scholarly journals POROUS RIGID-PLASTIC MATERIALS CONTAINING RIGID INCLUSIONS - YIELD FUNCTION, PLASTIC POTENTIAL, AND VOID NUCLEATION

1978 ◽  
pp. 357-364 ◽  
Author(s):  
A.L. Gurson
Keyword(s):  
Void Nucleation ◽  
Yield Function ◽  
Rigid Plastic ◽  
Plastic Materials ◽  
Plastic Potential

On the Plastic Flow of Coulomb Solids Beyond Original Failure

1959 ◽  
Vol 26 (4) ◽  
pp. 599-602
Author(s):  
A. W. Jenike ◽  
R. T. Shield
Keyword(s):  
Velocity Field ◽  
Stress Field ◽  
Plastic Flow ◽  
Yield Function ◽  
Two Dimensions ◽  
Rigid Plastic ◽  
Variable Yield ◽  
Angle Of Friction ◽  
Effective Angle

Abstract Principles developed for rigid-plastic solids exhibiting Coulomb’s properties are adapted to the analysis of flow beyond original failure. A variable yield function is proposed to account for the changes of cohesion during flow and equations are evolved for the stress field in two dimensions. It is shown that, while in the stress field an effective angle of friction larger than the actual angle of friction is mandatory for these materials, in the velocity field the materials can be assumed incompressible.

Places and Causes of Mismanaged Plastic Materials in the Life Cycle of Flexible Plastic Packaging Based on Mechanical Recycling Context

2021 ◽  
Vol 888 ◽  
pp. 129-138
Author(s):  
Munzir Hadengganan ◽  
Djoko Sihono Gabriel
Keyword(s):  
Life Cycle ◽  
Plastic Material ◽  
Life Cycles ◽  
Plastic Waste ◽  
Production Cycle ◽  
Mechanical Recycling ◽  
Rigid Plastic ◽  
Plastic Packaging ◽  
Quality Degradation ◽  
Plastic Materials

Plastic waste has become a big issue in the world for its large amount of plastic waste in the sea. Most of the plastic waste is plastic packaging which consists of flexible and rigid plastic packaging. This research discusses flexible plastic packaging. Until now, most researches on the loss of plastic materials discuss how to manage plastic waste disposal once it has been used by community: only a few discuss production cycle: while none of them discusses flexible plastic packaging area. This research aims to examine the number of mismanaged materials throughout flexible plastic packaging life cycle using a combination of Material Flow Analysis (MFA) and Life Cycle Analysis (LCA). Based on the literature review, interviews and observations conducted by the author to all stakeholders in the life cycle of flexible plastic packaging, mismanagement of plastic material occurred in each cycle, mostly caused by quality degradation of flexible plastic that could cause plastic waste was not acceptable in the mechanical recycle. The results of this study show that: (1) mismanaged material occurred in all cycles throughout the life cycles of flexible plastic packaging, (2) quality degradation is the main caused of mismanaged material in several cycles, and (3) the mismanaged materials in the life cycle of flexible plastic packaging were 98.29%.

Plastic flow in extrusion and drawing through conical and wedge-shaped dies: Prediction of central bursting

2006 ◽  
Vol 220 (8) ◽  
pp. 1201-1210 ◽  
Author(s):  
S N Samy ◽  
Ch A R Saleh ◽  
A R Ragab
Keyword(s):  
Experimental Data ◽  
Plane Strain ◽  
Deformation Zone ◽  
Hydrostatic Stress ◽  
Plastic Instability ◽  
Instability Criterion ◽  
Fracture Criteria ◽  
Rigid Plastic ◽  
Stress Criterion ◽  
Plastic Materials

In this article, the plastic flowfields for extrusion and drawing - for rigid plastic materials forced through conical and wedge-shaped dies - are analysed on the basis of Shield's work. A modification to Shield's analysis is developed to account for the redundant deformation. Solutions for axisymmetric and plane strain flows are given. The total forces estimated for both drawing and extrusion operations are compared favourably with available experimental data. On the basis of the present modified Shield's analysis, expressions for the stresses within the die are then derived. These expressions are then employed to predict central bursting by applying two fracture criteria, namely: the hydrostatic stress criterion and the plastic instability criterion. The deformation zone geometry criterion has also been used for comparison. The predictions fairly agree with the experimental results.

Buckle Propagation Analysis of Deep-Water Petroleum Transmission Pipelines with Axial Tension

2014 ◽  
Vol 1008-1009 ◽  
pp. 1134-1143 ◽  
Author(s):  
Sun Ting Yan ◽  
Yin Fa Zhu ◽  
Zhi Jiang Jin ◽  
Hao Ye
Keyword(s):  
Plastic Hinge ◽  
External Pressure ◽  
Isotropic Hardening ◽  
Rigid Plastic ◽  
Perfectly Plastic ◽  
Fitting Procedure ◽  
Plastic Materials ◽  
Buckle Propagation ◽  
Elastic Perfectly Plastic ◽  
Hinge Model

Quasi-static finite element simulation is carried out on buckle propagation phenomenon of offshore pipelines under external pressure. Arc-length method and volume-controlled static analysis by employing hydrostatic fluid element F3D4 are employed to calculate the steady buckle propagation pressure. After verifying the validity of numerical model, emphasis is on the influence of tension on propagation pressure considering isotropic hardening elastoplastic and elastic-perfectly plastic materials. Parametric study is conducted to include the effect of diameter-thickness ratio, after which two empirical equations are derived by curve fitting procedure. Finally, some comments on the results obtained through rigid-plastic hinge model are presented and a modified plastic hinge model including effect of material anisotropy is derived. The results can serve as a reference for more reasonable design of buckle arrestors.

Geometric Instabilities in Isotropic Plastic Solids Under Increasing Uniaxial Compression

1972 ◽  
Vol 39 (2) ◽  
pp. 431-437 ◽  
Author(s):  
J. B. Newman
Keyword(s):  
Shear Stress ◽  
Strain Hardening ◽  
Uniaxial Compression ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Rigid Plastic ◽  
Axisymmetric Mode ◽  
Plastic Materials ◽  
Compressive Flow ◽  
Shanley Theory

This analysis seeks three-dimensional instabilities of uniaxial compressive flow in isotropic, strain-hardening, rigid-plastic materials of the Mises and maximum shear stress types. No instabilities are found for Mises materials. Maximum shear materials display axisymmetric, “deflectional”, and “higher-order” buckling. For increasingly slender specimens, the deflectional buckling process merges into that of the Shanley theory. The axisymmetric mode raises the possibility that instabilities contribute to the double axial bulging of ductile compression specimens reported by Na´da´i.

Finite Twisting and Expansion of a Hole in a Rigid/Plastic Plate

1963 ◽  
Vol 30 (4) ◽  
pp. 605-612 ◽  
Author(s):  
R. P. Nordgren ◽  
P. M. Naghdi
Keyword(s):  
Plane Stress ◽  
Work Hardening ◽  
Infinite Plate ◽  
Yield Function ◽  
The State ◽  
Numerical Results ◽  
Plastic Plate ◽  
Rigid Plastic ◽  
Combined Action ◽  
Concentric Circles

This paper is concerned with the finite twisting and expansion of an annular rigid/plastic plate in the state of plane stress. The plate, bounded by two concentric circles one of which may extend to infinity, is subjected in its plane to the combined action of pressure on the inner boundary and a couple due to circumferential shear. A detailed solution which includes the effect of isotropic work hardening is obtained with the use of Tresca’s yield function and its associated flow rules and the corresponding solution with the use of Mises’ yield function and its associated flow rules is also discussed. Numerical results are given which illustrate the influence of twisting on the expansion of a hole in an infinite plate.

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