scholarly journals Thermoelastic investigation of residual stress: plastic deformation and the change in thermoelastic constant

2010 ◽  
Vol 6 ◽  
pp. 38016 ◽  
Author(s):  
A.F. Robinson ◽  
J.M. Dulieu-Barton ◽  
S. Quinn ◽  
R.L. Burguete
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Thermoelastic Constant

The Effect of Plastic Deformation on the Thermoelastic Constant and the Potential to Evaluate Residual Stress

2011 ◽  
Vol 70 ◽  
pp. 458-463 ◽  
Author(s):  
A. F. Robinson ◽  
Janice M. Dulieu-Barton ◽  
S. Quinn ◽  
R. L. Burguete
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Strain Hardening ◽  
Thermoelastic Stress ◽  
Paint Coating ◽  
Full Field ◽  
Thermoelastic Constant ◽  
Thermoelastic Response ◽  
Measured Change

In some metals it has been shown that the introduction of plastic deformation or strain modifies the thermoelastic constant, K. If it was possible to define the magnitude of the change in thermoelastic constant over a range of plastic strain, then the plastic strain that a material has experienced could be established based on a measured change in the thermoelastic constant. This variation of the thermoelastic constant and the ability to estimate the plastic strain that has been experienced, has potential to form the basis of a novel non-destructive, non-contact, full-field technique for residual stress assessment using thermoelastic stress analysis (TSA). Recent research has suggested that the change in thermoelastic constant is related to the material dislocation that occurs during strain hardening, and thus the change in K for a material that does not strain harden would be significantly less than for a material that does. In the work described in this paper, the change in thermoelastic constant for three materials (316L stainless steel, AA2024 and AA7085) with different strain hardening characteristics is investigated. As the change in thermoelastic response due to plastic strain is small, and metallic specimens require a paint coating for TSA, the effects of the paint coating and other test factors on the thermoelastic response have been considered.

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.

scholarly journals Elasto-plastic analysis of the contact region between a rigid ellipsoid and a semi-flat surface

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879739 ◽  
Author(s):  
Pengyang Li ◽  
Lingxia Zhou ◽  
Fangyuan Cui ◽  
Quandai Wang ◽  
Meiling Guo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Contact Pressure ◽  
Contact Region ◽  
Three Dimensional ◽  
Von Mises Stress ◽  
Effective Plastic Strain ◽  
Normal Forces ◽  
Von Mises

When the load acting on a mechanical structure is greater than the yield strength of the material, the contact surface will undergo plastic deformation. Cumulative plastic deformation has an important influence on the lifespan of mechanical parts. This article presents a three-dimensional semi-analytical model based on the conjugate gradient method and fast Fourier transform algorithm, with the aim of studying the characteristic parameters of the contact region between a rigid ellipsoid and elasto-plastic half-space. Moreover, normal forces and tangential traction were considered, as well as the contact pressure resulting from various sliding speeds and friction coefficients. The contact pressure, effective plastic strain, von Mises stress, and residual stress were measured and shown to increase with increasing sliding velocity. Finally, when the friction coefficient, contact pressure, and effective plastic strain are increased, the von Mises stress is also shown to increase, whereas the residual stress decreases.

scholarly journals Achievements in Micromagnetic Techniques of Steel Plastic Stage Evaluation

2020 ◽  
Vol 20 (1) ◽  
pp. 16-55 ◽  
Author(s):  
M. F. de Campos
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Elastic Deformation ◽  
Magnetic Measurements ◽  
Soft Magnetic Materials ◽  
Hysteresis Curve ◽  
Hole Drilling ◽  
Hole Drilling Method ◽  
Drilling Method ◽  
The Difference

AbstractThe investigation of plastic deformation and residual stress by non-destructive methods is a subject of large relevance for the industry. In this article, the difference between plastic and elastic deformation is discussed, as well as their effects on magnetic measurements, as hysteresis curve and Magnetic Barkhausen Noise. The residual stress data can be obtained with magnetic measurements and also by the hole drilling method and x-ray diffraction measurements. The residual stress level obtained by these three different methods is different, because these three techniques evaluate the sample in different depths. Effects of crystallographic texture on residual stress are also discussed. The magnetoelastic term should be included in micromagnetic methods for residual stress evaluation. It is discussed how the micromagnetic energy Hamiltonian should be expressed in order to evaluate elastic deformation. Plastic deformation can be accounted in micromagnetic models as a term that increases the coercive field in soft magnetic materials as the steels are.

Analysis of Leveling Strategy for a Plate Mill

2010 ◽  
Vol 145 ◽  
pp. 424-428 ◽  
Author(s):  
Li Cui ◽  
Xian Lei Hu ◽  
Xiang Hua Liu
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Time Delay ◽  
Static Pressure ◽  
High Strength ◽  
Plate Mill ◽  
Elastic Plastic ◽  
Residual Curvature ◽  
Deformation Ratio

In order to analysis the effect of leveling strategy on the quality of plate products, the curvature integration by elastic-plastic differences was adopted to simulate leveling results by different leveling strategy. It had studied plastic deformation ratio, residual stress, residual curvature and leveling force for different leveling strategies to find the effectual strategy and the adaptability conditions were given. Additionally, static pressure leveling with the time delay strategy was analyzed, which was proved to be an effectual strategy to resolve the leveling problem for high strength thicker plate by a certain 3500mm mill plate.

Determination of X-ray Elastic Constants in a Ti-14Al-21Nb Nb Alloy and a Ti-14Al-21Nb/SiC Metal Matrix Composite

1990 ◽  
Vol 34 ◽  
pp. 689-698 ◽  
Author(s):  
J. Jo ◽  
R. W. Hendricks ◽  
W. D. Brewer ◽  
Karen M. Brown
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Elastic Constant ◽  
Theoretical Calculation ◽  
Metal Matrix Composite ◽  
Elastic Constants ◽  
Metal Matrix ◽  
Intrinsic Value ◽  
X Ray

Residual stress values in a material are governed by the measurements of the atomic spacings in a specific crystallographic plane and the elastic constant for that plane. It has been reported that the value of the elastic constant depends on microstructure, preferred orientation, plastic deformation and morphology [1], Thus, the theoretical calculation of the elastic constant may deviate from the intrinsic value for a real alloy.

scholarly journals Plastic Deformation and Residual Stress in High Speed Turning of AD730™ Nickel-based Superalloy with PCBN and WC Tools

Procedia CIRP ◽  
2018 ◽  
Vol 71 ◽  
pp. 440-445 ◽  
Author(s):  
Z Chen ◽  
J.M. Zhou ◽  
R.L. Peng ◽  
R M’Saoubi ◽  
D Gustafsson ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
High Speed ◽  
High Speed Turning ◽  
Nickel Based Superalloy

Evaluation of Tensile Properties and Bending-Induced Residual Stress of Slender Copper Pipe

2006 ◽  
Vol 321-323 ◽  
pp. 636-639
Author(s):  
Sang Young Kim ◽  
Hyung Ick Kim ◽  
Chang Sung Seok ◽  
Jae Kwan Lee ◽  
Jin Yong Mo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Yield Strength ◽  
Tensile Properties ◽  
Raw Material ◽  
Copper Pipe ◽  
Bending Process ◽  
Complex Manner

Used pipes in various mechanisms and structures are produced from raw material by extruding and drawing. The properties such as yield strength, tensile strength, and elongation of a pipe produced by these methods are different from the properties of their raw material. But designers use the properties of the raw material because the actual properties of the pipes are difficult to obtain from testing. Also, the pipe is used after it has been bent in a complex manner and cut to fit it to mechanisms and structures. The bending process, especially, induces deformation of the pipe’s section and residual stress, which are involved in the plastic deformation of the bended pipes. This residual stress affects the pipe’s properties, including its fatigue life. Therefore, it is very important to understand the residual stress of a material. But, the distribution of residual stress of a U-shaped pipe, which is examined in this study, is very complicated and cannot be measured exactly.

Surface Layers' Real Structure of Metals Exposed to Inhomogeneous Thermal Fields and Plastic Deformation

2010 ◽  
Vol 163 ◽  
pp. 59-63 ◽  
Author(s):  
Zdenek Pala ◽  
N. Ganev ◽  
Jan Drahokoupil ◽  
Alexej Sveshnikov
Keyword(s):  
Residual Stress ◽  
Plastic Deformation ◽  
Grain Size ◽  
Surface Layer ◽  
Real Structure ◽  
End Mill ◽  
Surface Layers ◽  
Thermal Fields ◽  
Mill Speed

Inhomogeneous thermal fields and plastic deformation are two basic phenomena present during surface creation and substantially determine future real structure of the surface layers. In the following, a closer look will be taken at some aspects connected with real structure of milled and ground steels. Impact of end-mill speed and thickness of removed layer on grain size, macroscopic and microscopic residual stress is discussed. Possibility of prestrained surface layer in ground steel has been examined on a set of five types of steels.

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