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Showing papers on "Residual stress published in 2001"


Journal ArticleDOI
TL;DR: In this paper, the effect of residual stresses on fatigue lifetimes and structural integrity are first summarised, followed by the definition and measurement of residual stress, which are characterised according to the characteristic length scale over which they self-equilibrate.
Abstract: Residual stress is that which remains in a body that is stationary and at equilibrium with its surroundings. It can be very detrimental to the performance of a material or the life of a component. Alternatively, beneficial residual stresses can be introduced deliberately. Residual stresses are more difficult to predict than the in-service stresses on which they superimpose. For this reason, it is important to have reliable methods for the measurement of these stresses and to understand the level of information they can provide. In this paper, which is the first part of a two part overview, the effect of residual stresses on fatigue lifetimes and structural integrity are first summarised, followed by the definition and measurement of residual stresses. Different types of stress are characterised according to the characteristic length scale over which they self-equilibrate. By comparing this length to the gauge volume of each technique, the capability of a range of techniques is assessed. In the sec...

1,317 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examine the nature and origins of residual stresses across a range of scales, from the long range residual stress fields in engineering components and welded structures, through the interphase stresses present in composites and coatings, to the microscale interactions of phase transformations with local stresses.
Abstract: Residual stress is that which remains in a body that is stationary and at equilibrium with its surroundings. It can be detrimental when it reduces the tolerance of the material to an externally applied force, as is the case with welded joints. On the other hand, it can be exploited to design materials or components which are resistant to damage, toughened glass being a good example. This paper, the second part of a two part overview, the first part having been devoted to measurement techniques, examines the nature and origins of residual stresses across a range of scales. This extends from the long range residual stress fields in engineering components and welded structures, through the interphase stresses present in composites and coatings, to the microscale interactions of phase transformations with local stresses.

773 citations


Book
01 Aug 2001
TL;DR: In this article, the authors present practical information and data to help minimize and control the effects of residual stresses and distortion, including recommended heat treating practices, methods for maintaining temperature uniformity during heating, tips for preventing oxide formation, and techniques for measuring residual stresses.
Abstract: Distortion, cracking, and residual stresses are among the most important concerns for heat treaters, manufacturing engineers, and design engineers. This work includes practical information and data to help minimize and control the effects of residual stresses and distortion. Topics covered include recommended heat treating practices, methods for maintaining temperature uniformity during heating, tips for preventing oxide formation, and techniques for measuring residual stresses, to name but a few. Designed as both a practical and theoretical reference, this book features contributions from recognized experts from around the world. Much of this data has been unavailable in the United States until now. Contents: Introduction to residual stress formation and distortion; Effects of materials and processing on residual stress formation; Design considerations, and much more.

591 citations


Journal ArticleDOI
TL;DR: In this paper, a part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses.
Abstract: A powerful new method for residual stress measurement is presented. A part is cut in two, and the contour, or profile, of the resulting new surface is measured to determine the displacements caused by release of the residual stresses. Analytically, for example using a finite element model, the opposite of the measured contour is applied to the surface as a displacement boundary condition. By Bueckner's superposition principle, this calculation gives the original residual stresses normal to the plane of the cut. This contour method is more powerful than other relaxation methods because it can determine an arbitrary cross-sectional area map of residual stress, yet more simple because the stresses can be determined directly from the data without a tedious inversion technique. The new method is verified with a numerical simulation, then experimentally validated on a steel beam with a known residual stress profile.

565 citations


Journal ArticleDOI
TL;DR: In this paper, a non-destructive method for measuring residual stresses in structural engineering components is described. But the method is not suitable for the analysis of the residual stress distributions introduced by welding and the beneficial stresses produced by autofrettage, cold hole expansion and shot peening.

385 citations


Journal ArticleDOI
F. Abe1, Kozo Osakada1, Masanori Shiomi1, K. Uematsu1, M. Matsumoto1 
TL;DR: In this article, a dual laser scanning system in which YAG and CO 2 laser beams are offset a small amount from each other and scanned is proposed to solve the problems of deflection and cracking caused by rapid heating and quenching.

357 citations


Journal ArticleDOI
TL;DR: In this article, an analytical model is proposed for estimation of residual stress relaxation, considering the magnitude and distribution of the residual stress, the degree of cold working required, the applied alternating and mean stresses, and the number of applied loading cycles.

338 citations


Journal ArticleDOI
TL;DR: In this article, real-time measurements of stress evolution during the deposition of Volmer-Weber thin films reveal a complex interplay between mechanisms for stress generation and stress relaxation.
Abstract: Real-time measurements of stress evolution during the deposition of Volmer–Weber thin films reveal a complex interplay between mechanisms for stress generation and stress relaxation. We observed a generic stress evolution from compressive to tensile, then back to compressive stress as the film thickened, in amorphous and polycrystalline Ge and Si, as well as in polycrystalline Ag, Al, and Ti. Direct measurements of stress relaxation during growth interrupts demonstrate that the generic behavior occurs even in the absence of stress relaxation. When relaxation did occur, the mechanism depended sensitively on whether the film was continuous or discontinuous, on the process conditions, and on the film/substrate interfacial strength. For Ag films, interfacial shear dominated the early relaxation behavior, whereas this mechanism was negligible in Al films due to the much stronger bonding at the Al/SiO2 interface. For amorphous Ge, selective relaxation of tensile stress was observed only at elevated temperatures...

318 citations


Journal ArticleDOI
Bodo Fiedler1, Masaki Hojo1, Shojiro Ochiai1, Karl Schulte, M Ando 
TL;DR: In this article, the parabolic Mohr failure criterion was applied to experimental results under different loading conditions and the results of the mechanical tests and a fractographic study of the fracture surfaces were correlated with the stress-state-dependent strength and fracture stress of the epoxy resin.

314 citations


Journal ArticleDOI
TL;DR: Comparing computed opening angles with published experimental data for the bovine carotid artery suggests that the material properties change continuously across the vessel wall and that stress, not strain, correlates well with growth in arteries.
Abstract: A simple phenomenological model is used to study interrelations between material properties, growth-induced residual stresses, and opening angles in arteries The artery is assumed to be a thick-walled tube composed of an orthotropic pseudoelastic material In addition, the normal mature vessel is assumed to have uniform circumferential wall stress, which is achieved here via a mechanical growth law Residual stresses are computed for three configurations: the unloaded intact artery, the artery after a single transmural cut, and the inner and outer rings of the artery created by combined radial and circumferential cuts The results show that the magnitudes of the opening angles depend strongly on the heterogeneity of the material properties of the vessel wall and that multiple radial and circumferential cuts may be needed to relieve all residual stress In addition, comparing computed opening angles with published experimental data for the bovine carotid artery suggests that the material properties change continuously across the vessel wall and that stress, not strain, correlates well with growth in arteries

303 citations


Journal ArticleDOI
TL;DR: In this paper, a finite element to predict the residual stresses induced by shot peening in a metal part and to relate these stresses to Almen intensity is proposed; the aim is to provide the designer with a useful tool with which to choose the optimal treatment parameters with respect to the mechanical behaviour of the peened parts.

Journal ArticleDOI
TL;DR: In this article, a new experimental technique is presented for making measurements of biaxial residual stress using load and depth sensing indentation (nanoindentation), which is based on spherical indentation and can be much more sensitive to residual stress than indentation with sharp pyramidal indenters like the Berkovich.
Abstract: A new experimental technique is presented for making measurements of biaxial residual stress using load and depth sensing indentation (nanoindentation). The technique is based on spherical indentation, which, in certain deformation regimes, can be much more sensitive to residual stress than indentation with sharp pyramidal indenters like the Berkovich. Two different methods of analysis were developed: one requiring an independent measure of the material's yield strength and the other a reference specimen in the unstressed state or other known reference condition. Experiments conducted on aluminum alloys to which controlled biaxial bending stresses were applied showed that the methods are capable of measuring the residual stress to within 10-20% of the specimen yield stress. Because the methods do not require imaging of the hardness impressions, they are potentially useful for making localized measurements of residual stress, as in thin films or small volumes, or for characterization of point-to-point spatial variations of the surface stress.

Journal ArticleDOI
TL;DR: In this paper, the authors used sharp indentation tests to explore how equi-biaxial residual stress and strain fields can be determined from the global properties, i.e., the size of the contact area between indenter and material and the hardness, given by such tests.

Journal ArticleDOI
TL;DR: In this paper, the design and optimization of a shunt capacitive micromachined switch with a thin metal membrane suspended over a center conductor, and fixed at both ends to the ground conductors of a coplanar waveguide (CPW) line is presented.
Abstract: Design and optimization of a shunt capacitive micromachined switch is presented. The micromachined switch consists of a thin metal membrane called the “bridge” suspended over a center conductor, and fixed at both ends to the ground conductors of a coplanar waveguide (CPW) line. A static electromechanical model considering the residual stress effects is developed to predict the effective stiffness constant and the critical collapse voltage of the bridge for several typical bridge geometries. The deformation of the bridge and its contact behavior with the dielectric layer are analyzed using the finite element method (FEM) in order to explore a good contact field with different bridge geometries. Furthermore, a nonlinear dynamic model that captures the effects of electrostatic forces, elastic deformation, residual stress, inertia, and squeeze film damping is developed, and is used for predicting the switching speed (including the switching-down and the switching-up time) and the Q -factor. The effects of variation of important parameters on the mechanical performance have been studied in detail, and the results are expected to be useful in the design of optimum shunt capacitive micromachined switch. The results may also be useful in the design of actuators with membranes or bridges.

Journal ArticleDOI
TL;DR: In this article, the influence of nitrogen/argon flow rate ratio, ion energy and ion/atom flux ratio on the microstructure, hardness, residual stresses and thermal stability of magnetron sputtered chromium nitride coatings was reported.
Abstract: Chromium nitride (CrN) is a hard material and a well-established coating for applications where severe corrosion and friction conditions are present. In this work, we report on the influence of nitrogen/argon flow rate ratio, ion energy and ion/atom flux ratio on the microstructure, hardness, residual stresses and thermal stability of magnetron sputtered chromium nitride coatings. The coatings were characterized with respect to thickness, morphology, chemical composition, microstructure and hardness. Hardness values up to 38.4 GPa could be obtained for stoichiometric CrN, which strongly depend on the grain size and residual stress. Thermal coating properties were evaluated using stress measurements during thermal cycling and XRD analyses after annealing at 500 and 700°C. Film stresses up to 700°C were measured from the bending of coated silicon specimens using the Stoney formula. Stress relaxation occurring during this temperature treatment strongly depends on the biaxial stresses in the as-deposited state. The interrelationships between growth conditions, microstructure, mechanical and thermal properties will be presented and discussed.

Journal ArticleDOI
TL;DR: The result of the study clearly established the relationship between bonding strength and residual stress and indicated that fracture of the system occurred mainly inside the hydroxyapatite coating under lower residual stress; as residual stress increased, fracture tended to occur more easily along the crucial HA-Ti alloy substrate interface.

Journal ArticleDOI
TL;DR: In this article, the authors describe the thermal elasto-plastic analysis using finite element techniques to analyse the thermomechanical behavior and evaluate the residual stresses and angular distortions of the T-joint in fillet welds.

Journal ArticleDOI
TL;DR: In this article, the energy release rate and mode mix for an interface delamination crack emerging from, or converging upon, an edge was analyzed for two two-dimensional configurations: (a) a film whose edge lies in the interior of the substrate and (b) a films whose edge is aligned with the edge of a substrate (i.e. the film/substrate geometry is a quarterplane).

Journal ArticleDOI
TL;DR: In this paper, the role of residual stresses on the mechanical integrity of physical vapour deposition (PVD) functional coatings is discussed and a numerical model of the residual stress distribution within a layered metal-ceramic composite coating is presented.

Journal ArticleDOI
TL;DR: In this article, a simplifying macroscopic constitutive law for ferroelectric and ferroelastic hysteresis effects of piezoceramics is presented.

Journal ArticleDOI
TL;DR: In this paper, the analytical and experimental study on the high-speed face milling of 7075-T6 aluminum alloys with a single insert fly-cutter was conducted.
Abstract: This research is concerned with the analytical and experimental study on the high-speed face milling of 7075-T6 aluminum alloys with a single insert fly-cutter. The results are analyzed in terms of cutting forces, chip morphology, and surface integrity of the workpiece machined with carbide and diamond inserts. It is shown that a high cutting speed leads to a high chip flow angle, very low thrust forces and a high shear angle, while producing a thinner chip. Chip morphology studies indicate that shear localization can occur at higher feeds even for 7075-T6, which is known to produce continuous chips. The resultant compressive residual stresses are shown for the variation of cutting parameters and cutting tool material. The analysis of the high-speed cutting process mechanics is presented, based on the calculation results using extended oblique machining theory and finite element simulation.

Journal ArticleDOI
TL;DR: In this article, a study of measurements of residual stresses on a single particle level was undertaken to enhance the understanding of this phenomenon, and the results were discussed with respect to the influence of each of these parameters, contribution of quenching and thermal stress component and splat formation.

Journal ArticleDOI
TL;DR: In this article, the residual stresses and residual damage caused by a spherical projectile impacting upon a flat surface were assessed by using a quasi-static numerical model and spatially resolved residual stress measurements to verify experimentally the numerical analysis.

Journal ArticleDOI
14 May 2001-Vacuum
TL;DR: In this paper, the authors investigated the role of thermal, intrinsic and extrinsic stresses in the formation of physical vapour deposition (PVD) films and found that tensile intrinsic stresses are usually observed in not fully dense films deposited by thermal evaporation from non-energetic particles.

Journal ArticleDOI
TL;DR: In this paper, the effect of residual stress on the G-peak position of the Raman spectrum has been investigated in both tetrahedral amorphous carbon (a-C:H) and hydrogenated a-c:H films.
Abstract: Tetrahedral amorphous carbon (ta-C) films deposited by the filtered vacuum arc process have large compressive residual growth stresses that depend on the atomic-bond structure. We observed that the G peak of the Raman spectrum shifts to higher frequency by 4.1±0.5 cm−1/GPa due to the residual compressive stress. This value agrees well with the calculated Raman-peak shift of the graphite plane due to applied stress. By considering the effect of residual stress on the G-peak position, we also observe a similar dependence between the G-peak position and the atomic-bond structure in both ta-C and hydrogenated amorphous carbon (a-C:H) films; namely, that a higher sp2 bond content shifts the G-peak position to higher frequency.

17 Jun 2001
TL;DR: In this paper, ultrasonic impact treatment (UIT) was used to enhance the fatigue resistance of welded transverse stiffeners and cover plate details in 18 full-scale W27×129 rolled beam specimens.
Abstract: Enhancement of the fatigue resistance of welded transverse stiffeners and cover plate details by ultrasonic impact treatment (UIT) was evaluated in 18 full-scale W27×129 rolled beam specimens. Fatigue tests were conducted under constant amplitude loading at various stress range levels and at two minimum stress levels simulating the effect of sustained load. The test specimens were investigated for fatigue crack initiation and propagation. Distributions of residual stresses adjacent to the weld toe were determined before and after the treatment. Test results indicated that UIT enhanced the fatigue performance of all treated details by improving the weld toe profile, changing microstructure and introducing beneficial compressive residual stresses at the treated weld toe. The treatment effectively elevated the fatigue crack growth threshold and the fatigue limit without changing the slope of the S–N curve.

Journal ArticleDOI
TL;DR: In this paper, a three dimensional coupled thermo-chemo-viscoelastic model is developed to simulate the heat transfer, curing, residual stresses and deformation of a composite part during the entire cure cycle.
Abstract: The warpage of thermoset composite structures during the manufacturing process is a direct consequence of residual stress development The capability to predict residual stresses is crucial to the manufacture of dimensionally accurate composite structures This paper is focused on understanding the fundamental issues leading to residual stresses in thermoset polymer composites and their effect on the dimensional accuracy of the manufactured components Unlike most existing work, which use simplified geometrical and/or material models or focused merely on the cooldown process, a three dimensional coupled thermo-chemo-viscoelastic model is developed to simulate the heat transfer, curing, residual stresses and deformation of a composite part during the entire cure cycle The predicted values of curvature for cross-ply graphite-epoxy laminates agree well with experimental observations The numerical result indicates that a significant fraction of the residual stress develops before cooldown Detailed studies

Journal ArticleDOI
TL;DR: In this paper, the shape memory effect of thin-film NiTi shape memory alloy (SMA) microactuator was investigated using both wet and dry etching techniques, and it was shown that wet etching the amorphous film produces a cleaner pattern than the crystallized film.
Abstract: Manufacturing issues related to a thin film NiTi shape memory alloy (SMA) microactuator (i.e. microwrapper) have been investigated using both wet and dry etching techniques. Results show that wet etching the amorphous film produces a cleaner pattern than the crystallized film. Transformation temperatures are not affected by the pre-exposure of the NiTi film to air before crystallization. However, this process produces breakage in the NiTi film at sacrificial layer steps. This is believed to be due to residual stresses developed between the film and substrate during sputtering. The film breakage is overcome by dry etching the film with an ion-milling technique. Curvature in the microwrapper arms is induced using either a bi-layer material (i.e. polyimide and NiTi) or a functionally gradated NiTi film. Results show that when heated the microwrapper arms flatten due to shape memory effect and curl up to form a cage-like structure when cooled.

Journal ArticleDOI
TL;DR: In this paper, the relationship between coating microstructure and properties in the Cr-C-N system has been investigated as a function of composition and post-deposition annealing, and the elastic modulus and hardness of asdeposited coatings were determined from nanoindentation to be 320 and 23 GPa, respectively, for moderate carbon concentrations (fR≤0.05).

Journal ArticleDOI
TL;DR: In this article, the magnitude of residual stresses in polycrystalline ceramics during processing was predicted using object oriented finite (OOF) element analysis and experimentally determined grain orientations.
Abstract: Microstructure-level residual stresses arise in polycrystalline ceramics during processing as a result of thermal expansion anisotropy and crystallographic disorientation across the grain boundaries. Depending upon the grain size, the magnitude of these stresses can be sufficiently high to cause spontaneous microcracking during the processing of these materials. They are also likely to affect where cracks initiate and propagate under macroscopic loading. The magnitudes of residual stresses in untextured and textured alumina samples were predicted using object oriented finite (OOF) element analysis and experimentally determined grain orientations. The crystallographic orientations were obtained by electron-backscattered diffraction (EBSD). The residual stresses were lower and the stress distributions were narrower in the textured samples compared to those in the untextured samples. Crack initiation and propagation were also simulated using the Griffith fracture criterion. The grain boundary to surface energy ratios required for computations were estimated using AFM groove measurements.