scholarly journals Discussion: “Increase of Stress With Permanent Strain and Stress-Strain Relations in Plastic State for Copper Under Combined Stresses” (Davis, E. A., 1943, ASME J. Appl. Mech., 10, pp. A187–A196)

1944 ◽  
Vol 11 (3) ◽  
pp. A190
Author(s):  
R. G. Sturm
Keyword(s):  
Plastic State ◽  
Stress Strain ◽  
Permanent Strain ◽  
Combined Stresses

Increase of Stress With Permanent Strain and Stress-Strain Relations in the Plastic State for Copper Under Combined Stresses

1943 ◽  
Vol 10 (4) ◽  
pp. A187-A196
Author(s):  
E. A. Davis
Keyword(s):  
Internal Pressure ◽  
Axial Load ◽  
Plastic State ◽  
Plastic Strains ◽  
Permanent Strain ◽  
Axial Tension ◽  
Combined Stresses ◽  
Hollow Cylinders ◽  
Annealed Copper ◽  
Principal Strains

Abstract Annealed-copper specimens in the shape of hollow cylinders have been tested by subjecting them to combined axial tension and internal pressure. A given ratio of the internal pressure to the axial load has been maintained throughout each test, but for different tests this ratio was changed so as to cover the range from pure tension at one extreme to the case of equal biaxial tensions at the other. The results have been used to study the manner in which the plastic strains increase with increasing stress and also to determine the relationships between the three principal strains at any instant during the test. Also, a few observations are made on the types of fracture obtained under various conditions of loading.

Mechanisms Governing the Inelastic Deformation of Cortical Bone

2005 ◽  
Vol 873 ◽  
Author(s):  
C. Mercer ◽  
R. Wang ◽  
A. G. Evans
Keyword(s):  
Cortical Bone ◽  
Inelastic Deformation ◽  
Collagen Fibrils ◽  
Strain Response ◽  
Flexural Test ◽  
Test Protocol ◽  
Stress Strain ◽  
Permanent Strain ◽  
Nano Scale ◽  
Transverse Strains

AbstractTo understand the inelastic response of bone, a two-part investigation has been conducted. In the first, a flexural test protocol has been designed and implemented that monitors the axial and transverse strains on both the tensile and compressive surfaces of cortical bone. The results are used to assess the relative contributions of dilatation and shear to the inelastic deformation. Unload/reload tests have characterized the hysteresis and provided insight about the mechanisms causing the strain. These tests reveal strain healing attributed to sacrificial bonds. The second part devises a model for the stress/strain response, based on a recent assessment of the nano-scale organization of the collagen fibrils and mineral platelets. The model rationalizes the inelastic deformation in tension, as well as the permanent strain and hysteresis.

scholarly journals DETERMINATION OF STRESS-STRAIN STATE OF THE BODY SURFACE OR ITS AREA IN CASE OF PERFECT PLASTICITY AT GIVEN STRESS AND DISPLACEMENT VECTORS

2020 ◽  
Vol 2 ◽  
pp. 201-209
Author(s):  
Anvar I. Chanyshev ◽  
Ilgizar M. Abdulin ◽  
Olga A. Lukyashko
Keyword(s):  
Body Surface ◽  
Strain State ◽  
Rapid Assessment ◽  
Strain Tensor ◽  
The Body ◽  
Plastic State ◽  
Cauchy Stress ◽  
Stress Strain ◽  
Stress Strain State ◽  
Displacement Vectors

Ideally plastic state of material under conditions of Mises plasticity, proportionality of stress and strain deviators (deformation theory of plasticity) and elastic volume change is considered. Given the Cauchy stress and displacement vectors specified on the body surface (with indicated state) or its area, all six components of the stress tensor, all six components of the strain tensor, and also three components of the rotation vector are restored on this surface. This method for determining the stress-strain state can be related to the methods of rapid assessment of the structure state (body surface), since differential equations inside the body are not involved.

scholarly journals Finite element analysis of elastic-plastic state of crack at the interface between infinite plane and circular inclusion

2019 ◽  
pp. 20-23
Author(s):  
V. J. Adlucky ◽  
A. Yu. Hodes ◽  
V. V. Loboda
Keyword(s):  
Strain State ◽  
Circular Inclusion ◽  
Plastic State ◽  
Isotropic Hardening ◽  
Infinite Plane ◽  
Stress Strain ◽  
Elastic Plastic ◽  
Stress Strain State ◽  
Crack Faces ◽  
Plastic Stress

The problem on determining of elastic-plastic stress-strain state of infinite plane with a circular inclusion made from another material and an arc crack at the interface under action of arbitrary mechanical loadings applied at infinity is considered using the FEM approach. The problem is resolved within the framework of contact model for which the possibility of appearance of contact macrozones between crack faces is assumed. The isotropic hardening of materials with bilinear approximation of stress-strain curves is considered. The infinite plane is modeled by square domain whose size is of an order of magnitude greater than inclusion diameter. Contact interaction of crack faces is simulated using gap elements. To obtain the energy release rate the J-integrals are calculated along several closed contours around the crack tips. The comparison of obtained results with available analytical solutions for linear elasticity shows that insignificant differences take place during transformation from pure elastic to elastic-plastic stress-strain state.

scholarly journals Mechanical Properties and Their Quantification Particularly When Transiting from Elastic to Plastic State on Materials Cut by AWJ

2018 ◽  
Vol 15 (2) ◽  
pp. 52-57
Author(s):  
Marek Šafář ◽  
Marta Harničárová ◽  
Milena Kušnerová ◽  
Jan Valíček
Keyword(s):  
Surface Topography ◽  
Tool Material ◽  
Abrasive Waterjet ◽  
Plastic State ◽  
Mechanical Resistance ◽  
Stress Strain ◽  
Flexible Tool ◽  
Geometrical Properties ◽  
Material Systems ◽  
Theoretical Results

Abstract Mechanical behaviour of materials during and after cutting process is depended on various factors. Surface topography is set of factors including mechanical and geometrical properties. From the surface topography, it is possible to resolve the transition from ideally elastic to quasi-elastic and plastic stress-strain states, particularly by finding a neutral plane of cut, where the compressive and tensile components are still in equilibrium. The paper solves the problem of the nonexistence of a new method for calculation of dynamics of stress-deformation states of deformation tool-material systems including the construction of stress-strain diagrams. The presented solution focuses on explaining the mechanical behavior of materials after cutting by abrasive waterjet technology (AWJ) which is a flexible tool accurately responding to the mechanical resistance of the material according to the accurately determined shape and roughness of machined surfaces. Theoretical results were compared by a certified laboratory VUHZ.

scholarly journals Numerical Investigation of Relationship between Bursting Proneness and Mechanical Parameters of Coal

2021 ◽  
Vol 2021 ◽  
pp. 1-28
Author(s):  
Hongwei Wang ◽  
Jiaqi Song ◽  
Zeliang Wang ◽  
Yue Zhang ◽  
Shaozhen Zhang ◽  
...  
Keyword(s):  
Numerical Model ◽  
Safety Concern ◽  
Distribution Functions ◽  
Plastic State ◽  
Shear Strain Rate ◽  
Mechanical Parameters ◽  
Stress Strain ◽  
Soft Coal ◽  
Geological Conditions ◽  
Coal Bursts

As one of the most catastrophic dynamic hazards in underground coal mines, coal bursts have been a major safety concern around the world for many years. Although the coal bursts can occur in all cases of hard to soft coal if the right stress environment is created, the occurrence of coal bursts is closely related to the intrinsic mechanical properties of coal, such as the bursting proneness. In this study, a total of 27 coal specimens are selected in the open literature studies to obtain a group of fundament data, such as the mechanical parameters, four bursting proneness indices, stress-strain curves, and their geological conditions where the specimens were taken. The relationship between bursting proneness indices and the cohesion of the coal specimens is established by numerically fitting the stress-strain curves and theoretically deduction. By taking into account the coal heterogeneity, eight probability distribution functions are employed to assignment nonuniform cohesion to the numerical model and to study the influence of heterogeneity on bursting proneness. The results reveal that the coal cohesion, which combines the common advantages of the four proneness indices, can be used as bursting proneness index. In the research of heterogeneity, the coal bursting proneness will decrease with the increasing of cohesion scatter degree. The larger the cohesion scatter degree increase is, the lower the bursting proneness will be. The failure of coal specimen is more and more severe with the decrease of cohesion scatter degree. In addition, this paper provides two methods for assigning heterogeneous parameters to the numerical model. The contours of shear strain rate and plastic state between homogeneous and heterogeneous coal specimens are compared to study the failure types of coal specimens and to reveal the mechanism of violent failure in coal bursts.

Mechanisms Governing the Inelastic Deformation of Cortical Bone

2005 ◽  
Vol 874 ◽  
Author(s):  
C. Mercer ◽  
R. Wang ◽  
A. G. Evans
Keyword(s):  
Cortical Bone ◽  
Inelastic Deformation ◽  
Collagen Fibrils ◽  
Strain Response ◽  
Flexural Test ◽  
Test Protocol ◽  
Stress Strain ◽  
Permanent Strain ◽  
Nano Scale ◽  
Transverse Strains

AbstractTo understand the inelastic response of bone, a two-part investigation has been conducted. In the first, a flexural test protocol has been designed and implemented that monitors the axial and transverse strains on both the tensile and compressive surfaces of cortical bone. The results are used to assess the relative contributions of dilatation and shear to the inelastic deformation. Unload/reload tests have characterized the hysteresis and provided insight about the mechanisms causing the strain. These tests reveal strain healing attributed to sacrificial bonds. The second part devises a model for the stress/strain response, based on a recent assessment of the nano-scale organization of the collagen fibrils and mineral platelets. The model rationalizes the inelastic deformation in tension, as well as the permanent strain and hysteresis.

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