of the tunnel. The research results give grounds to assert that from external factors the stress state of the tunnel is mainly influenced by the distance to the moving load. The results obtained make it possible to predict in advance the parameters of the stress-strain state in the near-contour area of the tunnel and use the results in the subsequent design of underground facilities, as well as to increase their reliability and operational safety. This investigation gives an opportunity not only to reduce operational risks at the design stage, but to choose an optimal balance between investigation costs and benefits of safety usage period prolongation.

Elasto-Plastic Analysis of Reissner-Mindlin Plates

1990 ◽  
Vol 43 (5S) ◽  
pp. S40-S50 ◽  
Author(s):  
Panayiotis Papadopoulos ◽  
Robert L. Taylor
Keyword(s):  
Yield Function ◽  
Rate Equations ◽  
Test Problems ◽  
Field Equations ◽  
Element Analysis ◽  
Linear Hardening ◽  
Nonlinear Version ◽  
Plastic Analysis ◽  
Von Mises ◽  
Predictor Corrector

A finite element analysis of elasto-plastic Reissner-Mindlin plates is presented. The discrete field equations are derived from a nonlinear version of the Hu-Washizu variational principle. Associative plasticity, including linear hardening, is employed by means of a generalized von Mises-type yield function. A predictor/corrector scheme is used to integrate the plastic constitutive rate equations. Numerical simulations are conducted for a series of test problems to illustrate performance of the formulation.

Definition of the yield point in plasticity and its effect on the shape of the yield locus

1966 ◽  
Vol 1 (4) ◽  
pp. 331-338 ◽  
Author(s):  
T C Hsu
Keyword(s):  
Yield Point ◽  
Experimental Work ◽  
Strain Curve ◽  
Yield Locus ◽  
Experimental Results ◽  
Stress Strain Curve ◽  
Proportional Limit ◽  
Stress Strain ◽  
Small Section ◽  
Definition Of

Three different definitions of the yield point have been used in experimental work on the yield locus: proportional limit, proof strain and the ‘yield point’ by backward extrapolation. The theoretical implications of the ‘yield point’ by backward extrapolation are examined in an analysis of the loading and re-loading stress paths. It is shown, in connection with experimental results by Miastkowski and Szczepinski, that the proportional limit found by inspection is in fact a point located by backward extrapolation based on a small section of the stress-strain curve, near the elastic portion of the curve. The effect of different definitions of the yield point on the shape of the yield locus and some considerations for the choice between them are discussed.

A Two-Dimensional Linear Assumed Strain Triangular Element for Finite Deformation Analysis

2005 ◽  
Vol 73 (6) ◽  
pp. 970-976 ◽  
Author(s):  
Fernando G. Flores
Keyword(s):  
Finite Deformation ◽  
Degrees Of Freedom ◽  
Yield Function ◽  
Triangular Element ◽  
Deformation Analysis ◽  
Elastic Model ◽  
Stress Strain ◽  
Metric Tensor ◽  
Assumed Strain ◽  
Non Linear

An assumed strain approach for a linear triangular element able to handle finite deformation problems is presented in this paper. The element is based on a total Lagrangian formulation and its geometry is defined by three nodes with only translational degrees of freedom. The strains are computed from the metric tensor, which is interpolated linearly from the values obtained at the mid-side points of the element. The evaluation of the gradient at each side of the triangle is made resorting to the geometry of the adjacent elements, leading to a four element patch. The approach is then nonconforming, nevertheless the element passes the patch test. To deal with plasticity at finite deformations a logarithmic stress-strain pair is used where an additive decomposition of elastic and plastic strains is adopted. A hyper-elastic model for the elastic linear stress-strain relation and an isotropic quadratic yield function (Mises) for the plastic part are considered. The element has been implemented in two finite element codes: an implicit static/dynamic program for moderately non-linear problems and an explicit dynamic code for problems with strong nonlinearities. Several examples are shown to assess the behavior of the present element in linear plane stress states and non-linear plane strain states as well as in axi-symmetric problems.

On the Impact Behavior of a Material With a Yield Point

1949 ◽  
Vol 16 (1) ◽  
pp. 39-52
Author(s):  
Merit P. White
Keyword(s):  
Yield Stress ◽  
Yield Point ◽  
Impact Behavior ◽  
Longitudinal Impact ◽  
Stress Strain ◽  
California Institute Of Technology ◽  
Static Yield ◽  
Institute Of Technology ◽  
Probable Nature ◽  
The Impact

Abstract An analysis of longitudinal impact tests that were made by Drs. D. S. Clark and P. E. Duwez at the California Institute of Technology on an iron and a steel with definite yield points is described. From this analysis is deduced the probable nature of the dynamic stress-strain relations for such materials. These appear to differ greatly from the static stress-strain relations, unlike the case for materials without yield points. As pointed out by Duwez and Clark, the upper yield stress for undeformed material is several times as great under impact as the static yield stress. The present analysis indicates that under impact, the material with a definite yield point is made harder at a given deformation, and ruptures at a higher (engineering) stress and smaller strain than when loaded statically. The critical impact velocity, defined as that at which nearly instantaneous failure occurs in tension, is discussed, and the factors upon which it depends are given.

An Application of Incremental Plasticity Theory to Fatigue Life Prediction of Steels

1991 ◽  
Vol 113 (4) ◽  
pp. 404-410 ◽  
Author(s):  
W. R. Chen ◽  
L. M. Keer
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Kinematic Hardening ◽  
Yield Condition ◽  
Strain Curve ◽  
Fatigue Life Prediction ◽  
304 Stainless Steel ◽  
Flow Rule ◽  
Stress Strain ◽  
Von Mises

An incremental plasticity model is proposed based on the von-Mises yield condition, associated flow rule, and nonlinear kinematic hardening rule. In the present model, fatigue life prediction requires only the uniaxial cycle stress-strain curve and the uniaxial fatigue test results on smooth specimens. Experimental data of 304 stainless steel and 1045 carbon steel were used to validate this analytical model. It is shown that a reasonable description of steady-state hysteresis stress-strain loops and prediction of fatigue lives under various combined axial-torsional loadings are given by this model

Influence of Anisotropic Yield Functions on Parameters of Yoshida-Uemori Model

2013 ◽  
Vol 554-557 ◽  
pp. 2440-2452 ◽  
Author(s):  
Hirotaka Kano ◽  
Jiro Hiramoto ◽  
Toru Inazumi ◽  
Takeshi Uemori ◽  
Fusahito Yoshida
Keyword(s):  
Effective Strain ◽  
Yield Function ◽  
Strain Response ◽  
Material Parameters ◽  
International Conference ◽  
Polynomial Type ◽  
Calculated Stress ◽  
Yield Functions ◽  
Order Polynomial ◽  
Von Mises

Yoshida-Uemori model (Y-U model) can be used with any types of yield functions. The calculated stress strain response will be, however, different depending on the chosen yield function if the yield function and the effective strain definition are inappropriate. Thus several modifications to Y-U model were proposed in the 10th International Conference on Technology of Plasticity. It was ascertained that in the modified Y-U model, the same set of material parameters can be used with von Mises, Hill’s 1948, and Hill’s 1990 yield function. In this study, Yld2000-2d and Yoshida’s 6th-order polynomial type 3D yield function were examined and it was clarified that the same set of Y-U parameters can be used with these yield functions.

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