STRESS CONCENTRATION NEAR THE ELLIPSOIDAL INCLUSION IN THE BODY AS A RESULT OF THE PRELIMINARY PLASTIC DEFORMATION

The article considers a crack in the form of a narrow cut with a certain cfn at the cut out in an unbounded plate. The characteristics of the mechanical state of this system under uniaxial loading are determined: the stress concentration coefficient, the crack-driving force, and the energy of a solid with a crack. The elastic energy expenditure during crack propagation is determined. The general regularities of the mechanical state of a solid with a crack, not necessary having the form of an ellipse, are revealed. An important parameter of a crack is the curvature at the tip. It is shown that the Griffiths crack does not actually have a singularity at the tip. The stress strain state of the plate with an elliptical crack is identical to the same of the plate with a focus of homogeneous plastic deformation.

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Effect of preliminary plastic deformation on the destruction of composite material

Metal Science and Heat Treatment ◽

10.1007/bf00802261 ◽

1989 ◽

Vol 31 (7) ◽

pp. 485-487

Author(s):

M. A. Krishtal ◽

Ya. A. Gokhberg ◽

V. I. Frolov ◽

L. E. �pshtein ◽

N. V. Volokhova

Keyword(s):

Plastic Deformation ◽

Composite Material ◽

Preliminary Plastic Deformation

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INFLUENCE OF THE HOLE-SIDE PLASTIC DEFORMATION AS A RESULT OF THE STRESS CONCENTRATION ON THE ACCURACY OF RESIDUAL WELDING STRESS MEASUREMENT BY SMALL BLIND HOLE RELAXATION METHOD AND ITS MODIFICATION

Welding for Challenging Environments ◽

10.1016/b978-0-08-031866-0.50028-7 ◽

1986 ◽

pp. 253-262

Author(s):

Guang Duo Li ◽

Bai Liang Liu ◽

Ben Yuan Li

Keyword(s):

Plastic Deformation ◽

Stress Concentration ◽

Stress Measurement ◽

Relaxation Method ◽

Residual Welding Stress ◽

Welding Stress ◽

Blind Hole ◽

Residual Welding

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Dependence of the preliminary plastic deformation on the curves of chromium-nickel steel deformation

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/939/1/012061 ◽

2020 ◽

Vol 939 ◽

pp. 012061

Author(s):

V A Popov

Keyword(s):

Plastic Deformation ◽

Nickel Steel ◽

Preliminary Plastic Deformation

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Analysis of the Influence of Fluid Flow on the Plasticity of Porous Rock Under an Axially Symmetric Punch

Society of Petroleum Engineers Journal ◽

10.2118/4243-pa ◽

1974 ◽

Vol 14 (03) ◽

pp. 271-278 ◽

Cited By ~ 3

Author(s):

Milos Kojic ◽

J.B. Cheatham

Keyword(s):

Plastic Deformation ◽

Porous Medium ◽

Porous Media ◽

Fluid Flow ◽

Pressure Gradient ◽

Stress Tensor ◽

Unit Volume ◽

Fluid Pressure ◽

The Body ◽

Axially Symmetric

Introduction A number of problems occur in the fields of drilling and rock mechanics for which consideration must be given to the interaction of fluid flow and rock deformation. Such problems include those of borehole stability, chip removal from under a drill bit, drilling in the presence of a fluid pressure gradient between the drilling fluid and formation fluid, and drilling by use of hydraulic jets. We have recently developed a general theory of the influence of fluid pressure gradients and gravity on the plasticity of porous media. The solution of the problem considered here serves as an example of the application of that theory. The illustrative problem is to determine the load required on a flat problem is to determine the load required on a flat axially symmetric punch for incipient plasticity of the porous medium under the punch when fluid flows through the bottom face of the punch. The rock is assumed to behave as a Coulomb plastic material under the influence of body forces plastic material under the influence of body forces due to fluid pressure gradients and gravity. Numerical methods that have been used by Cox et al. for analyzing axially symmetric plastic deformation in soils with gravity force are applied to the problem considered here. Involved is an iterative process for determining the slip lines. The fluid flow field ‘used for calculating the fluid pressure gradient is based upon the work by Ham pressure gradient is based upon the work by Ham in his study of the potential distribution ahead of the bit in rotary drilling. The effective stresses in the porous rock and the punch force for incipient plasticity are computed in terms of the fluid plasticity are computed in terms of the fluid pressure and the cohesive strength and internal pressure and the cohesive strength and internal friction of the rock. PLASTICITY OF POROUS MEDIA PLASTICITY OF POROUS MEDIA A recently developed general theory of plasticity of porous media under the influence of fluid flow is summarized in this section. The equation of motion for the porous solid for the case of incipient plastic deformation reduces to the following equilibrium equation:(1) where Ts is the partial stress tensor of the solid; Fs is the body force acting on the solid per unit volume of the solid material; P is the interaction force between the solid and the fluid; and is the porosity, which is defined as the ratio of the pore porosity, which is defined as the ratio of the pore volume to the total volume of the solid-fluid mixture. The partial stress tensor Ts can be considered as the effective stress tensor that is used in sod mechanics. With the acceptance of the effective stress principle defined in Ref. 5, the yield function, f, in the following form is satisfied for plastic deformation of the porous medium. plastic deformation of the porous medium.(2) where EP is the plastic strain tensor and K and the work-hardening parameter. From the equation of motion for the fluid, the interaction force P can be expressed in the form(3) where is the inertial force of the fluid per unit volume of the mixture and F is the body force acting on the fluid per unit volume of fluid. For the case of incipient plastic deformation the solid can be considered static (velocities of the solid particles are zero), and the problem of determining particles are zero), and the problem of determining the fluid flow field is the one usually analyzed in petroleum engineering. petroleum engineering. Consider a flow of be fluid such that the inertial forces of the fluid can be neglected and assume that Darcy's law is applicable. SPEJ P. 271

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MECHANICAL STRESS MAY CAUSE THE TEAR OF THE LABRUM IN ACETABULAR DYSPLASIA

Journal of Musculoskeletal Research ◽

10.1142/s021895770400120x ◽

2004 ◽

Vol 08 (01) ◽

pp. 35-41

Author(s):

Hirotaka Sano ◽

Norikazu Yamada ◽

Shingo Maeda

Keyword(s):

Stress Concentration ◽

Mechanical Stress ◽

Acetabular Dysplasia ◽

The Body ◽

Von Mises Stress ◽

Center Edge ◽

Dimensional Finite Element ◽

Von Mises ◽

Distal Border ◽

The Relationship

In the current study, using the arthrogram, we developed two-dimensional finite element (FE) models of the human hip joint. To clarify the relationship between the stress distribution and the degree of acetabular dysplasia, three FE models were established and analyzed. The models varied only in the degree of the bony covering of the femoral head; i.e. the center-edge (CE) angle=20, 10, 0 degrees. An edge load (x=0 N, y=600 N) was then applied on the distal border of the femur to simulate the bearing of the body weight. In the CE=20 degree model, no definite stress concentration was seen at the site of the labrum. On the other hand, the stress concentration was seen from the attachment of the labrum to the superior aspect of the acetabulum in the CE=0 degree model. The site of stress concentration clearly corresponded to the lesions where the acetabular rim pathologies were seen in the clinical practice. Moreover, we found that the Von Mises stress increases dramatically with decreasing the CE angle at the attachment of the labrum. In the dysplastic hip, the mechanical stress increases significantly at the supero-lateral aspect of the acetabulum, which eventually leads to the tearing or detachment of the labrum.

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