Characterization of Strain Hardening Behavior and Residual Stress Induction Used For Crack Arrest in a Biocompatible Material

2009 ◽  
Vol 1242 ◽  
Author(s):  
G. Urriolagoitia-Sosa ◽  
A. Molina-Ballinas ◽  
G. Urriolagoitia-Calderón ◽  
L. H. Hernández-Gómez ◽  
y J. M. Sandoval-Pineda
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stress Field ◽  
Strain Hardening ◽  
Structural Integrity ◽  
Crack Arrest ◽  
Mechanical Resistance ◽  
Residual Stress Field ◽  
Strain Hardening Behavior

ABSTRACTFor centuries, the manipulation of mechanical properties for the development of components has been extremely important. Its relevance is based on improving the service life in the components. The aim of some techniques that have been used is to introduce strain hardening (tensile) and a beneficial residual stress field. Nevertheless, the application of both methods is very common when the component is manufactured, but the lack of knowledge of the final physical state of the material could compromise the structural integrity of the final product. This work presents a numerical evaluation concerning the characterization of a stainless steel AISI 316L, having a homogeneous axial history and a residual stress field. The relevance of the work is focused in a new methodology that can be used to improve the mechanical resistance of the component and to arrest crack propagation. By altering the mechanical properties of the material, it could be possible to delay nucleation and interrupt the propagation of cracks. This study also shows that if the strain hardening behaviour and the introduction of the residual stress field is not done properly, it could result in a component susceptible to fail. In the same sense, bending tests are proposed to provide tensile and compressive stress profiles.

scholarly journals Numerical and Experimental Analysis in the Manipulation of the Mechanical Properties for Enhancing the Mechanical Resistance of a Material

2011 ◽  
Vol 9 (02) ◽  
Author(s):  
G. Urriolagoitia-Sosa ◽  
A. Molina-Ballinas ◽  
G. Urriolagoitia-Calderón ◽  
L. H. Hernández-Gómez ◽  
B. Romero-Ángeles ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stress Field ◽  
Previous History ◽  
The State ◽  
Mechanical Resistance ◽  
Residual Stress Field ◽  
Bending Tests ◽  
Evolution And Development ◽  
Stress Profiles

The evolution and development of mankind has been partly possible thanks to the transformation of diverse types ofmaterials and the manipulation of their mechanical properties. This work is focused on numerical and experimentalevaluations of the improvement of the mechanical resistance of one material (AISI 316L) through the application ofstrain hardening and a residual stress field induction. Additionally, the state of the stresses in the component isdetermined by the application of the Crack Compliance Method, a destructive method based on the FractureMechanics Theory. The relevance of the work lies on the implementation of a new methodology which can be used toimprove the mechanical resistance of the component by altering the state of the mechanical properties of thismaterial. This research also demonstrates that strain hardening and induction of a residual stress field must beperformed carefully or it could result in a component susceptible to failure. In this respect, bending tests are proposedto provide tensile and compressive stress profiles and to corroborate previous history loading on the material

Characterisation of the Residual Stress Field and Mechanical Properties of a Narrow-Gap Girth-Welded Stainless Steel Pipe and Subsequent Application to a Numerical Model

2011 ◽  
Author(s):  
Robert J. A. McCluskey ◽  
Andrew H. Sherry ◽  
Martin R. Goldthorpe
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Stress Field ◽  
Steel Pipe ◽  
Primary Circuit ◽  
Narrow Gap ◽  
Residual Stress Field ◽  
Butt Weld ◽  
Stainless Steel Pipe

Girth-butt welds are used to join sections of stainless steel pipe in the primary circuit of Pressurised Water Reactors. The welding process creates residual stress fields across the weldment, which can contribute to the crack driving force when a defect is present. Assessment procedures account for such defects, enabling safety justifications to be made for continued operation of nuclear power plant. Such procedures require the size and nature of the residual stress field to be determined in order to make reliable structural integrity assessments. This paper describes the investigation of the residual stress field and fracture behaviour of a recently developed narrow-gap 304-stainless steel girth-butt weld in a primary circuit pipe. Two residual stress measurement techniques, Neutron Diffraction (ND) and incremental Deep Hole Drilling (iDHD), were used to measure the original residual stress field in the pipe weld. A second pipe weld specimen was used to fabricate tensile and fracture toughness specimens from which the mechanical properties of the weld material were determined. The residual stress and mechanical test data were used to develop numerical models of the pipe weld containing a postulated circumferential defect under an applied axial load. The numerical simulation results were applied within a failure assessment diagram, comparing different interaction parameters on the prediction of component failure load.

An Energy-Based Residual Stress Field Reconstruction Approach Using Limited Measurements

2015 ◽  
Author(s):  
H.-B. Liu ◽  
Y.-P. Li ◽  
Y.-Q. Wang ◽  
X.-J. Sheng
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Stress Field ◽  
Structural Integrity ◽  
Spline Interpolation ◽  
Residual Stress Field ◽  
Strain Compatibility ◽  
Integrity Assessment ◽  
Field Reconstruction ◽  
Initial Stress Field

To characterize the residual stress distribution is very crucial for workpiece fatigue lifetime and structural integrity assessment. An energy-based residual stress field reconstruction approach using limited measurements is proposed. Firstly, the Ferguson spline interpolation technique is employed as the stress interpolation base of the 2-order stress tensor. Then, an initial stress field can be reconstructed using the overall boundary conditions by minimizing strain energy. Further, the stress distribution is modified according to strain compatibility equation. At last, a typical stress unit from the artificial stress field constructed by FEM, was picked up as an input set to verify the validation of the developed model and algorithm numerically. It was demonstrated that the energy-based scheme was efficient and reliable to reconstruct the residual stress field from limited measurements.

A Comparison of 2D and 3D Fracture Assessments in the Presence of Residual Stresses

2007 ◽  
Author(s):  
Simon J. Lewis ◽  
Christopher E. Truman ◽  
David J. Smith
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Structural Integrity ◽  
Three Dimensional ◽  
External Loading ◽  
Assessment Procedure ◽  
J Integral ◽  
Residual Stress Field ◽  
Fracture Parameters ◽  
Three Dimensional Simulations

This paper presents an investigation into the effects of an initial residual stress field on fracture parameters, calculated via an energy-type integral method, in two and three-dimensional simulations. A residual stress field was introduced into a modified single edge notched bend, SEN(B), specimen using an in-plane compression procedure, such that a crack introduced into the specimen experienced opening displacement, even in the absence of external loading. J integral calculation was undertaken using standard two-dimensional area formulations and pointwise three-dimensional formulations, as well as using modified two- and three-dimensional routines developed to provide path independence in the presence of initial strain fields and non-monotonic plastic loading. The paper will describe the application of these modified J-integral techniques and use the results to re-interpret experimental fracture test data obtained from a set of A533B ferritic steel SEN(B) specimens. The implications for structural integrity assessments in the presence of residual stress fields, as well as the calculation route chosen for determination of fracture parameters, were explored in the context of the R6 assessment procedure. In particular, the different levels of conservatism in the assessments resulting from two- and three-dimensional simulations will be highlighted.

scholarly journals Influence of Residual Stress on Fatigue Design of AISI 304 Stainless Steel

2011 ◽  
Vol 7 (2) ◽  
pp. 44 ◽  
Author(s):  
L. Singh ◽  
R.A. Khan ◽  
M.L. Aggarwal
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Stainless Steel ◽  
Fatigue Strength ◽  
Stress Field ◽  
Shot Peening ◽  
Compressive Residual Stress ◽  
Residual Stress Field ◽  
Aisi 304 ◽  
Fatigue Design

 Austenitic stainless steel cannot be hardened by any form of heat treatment, in fact, quenching from 10000C merely softens them. They are usually cold worked to increase the hardness. Shot peening is a cold working process that changes micro-structure as well as residual stress in the surface layer. In the present work, the compressive residual stress and fatigue strength of AISI 304 austenitic stainless steel have been evaluated at various shot peening conditions. The improvement in various mechanical properties such as hardness, damping factors and fatigue strength was noticed. Compressive residual stress induced by shot peening varies with cyclic loading due to relaxation of compressive residual stress field. The consideration of relaxed compressive residual stress field instead of original compressive residual stress field provides reliable fatigue design of components. In this paper, the exact reductions in weight and control of mechanical properties due to shot peening process are discussed. 

Nondestructive testing and characterization of residual stress field using an ultrasonic method

2015 ◽  
Vol 29 (2) ◽  
pp. 365-371 ◽  
Author(s):  
Wentao Song ◽  
Chunguang Xu ◽  
Qinxue Pan ◽  
Jianfeng Song
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Nondestructive Testing ◽  
Ultrasonic Method ◽  
Residual Stress Field

Elastoplastic Analysis of the Residual Stress in Chain Links

2002 ◽  
Author(s):  
Pedro M. Calas Lopes Pacheco ◽  
Paulo Pedro Kenedi ◽  
Jorge Carlos Ferreria Jorge
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stress Field ◽  
Residual Stresses ◽  
Structural Integrity ◽  
Economic Losses ◽  
Mooring Line ◽  
Residual Stress Field ◽  
Traditional Design ◽  
Chain Links

Mooring lines of offshore oil exploitation platforms consist of long lengths of steel chain links, wire ropes and other accessories. Usually, these lines are designed for an operational life of about 20 years and periodic inspections are mandatory for monitoring the structural integrity of these components. The failure of a single element in a mooring line can cause incalculable environmental damage and severe economic losses. The ocean adverse environment loading produced by the combination of the wind, waves and currents leads to a complex alternate loading that can promote fatigue and crack propagation. Residual stress plays a preponderant part in the structural integrity of a mechanical component subjected to such loading. Offshore mooring line components as chain links enter in operation with a residual stress field created by the proof test dictated by offshore standards. However, the traditional design of such mechanical components does not consider the presence of residual stress. This study concerns about predict the residual stress field present in stud and studless chain links prior to operation to compare the fatigue life predicted by the traditional design methodology with the one predicted considering the residual stresses states present before operation. Numeric simulations with an elastoplastic finite element model are used to estimate the residual stress along the chain link that are present after the proof test and before operation. The results indicate that the presence of residual stresses modify significantly the fatigue life of the component.

scholarly journals Residual stress in geometric features subjected to laser shock peening

2014 ◽  
Vol 229 (11) ◽  
pp. 1923-1938 ◽  
Author(s):  
M Achintha ◽  
D Nowell
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Structural Integrity ◽  
Laser Shock Peening ◽  
Geometric Features ◽  
Laser Shock ◽  
Computationally Efficient ◽  
Residual Stress Field ◽  
Subsequent Performance ◽  
Shock Peening

This article reports selected findings from a collaborative research study into the fundamental understanding of laser shock peening (LSP), when applied to key airframe and aero-engine alloys. The analyses developed include explicit simulations of the peening process together with a simpler eigenstrain approach, which may be used to provide an approximation to the residual stress field in a number of geometries. These are chosen to represent parts of structural components under conditions relevant to service applications. The article shows that the eigenstrain approach can provide good approximations to the stress field in most circumstances and may provide a computationally efficient tool for exploring different peening strategies. Both explicit and eigenstrain results demonstrate that the interaction between the LSP process and geometric features is important for understanding the subsequent performance of components. Particularly relevant for engineering applications is that not all instances of LSP application may provide an improvement in structural integrity.

scholarly journals Characterization of Mechanical Heterogeneity in Dissimilar Metal Welded Joints

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4145
Author(s):  
He Xue ◽  
Zheng Wang ◽  
Shuai Wang ◽  
Jinxuan He ◽  
Hongliang Yang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Welded Joints ◽  
Structural Integrity ◽  
Material Interfaces ◽  
Mechanical Heterogeneity ◽  
Finite Element Software ◽  
Dissimilar Metal ◽  
Stress Changes

Dissimilar metal welded joints (DMWJs) possess significant localized mechanical heterogeneity. Using finite element software ABAQUS with the User-defined Material (UMAT) subroutine, this study proposed a constitutive equation that may be used to express the heterogeneous mechanical properties of the heat-affected and fusion zones at the interfaces in DMWJs. By eliminating sudden stress changes at the material interfaces, the proposed approach provides a more realistic and accurate characterization of the mechanical heterogeneity in the local regions of DMWJs than existing methods. As such, the proposed approach enables the structural integrity of DMWJs to be analyzed in greater detail.

scholarly journals Residual stresses in thermite welded rails: significance of additional forging

2020 ◽  
Vol 64 (7) ◽  
pp. 1195-1212
Author(s):  
B. Lennart Josefson ◽  
R. Bisschop ◽  
M. Messaadi ◽  
J. Hantusch
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Residual Stresses ◽  
Weld Metal ◽  
Welding Process ◽  
Surface Zone ◽  
Fe Model ◽  
Uneven Surface ◽  
Residual Stress Field ◽  
High Dynamic

Abstract The aluminothermic welding (ATW) process is the most commonly used welding process for welding rails (track) in the field. The large amount of weld metal added in the ATW process may result in a wide uneven surface zone on the rail head, which may, in rare cases, lead to irregularities in wear and plastic deformation due to high dynamic wheel-rail forces as wheels pass. The present paper studies the introduction of additional forging to the ATW process, intended to reduce the width of the zone affected by the heat input, while not creating a more detrimental residual stress field. Simulations using a novel thermo-mechanical FE model of the ATW process show that addition of a forging pressure leads to a somewhat smaller width of the zone affected by heat. This is also found in a metallurgical examination, showing that this zone (weld metal and heat-affected zone) is fully pearlitic. Only marginal differences are found in the residual stress field when additional forging is applied. In both cases, large tensile residual stresses are found in the rail web at the weld. Additional forging may increase the risk of hot cracking due to an increase in plastic strains within the welded area.

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