A STUDY OF RESIDUAL STRESS FORMATION AFTER ELASTOPLASTIC DEFORMATION OF PIPE WALLS, MADE FROM DISPERSE-HARDENED ALUMINUM ALLOY, AS A RESULT OF EXTERNAL PRESSURE

2021 ◽  
pp. 102-117
Author(s):  
O.V. Matvienko ◽  
◽  
O.I. Daneyko ◽  
T.A. Kovalevskaya ◽  
◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Residual Stresses ◽  
Applied Pressure ◽  
External Pressure ◽  
Deformable Solid ◽  
First Approximation ◽  
Large Particles ◽  
Order Of Magnitude ◽  
Stress Formation ◽  
Combination Of Methods

The formation of residual stresses after elastic-plastic deformation of pipe walls as a result of external pressure is studied using the approach based on a combination of methods of the physical theory of plasticity and mechanics of a deformable solid. As a result of the research, it is found that at the same value of the applied pressure, the thickness of the area subjected to plastic deformation is less for the alloys reinforced with large particles than for those reinforced with small particles. The values of the circumferential and axial residual stresses exceed the value of the radial residual stresses by more than an order of magnitude. Therefore, in the first approximation, the radial residual stresses can be neglected.

scholarly journals Transient dynamics of an elastic Hele-Shaw cell due to external forces with application to impact mitigation

2016 ◽  
Vol 800 ◽  
pp. 517-530 ◽  
Author(s):  
A. Tulchinsky ◽  
A. D. Gat
Keyword(s):  
Elastic Plate ◽  
Plate Theory ◽  
Applied Pressure ◽  
Elastic Interaction ◽  
External Pressure ◽  
Transient Dynamics ◽  
Impact Mitigation ◽  
Order Of Magnitude ◽  
External Forces ◽  
Hele Shaw Cell

We study the transient dynamics of a viscous liquid contained in a narrow gap between a rigid surface and a parallel elastic plate. The elastic plate is deformed due to an externally applied time-varying pressure field. We model the flow field via the lubrication approximation and the plate deformation by the Kirchhoff–Love plate theory. We obtain a self-similarity solution for the case of an external point force acting on the elastic plate. The pressure and deformation field during and after the application of the external force are derived and presented by closed-form expressions. We examine a distributed external pressure, spatially uniform and linearly increasing with time, acting on the elastic plate over a finite region and during a finite time period, similar to the viscous–elastic interaction time-scale. The interaction between elasticity and viscosity is shown to reduce by an order of magnitude the pressure within the Hele-Shaw cell compared with the externally applied pressure. The results thus suggest that elastic Hele-Shaw configurations may be used to achieve significant impact mitigation.

scholarly journals Mathematical modeling of plastic deformation of a tube from dispersion-hardened aluminum alloy

2018 ◽  
Vol 243 ◽  
pp. 00008 ◽  
Author(s):  
Oleg Matvienko ◽  
Olga Daneyko ◽  
Tatyana Kovalevskaya
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Plastic Deformation ◽  
External Pressure ◽  
Dislocation Loops ◽  
Balance Equations ◽  
Deformable Solid ◽  
Deformation Defects ◽  
Resistance Decrease ◽  
The Mathematical Model

The influence of the internal and external pressure subjected to the tube from dispersion-hardened aluminium alloy was investigated. The approach which combines methods of crystal plasticity and mechanics of deformable solid was used to explore the limits of elastic and plastic resistance. The mathematical model of plastic deformation includes balance equations for deformation defects with regard to the generation and annihilation of shear dislocations, vacancy and interstitial prismatic dislocation loops, and dislocations in dipole configurations of vacancy and interstitial types and also equilibrium equation, geometrical and physical relations between the deformations, displacements and stresses. It has been established that as the temperature increases, the limits of the elastic and plastic resistance decrease. Results of investigation demonstrate that the hardening the alloy by nanoparticles significantly improves the strength characteristics of the material.

scholarly journals The Influence of Thermomechanical Coupling on the Behaviour of Athick-Walled Metallic Tube Subjected to Internal Pressure

2018 ◽  
Vol 23 (3) ◽  
pp. 751-766
Author(s):  
Z. Śloderbach
Keyword(s):  
Plastic Deformation ◽  
Heat Flow ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Coupling Effect ◽  
Applied Pressure ◽  
Thermomechanical Coupling ◽  
Stored Energy ◽  
Adiabatic Processes ◽  
Elastic Unloading

Abstract In this study, the influence of thermomechanical coupling effect - the effect of thermal expansion due to dissipation of the energy of plastic deformation, with and without taking into account the stored energy of plastic deformation (SEPD) for the distribution of stresses, strains, temperature, the applied pressure and the residual stresses is examined. The residual stresses remain in a thick-walled tube (a cylindrical thick-walled tank) after removing the internal pressure in the process of purely elastic unloading. The analysis is made on the example of an analitycal solution for a thick-walled tube subjected to a quasistatically increasing internal pressure for the case of adiabatic processes (without heat flow). Since the loading with internal pressure is quasi-static (monotonic), then neglecting the process of heat flow can lead to some different results in calculated stresses, deformations, temperature, internal pressure and residual stresses. The calculations for isothermal type of processes of deformations (without heat or ideal cooling) are also performed for the estimation of these differences. The results calculated for the process with heat flow should be intermediate between the values obtained for isothermal and adiabatic processes.

Quantum Chemistry Simulation of 60-Fullerene Interaction under External Pressure

2005 ◽  
Vol 60 (1-2) ◽  
pp. 41-46 ◽  
Author(s):  
Alexey V. Khavryutchenko ◽  
Vladimir D. Khavryutchenko
Keyword(s):  
Quantum Chemical ◽  
Chemical Method ◽  
Applied Pressure ◽  
Heat Of Formation ◽  
External Pressure ◽  
Space Structures ◽  
Order Of Magnitude ◽  
Fullerene Dimers ◽  
Semi Empirical ◽  
Quantum Chemistry Simulation

The results of the interaction of two 60-fullerene molecules interaction under external pressure, studied by a semi-empirical PM3 quantum chemical method, are reported. A set of 15 space structures of 60-fullerene dimers from the simplest one up to partially graphitized material has been simulated. Calculated pressures referring to the dimers’ formation reproduce the experimental order of magnitude rather well. The dependences of the heat of formation and the force ballancing the applied pressure versus compression have been determined. A mechanism of the dimerization is proposed.

GRAIN REFINEMENT AND MICROSTRUCTURE EVOLUTION IN ALUMINUM A2618 ALLOY BY HIGH-PRESSURE TORSION

2016 ◽  
Vol 78 (6-9) ◽  
Author(s):  
Intan Fadhlina Mohamed ◽  
Seungwon Lee ◽  
Kaveh Edalati ◽  
Zenji Horita ◽  
Shahrum Abdullah ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Grain Refinement ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Saturation Level ◽  
Microstructural Refinement ◽  
Average Grain Size

This work presents a study related to the grain refinement of an aluminum A2618 alloy achieved by High-Pressure Torsion (HPT) known as a process of Severe Plastic Deformation (SPD). The HPT is conducted on disks of the alloy under an applied pressure of 6 GPa for 1 and 5 turns with a rotation speed of 1 rpm at room temperature. The HPT processing leads to microstructural refinement with an average grain size of ~250 nm at a saturation level after 5 turns. Gradual increases in hardness are observed from the beginning of straining up to a saturation level. This study thus suggests that hardening due to grain refinement is attained by the HPT processing of the A2618 alloy at room temperature.

Effect of Residual Stress or Plastic Deformation History on Fatigue Life Simulation of Pipeline Dents

2018 ◽  
Author(s):  
Xian-Kui Zhu ◽  
Rick Wang
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Strain History ◽  
Deformation History ◽  
Stress Strain ◽  
Element Analysis ◽  
Fea Model

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.

Mathematical Model Establishment and Analysis on the Pipe Deformation under External Pressure with the Ovality

2013 ◽  
Vol 760-762 ◽  
pp. 2263-2266
Author(s):  
Kang Yong ◽  
Wei Chen
Keyword(s):  
Mathematical Model ◽  
Theoretical Analysis ◽  
Yield Strength ◽  
Residual Stresses ◽  
Numerical Simulations ◽  
Significant Influence ◽  
External Pressure ◽  
Pipe Diameter ◽  
Axial Loads ◽  
The Stability

Beside the residual stresses and axial loads, other factors of pipe like ovality, moment could also bring a significant influence on pipe deformation under external pressure. The Standard of API-5C3 has discussed the influences of deformation caused by yield strength of pipe, pipe diameter and pipe thickness, but the factor of ovality degree is not included. Experiments and numerical simulations show that with the increasing of pipe ovality degree, the anti-deformation capability under external pressure will become lower, and ovality affecting the stability of pipe shape under external pressure is significant. So it could be a path to find out the mechanics relationship between ovality and pipe deformation under external pressure by the methods of numerical simulations and theoretical analysis.

The Effect of Several Finishing Processes on the Fatigue Resistance of Hole Surfaces

1989 ◽  
Vol 111 (1) ◽  
pp. 71-73 ◽  
Author(s):  
M. O. Lai ◽  
A. Y. C. Nee
Keyword(s):  
Surface Roughness ◽  
Plastic Deformation ◽  
Fatigue Life ◽  
Residual Stresses ◽  
Fatigue Resistance ◽  
Radial Direction ◽  
Fatigue Loading ◽  
Steel Plates ◽  
Finishing Processes ◽  
Compressive Residual Stresses

This investigation examines the effects of different finishing processes on the fatigue life of premachined holes in Assab 760 steel plates. The finishing processes studied were reaming, ballizing, and emery polishing. A general decrease in fatigue life with increase in surface roughness is observed for all the processes employed. In comparing the different processes, for a constant surface roughness, polishing is generally found to give the longest fatigue life while ballizing, in spite of the greater compressive residual stresses induced on the surface of the finished hole, the shortest. The surprising phenomenon was found to be attributed to the amount of plastic deformation occurred before fatigue loading. For Assab 760 steel, a prestrain in the radial direction of less than about 2.5 percent appeared to reduce the fatigue resistance of the material.

scholarly journals Residual Stresses and Plastic Deformation in Self-Pierce Riveting of Dissimilar Aluminum-to-Magnesium Alloys

2018 ◽  
Vol 11 (2) ◽  
pp. 139-150 ◽  
Author(s):  
J.F.C. Moraes ◽  
Xuming Su ◽  
Luke N. Brewer ◽  
Brian J. Fay ◽  
J.R. Bunn ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Residual Stresses ◽  
Magnesium Alloys

Chemo-mechanical Model of Lithium Dendrite Growth Impacted By External Pressure and Plastic Deformation

2021 ◽  
Vol MA2021-02 (3) ◽  
pp. 360-360
Author(s):  
Julia Meyer ◽  
Partha P. Mukherjee ◽  
Scott A. Roberts ◽  
Katharine Harrison
Keyword(s):  
Plastic Deformation ◽  
Mechanical Model ◽  
External Pressure ◽  
Dendrite Growth ◽  
Lithium Dendrite
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