Bibliographies thématiques / Mixed hardening

Littérature scientifique sur le sujet « Mixed hardening »

Auteur : Grafiati

Publié le 23 décembre 2023

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Articles de revues sur le sujet "Mixed hardening"

Wu, Ze Yu, Xin Li Bai et Bing Ma. « 3-D Elastic-Plastic Constitutive Relationship of Mixed Hardening ». Applied Mechanics and Materials 249-250 (décembre 2012) : 927–30. http://dx.doi.org/10.4028/www.scientific.net/amm.249-250.927.

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In finite element calculation of plastic mechanics, isotropic hardening model, kinematic hardening model and mixed hardening model have their advantages and disadvantages as well as applicability area. In this paper, by use of the tensor analysis method and mixed hardening theory in plastic mechanics, the constitutive relation of 3-D mixed hardening problem is derived in detail based on the plane mixed hardening. Numerical results show that, the proposed 3-D mixed hardening constitutive relation agrees well with the test results in existing references, and can be used in the 3-D elastic-plastic finite element analysis.

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Rentmeester, Rikard, et Larsgunnar Nilsson. « On mixed isotropic-distortional hardening ». International Journal of Mechanical Sciences 92 (mars 2015) : 259–68. http://dx.doi.org/10.1016/j.ijmecsci.2014.09.013.

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Cai, Xing Zhou, Lin Feng Wang, Shi Yan Zhao, Bao Feng Guo et Yu Xin Zhu. « Research on the Reverse Loading Hardening Model of the X80 Pipeline Steel ». Advanced Materials Research 750-752 (août 2013) : 370–74. http://dx.doi.org/10.4028/www.scientific.net/amr.750-752.370.

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Based on the reverse uniaxial loading test, the influences of the plastic deformation on the strength properties are studied. The softening of the X80 pipeline steel is observed which reveals the hardening type is mixed hardening. The expression of mixed hardening factor M and the material parameters of the nonlinear mixed hardening model under different M can be obtained. The results show that, if the pre-strain increases and ranges from 0.55% to 2.5%, the mixed hardening characteristics of the X80 pipeline steel will be more obvious and its M will also increase.

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Rezaiee‐Pajand, Mohammad, Cyrus Nasirai et Mehrzad Sharifian. « Integration of nonlinear mixed hardening models ». Multidiscipline Modeling in Materials and Structures 7, n^o 3 (27 septembre 2011) : 266–305. http://dx.doi.org/10.1108/1536-540911178252.

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Abduljauwad, Sahel N., Isa M. Al‐Buraim et Hamdan N. Al‐Ghamedy. « Mixed Hardening, Three‐Invariants Dependent Cap Model ». Journal of Engineering Mechanics 118, n^o 3 (mars 1992) : 620–37. http://dx.doi.org/10.1061/(asce)0733-9399(1992)118:3(620).

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Bathe, Klaus-Jürgen, et Francisco Javier Montáns. « On modeling mixed hardening in computational plasticity ». Computers & ; Structures 82, n^o 6 (mars 2004) : 535–39. http://dx.doi.org/10.1016/j.compstruc.2003.08.010.

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Chen, Guang, Changcai Zhao, Haiwei Shi, Qingxing Zhu, Guoyi Shen, Zheng Liu, Chenyang Wang et Duan Chen. « Research on the 2A11 Aluminum Alloy Sheet Cyclic Tension–Compression Test and Its Application in a Mixed Hardening Model ». Metals 13, n^o 2 (26 janvier 2023) : 229. http://dx.doi.org/10.3390/met13020229.

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The increasing application of aluminum alloy, in combination with the growth in the complexity of components, provides new challenges for the numerical modeling of sheet materials. The material elastic–plasticity constitutive model is the most important factor affecting the accuracy of finite element simulation. The mixed hardening constitutive model can more accurately represent the real hardening characteristics of the material plastic deformation process, and the accuracy of the material property-related parameters in the constitutive model directly affects the accuracy of finite element simulation. Based on the Hill48 anisotropic yield criterion, combined with the Voce isotropic hardening model and the Armstrong–Frederic nonlinear kinematic hardening model, a mixed hardening constitutive model that considers material anisotropy and the Bauschinger effect was established. Analysis of the tension–compression experiment on the sheet using finite element method. Using the finite element model, the optimum geometry of the tension–compression experiment sample was determined. The cyclic deformation stress–strain curve of the 2A11 aluminum alloy sheet was obtained by a cyclic tensile–compression test, and the material characteristic parameters in the mixed hardening model were accurately determined. The reliability and accuracy of the established constitutive model of anisotropic mixed hardening materials were verified by the finite element simulation and by testing the cyclic tensile–compression problem, the springback problem, and the sheet in bending, unloading, and reverse bending problems. The tensile–compression experiment is an effective method to directly and accurately obtain the characteristic parameters of constitutive model materials.

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Muránsky, Ondrej, Cory J. Hamelin, Mike C. Smith, Phillip J. Bendeich et Lyndon Edwards. « The Role of Plasticity Theory on the Predicted Residual Stress Field of Weld Structures ». Materials Science Forum 772 (novembre 2013) : 65–71. http://dx.doi.org/10.4028/www.scientific.net/msf.772.65.

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Constitutive plasticity theory is commonly applied to the numerical analysis of welds in one of three ways: using an isotropic hardening model, a kinematic hardening model, or a mixed isotropic-kinematic hardening model. The choice of model is not entirely dependent on its numerical accuracy, however, as a lack of empirical data will often necessitate the use of a specific approach. The present paper seeks to identify the accuracy of each formalism through direct comparison of the predicted and actual post-weld residual stress field developed in a three-pass 316LN stainless steel slot weldment. From these comparisons, it is clear that while the isotropic hardening model tends to noticeably over-predict and the kinematic hardening model slightly under-predict the residual post-weld stress field, the results using a mixed hardening model are quantitatively accurate. Even though the kinematic hardening model generally provides more accurate results when compared to an isotropic hardening formalism, the latter might be a more appealing choice to engineers requiring a conservative design regarding weld residual stress.

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Teng-xi, Liu, Huang Shi-qing et Fu Yi-ming. « The constitutive equations for mixed hardening orthotropic material ». Applied Mathematics and Mechanics 24, n^o 2 (février 2003) : 216–20. http://dx.doi.org/10.1007/bf02437628.

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Mo, Yafei, Rou Du et Xiaoming Liu. « Effect of mixed plastic hardening on the cyclic contact between a sphere and a rigid flat ». Journal of Physics : Conference Series 2285, n^o 1 (1 juin 2022) : 012018. http://dx.doi.org/10.1088/1742-6596/2285/1/012018.

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Abstract This paper studies the effect of mixed plasticity mode (combined with isotropic and kinematic hardening law) on the cyclic contact between an elastic-plastic sphere and a rigid flat. Assuming power-law hardening with different levels of mixed plasticity for the sphere, we derived a semi-analytical expression of load versus interference during the first loading and unloading process. During cyclic loading, our results indicate that the isotropic plasticity model shows no variation of residual interference, while kinematic plasticity has the cyclic effect on the residual interference, and this effect is bigger for the material with a higher hardening exponent. In addition, we provided the semi-analytical expression for the evolution of residual interference, which is accurate for the strain hardening exponent from 0.1 to 0.5.

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Thèses sur le sujet "Mixed hardening"

Cardoso, Adilson Silva. « Design and characterization of BiCMOS mixed-signal circuits and devices for extreme environment applications ». Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53099.

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State-of-the-art SiGe BiCMOS technologies leverage the maturity of deep-submicron silicon CMOS processing with bandgap-engineered SiGe HBTs in a single platform that is suitable for a wide variety of high performance and highly-integrated applications (e.g., system-on-chip (SOC), system-in-package (SiP)). Due to their bandgap-engineered base, SiGe HBTs are also naturally suited for cryogenic electronics and have the potential to replace the costly de facto technologies of choice (e.g., Gallium-Arsenide (GaAs) and Indium-Phosphide (InP)) in many cryogenic applications such as radio astronomy. This work investigates the response of mixed-signal circuits (both RF and analog circuits) when operating in extreme environments, in particular, at cryogenic temperatures and in radiation-rich environments. The ultimate goal of this work is to attempt to fill the existing gap in knowledge on the cryogenic and radiation response (both single event transients (SETs) and total ionization dose (TID)) of specific RF and analog circuit blocks (i.e., RF switches and voltage references). The design approach for different RF switch topologies and voltage references circuits are presented. Standalone Field Effect Transistors (FET) and SiGe HBTs test structures were also characterized and the results are provided to aid in the analysis and understanding of the underlying mechanisms that impact the circuits' response. Radiation mitigation strategies to counterbalance the damaging effects are investigated. A comprehensive study on the impact of cryogenic temperatures on the RF linearity of SiGe HBTs fabricated in a new 4th-generation, 90 nm SiGe BiCMOS technology is also presented.

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Thuillet, Stéphanie. « Modélisation de lois de comportement pour le micro-formage de tôles ultra-fines ». Electronic Thesis or Diss., Lorient, 2023. http://www.theses.fr/2023LORIS655.

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La miniaturisation fait maintenant partie intégrante des problématiques actuelles de notre société. Afin de combler l'attente des industries demandeuses de plus en plus de composants de petites tailles, tout en respectant des délais de fabrication courts, les procédés par déformation plastique se sont révélés être les plus efficaces. Pour éviter de nombreux tests expérimentaux la simulation de ces procédés est une alternative importante. L'objectif de cette thèse vise à la définition d'une loi de comportement dédiée aux tôles ultra-fines d'alliages cuivreux présents dans les industries et en particulier l'horlogerie. Une campagne expérimentale est ainsi menée dans le but d'observer le comportement de tôles en cuivre de 0,25 mm d'épaisseur et d'un alliage de cuivre béryllium de 0,20 mm d'épaisseur. La caractérisation microstructurale permet de valider le cadre des tôles ultra-fines grâce à l'étude du nombre et de la taille des grains dans l'épaisseur. Les tests expérimentaux mettent quant à eux en avant le comportement isotrope du cuivre, le CuBe possède pour sa part un comportement anisotrope et une prédominance d'écrouissage cinématique. En relation avec les observations expérimentales, deux modèles utilisant une loi élastoviscoplastique sont proposés et comparés, un dans le cadre de la plasticité associée et l'autre employant la plasticité non-associée. Ces modèles prennent notamment en compte un écrouissage mixte. Les paramètres matériaux sont ensuite identifiés à l'aide d'un algorithme de minimisation. Les différentes analyses sur les méthodes de simulations et d'identification indiquent que le modèle de plasticité non-associée est le plus adapté. Des simulations et identifications sur des éléments de volume représentatifs sont suffisantes dans notre cas. Enfin différents procédés de mise en forme sont étudiés et simulés grâce à l'implémentation de la loi de comportement proposée dans un code de calcul par la méthode des éléments finis. Ils mettent en évidence le développement du modèle proposé permettant de prendre en compte un écrouissage mixte. Ce modèle peut donc être utilisé pour la simulation de procédés de mise en forme de tôles ultra-fines d'alliages cuivreux de petites dimensions sous sollicitations complexes
Miniaturization is now an integral part of the current issues of our society. To meet industries expectation which are looking for more small-sized components with shorter manufacturing deadlines, plastic deformation processes have proven to be the most effective. To avoid a lot of experimental tests, simulation of these processes is an important alternative. The goal of this thesis is to define a behaviour law dedicated to ultra-thin sheets of copper alloys which are present in industries and particularly in the watchmaking industry. An experimental campaign is thus carried out to notice the behaviour of a of 0,25 mm thick copper sheet and of a 0,20 mm thick copper beryllium alloy. The micro-structural characterisation makes it possible to validate the framework of ultra-thin sheets thanks to the study of the number and size of the grains in the thickness. Experimental tests highlight the isotropic behaviour of copper. The CuBe has an anisotropic behaviour and a predominance of kinematic work hardening. Regarding to the experimental observations, two models using an elastoviscoplastic law are proposed and compared, one within the framework of associated plasticity and the other employing non-associated plasticity. These models especially take into account a mixed work hardening. Material parameters are then identified using a minimisation algorithm. The different analyses on the simulation and identification methods indicate that the non-associated plasticity model is the most suitable. Simulations and identifications on representative volume elements are sufficient in our case. Finally, the several forming processes are studied and simulated thanks to the implementation of behaviour laws in a computer code by the finite element method. They highlight the development of the proposed model allowing to take into account a mixed work hardening. This model can therefore be used for the simulation of forming processes of ultra-thin sheets, especially of small-sized copper alloys under complex stresses

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ADHIKARI, THAM. « QUALITY AND DURABILITY OF RUBBERIZED ASPHALT CEMENT AND WARM RUBBERIZED ASPHALT CEMENT ». Thesis, 2013. http://hdl.handle.net/1974/7921.

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This thesis discusses and documents findings from an investigation of performance-based testing of asphalt cement (AC), warm mixed asphalt cement, asphalt rubber (AR), and warm asphalt rubber. A number of control, warm, and asphalt rubber binders from Ontario construction contracts were investigated for their compliance with conventional Superpave® test methods such as rolling thin film (RTFO), pressure aging vessel (PAV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR), as well as additional specification tests such as extended BBR and double edge notched tension test. The quality and durability of those binders were determined. Quality means the ability of asphalt binder to reach a set of specific properties whereas durability is the measure of how well asphalt retains its original characteristics when exposed to normal weathering and aging process. One warm AC and two field-blended asphalt rubber samples showed high levels of physical hardening which can lead to premature and early cracking. The warm asphalt cement lost 8 °C when stored isothermally for three days at low temperatures according to Ontario’s extended bending beam rheometer (BBR) protocol (LS-308). The two asphalt rubber samples lost 10 °C and 12 °C following the same conditioning. Many of the studied asphalt samples showed deficient strain tolerance as measured in Ontario’s double-edge-notched tension (DENT) test (LS-299). In a study of warm rubberized asphalt cement with improved properties, a number of compositions were prepared with soft Cold Lake AC and a small quantity of naphthenic oil. These binders showed little chemical and physical hardening and reasonable critical crack tip opening displacements (CTOD). Strain tolerance was much improved by co-blending with a high vinyl type styrene-butadiene-styrene (SBS) polymer and a small amount of sulfur.
Thesis (Master, Chemistry) -- Queen's University, 2013-04-24 22:54:20.07

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Chapitres de livres sur le sujet "Mixed hardening"

Galdos, Lander, Julen Agirre, Nagore Otegi, Joseba Mendiguren et Eneko Saenz de Argandoña. « Simulation of Cold Forging Processes Using a Mixed Isotropic-Kinematik Hardening Model ». Dans Forming the Future, 773–87. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-75381-8_64.

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Hajiesmaeili, Amir, et Emmanuel Denarié. « Effect of Fiber Orientation and Specimen Thickness on the Tensile Response of Strain Hardening UHPFRC Mixes with Reduced Embodied Energy ». Dans Strain-Hardening Cement-Based Composites, 324–32. Dordrecht : Springer Netherlands, 2017. http://dx.doi.org/10.1007/978-94-024-1194-2_38.

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di Prisco, C., R. Nova et J. Lanier. « A Mixed Isotropic-Kinematic Hardening Constitutive Law for Sand ». Dans Modern Approaches to Plasticity, 83–124. Elsevier, 1993. http://dx.doi.org/10.1016/b978-0-444-89970-5.50010-8.

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Romero, E., et C. Jommi. « Mixed isotropic-rotational hardening to model the deformational response of unsaturated compacted soils ». Dans Unsaturated Soils. Advances in Geo-Engineering, 617–23. Taylor & Francis, 2008. http://dx.doi.org/10.1201/9780203884430.ch83.

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Lee, J. H. « On Numerical Integration of a Class of Pressure-Sensitive Plasticity Models with Mixed Hardening ». Dans Advances in Plasticity 1989, 621–24. Elsevier, 1989. http://dx.doi.org/10.1016/b978-0-08-040182-9.50152-1.

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Xiaying, Mu, et Li Zhouli. « EXACT INTEGRAL METHOD FOR CONSTITUTIVE EQUATIONS OF THE MIXED HARDENING MODEL UNDER CYCLIC LOADING ». Dans Advances in Engineering Plasticity and its Applications, 659–64. Elsevier, 1993. http://dx.doi.org/10.1016/b978-0-444-89991-0.50089-5.

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Amorosi, A. « Implicit integration of a new hyperelastic mixed isotropic-kinematic hardening model for structured clays ». Dans Numerical Methods in Geotechnical Engineering, 121–25. Taylor & Francis, 2006. http://dx.doi.org/10.1201/9781439833766.ch17.

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NOWLIN, NATHAN, JOHN BAILEY, BOB TURFLER et DAVE ALEXANDER. « A TOTAL-DOSE HARDENING-BY-DESIGN APPROACH FOR HIGH-SPEED MIXED-SIGNAL CMOS INTEGRATED CIRCUITS ». Dans Selected Topics in Electronics and Systems, 83–94. WORLD SCIENTIFIC, 2004. http://dx.doi.org/10.1142/9789812794703_0007.

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Cantor, Brian. « The Burgers Vector ». Dans The Equations of Materials, 226–48. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198851875.003.0011.

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When a material is stretched beyond its elastic limit, the atoms and molecules begin to slide over each other. This is called plasticity, and is dominated by the motion of defects in the crystal structure of the material, notably line defects called dislocations. The structure and magnitude of a dislocation is defined by its Burgers vector, which is a topological constant for a given dislocation line in a given material, so there is an effective Burgers equation: b = constant. This chapter describes: the structure of edge; screw and mixed dislocations and their associated line energy; the way in which dislocations are generated and interact under stress, leading to the yield point, work hardening and a permanent set in the material; and the use during manufacturing of deformation processing, annealing, recovery and recrystallisation. Jan Burgers’ early life in Arnhem at the beginning of the 20th century is described, as are: his time as a student with the charismatic but depressive Paul Ehrenfest, who later committed suicide; his appointment as the first Professor of Aerodynamics at Technische Universiteit Delft at a time of massive growth in the aviation industry; his contributions to aerodynamic and hydrodynamic flow as well as major Dutch engineering projects such as the Zuiderzee dams and the Maas river tunnel; his growing disaffection with the commercialisation of science and its use in warfare; and his philosophical dalliance with Soviet communism and then American capitalism.

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Actes de conférences sur le sujet "Mixed hardening"

Li, Qun, Miao Jin et Zhu Yuxin. « Analysis on sheet cyclic plastic deformation using mixed hardening model ». Dans THE 11TH INTERNATIONAL CONFERENCE ON NUMERICAL METHODS IN INDUSTRIAL FORMING PROCESSES : NUMIFORM 2013. AIP, 2013. http://dx.doi.org/10.1063/1.4806940.

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Mullins, Jonathan, et Jens Gunnars. « Welding Simulation : Relationship Between Welding Geometry and Determination of Hardening Model ». Dans ASME 2012 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/pvp2012-78599.

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It is generally acknowledged that the material hardening model exerts a considerable effect on predicted weld residual stress fields. For this reason the choice of hardening model has attracted interest among analysts, particularly during recent validation studies. Nevertheless there is still lack of evidence for a hardening model which is generally applicable for all welding geometries. In this work we examine the predictions of nonlinear kinematic, isotropic and mixed hardening models for two different geometries: a single bead on plate weld, and a multi-bead girth weld. Hardening parameters are based on the same openly available mechanical test data. Deformation histories for the two welding geometries are presented. Predicted residual stress profiles are compared with experimental measurements. It is noted that nonlinear kinematic hardening results in good predictions for the single bead welding simulation where hardening in the weld and HAZ is dominated by a single heating and cooling cycle. Isotropic hardening results in good predictions for the 42 bead girth weld, where hardening in the weld and HAZ is heavily influenced by several heating and cooling cycles from the addition of several weld beads and where some relaxation of residual stress is possible. Mixed hardening can result in good predictions for both welding geometries. Additional strategies for development of material models based on isotropic and kinematic hardening and relevant test data are discussed with particular attention paid to intermediate weld geometries.

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Sureau, Mathieu, Russell Stevens, Marco Leuenberger, Nadia Rezzak et Dorian Johnson. « TID, ELDRS and SEE Hardening and Testing on Mixed Signal Telemetry LX7730 Controller ». Dans 2017 IEEE Nuclear & Space Radiation Effects Conference (NSREC) : Radiation Effects Data Workshop (REDW). IEEE, 2017. http://dx.doi.org/10.1109/nsrec.2017.8115478.

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Sureau, Mathieu, Russell Stevens, Marco Leuenberger, Nadia Rezzak, Dorian Johnson et Kathy Zhang. « Extended TID, ELDRS and SEE Hardening and Testing on Mixed Signal Telemetry LX7730 Controller ». Dans 2017 17th European Conference on Radiation and Its Effects on Components and Systems (RADECS). IEEE, 2017. http://dx.doi.org/10.1109/radecs.2017.8696179.

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Yanagida, Nobuyoshi. « Study on Stress-Strain Relation for Type 316L Stainless Steel Using Mixed Hardening Law ». Dans ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61404.

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To determine stress-strain diagrams for a pipe butt joint of type 316L stainless steel, stress-strain diagrams for pipe specimens subjected to monotonic uniaxial tensile load were measured. Tensile-test specimens were extracted from the deposited metal area, heat-affected zone, and parent-material area of the pipe butt joint. The specimens of the deposited-metal area and the heat-affected zone were extracted from positions at the pipe inner surface, mid-thickness, and the pipe outer surface. The measurement temperatures were 20, 300, 600, and 800°C. The measured stress-strain diagrams show that measured stress at the same given strain increases from measurement point on the outer surfer of the pipe to that on the inner surface. This stress increase is thought to be related to the number of thermal-load cycles used for the weld. The number of cycles at the pipe inner surface was greater than that at the pipe outer surface. To use the measured stress-strain diagrams in a thermal elasto-plastic analysis of welding residual stress and distortion, the measured diagrams for the deposited-metal-area pipe specimen and the parent-material-area pipe specimen were fitted to calculated diagrams by using an isotropic/kinematic mixed hardening law. Material constants for approximating the stress-strain diagrams for the parent-material specimen and deposited-metal specimen were determined. The calculated stress-strain diagrams derived from the isotropic/kinematic mixed hardening law show good agreement with the measured stress-strain diagrams.

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Chow, C. L., et X. J. Yang. « A Generalized Mixed Kinematic-Isotropic Hardening Plastic Model Coupled With Anisotropic Damage for Sheet Metal Forming ». Dans ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-33019.

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The paper presents a generalized mixed isotropic-kinematic hardening plastic model coupled with anisotropic damage for sheet metal forming. A nonlinear anisotropic kinematic hardening is developed. For the predication of limit strains at localized necking in stamping under complex strain history, the model and its associated damage criterion for localized necking are established and implemented into LS-DYNA3D by compiling it as a user subroutine. The finite element simulation of LS-DYNA3D based on the present model is carried out. The location of localized necking for sheet metal forming has been successfully identified.

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Novak, Jiri. « Ductile Fracture of Ferritic Steels : Correlation of KIIc/KIc Ratio and Strain Hardening Curve ». Dans ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1342.

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Recently, interest on fracture toughness under mixed mode loading increases and many questions remain to be answered, especially for ductile fracture. Crack growth resistance curves for mixed mode loading may be interpreted as a result of competition between usual ductile fracture and shear fracture. Analysis is based on previous work in the field of ductile fracture, especially on studies of ductile fracture criteria of the type “loss of stability of homogeneous deformation field”. Phenomena of shear fracture can be successfully predicted by bifurcation analysis of shear band initiation or localized necking. Usual ductile fracture under different stress triaxialities can be analogously predicted by cavitation instability criterion. Usual (cavitation-type) ductile fracture strain depends on strain hardening exponent less than shear fracture strain does and this explains dependence of the KIIc/KIc ratio on strain hardening exponent. These ideas are demonstrated quantitatively using data in the open literature.

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Ghavam, Kamyar, et Reza Naghdabadi. « Corotational Analysis of Elastic-Plastic Hardening Materials Based on Different Kinematic Decompositions ». Dans ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93442.

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In this paper, two corotational modeling for elastic-plastic, mixed hardening materials at finite deformations are introduced. In these models, the additive decomposition of the strain rate tensor as well as the multiplicative decomposition of the deformation gradient tensor is used. For this purpose, corotational constitutive equations are derived for elastic-plastic hardening materials with the non-linear Armstrong-Frederick kinematic hardening and isotropic hardening models. As an application of the proposed constitutive modeling, the governing equations are solved numerically for the simple shear problem with different corotational rates and the stress components are plotted versus the shear displacement. The results for stress, using the additive and the multiplicative decompositions are compared with those obtained experimentally by Ishikawa [1]. This comparison shows a good agreement between the proposed theoretical models and the experimental data. As another example, the Prager kinematic hardening equation is used instead of the Armstrong-Frederick model. In this case the results for stress are compared with the theoretical results of Bruhns et al. [2].

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Duchêne, Laurent. « Analysis of Texture Evolution and Hardening Behavior during Deep Drawing with an Improved Mixed Type FEM Element ». Dans NUMISHEET 2005 : Proceedings of the 6th International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Process. AIP, 2005. http://dx.doi.org/10.1063/1.2011254.

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Qiao, Dongxiao, Zhili Feng, Wei Zhang, Yanli Wang et Paul Crooker. « Modeling of Weld Residual Plastic Strain and Stress in Dissimilar Metal Butt Weld in Nuclear Reactors ». Dans ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-98081.

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Primary water stress corrosion cracking (PWSCC) constitutes a major safety challenge for dissimilar metal welds (DMW) in pressurized water reactors. The reliability of structure integrity assessment of DMW is strongly dependent on the reliable determination of the weld residual stress (WRS) field, which is one of the primary driving forces for PWSCC. Recent studies have shown that today’s WRS models have varying degrees of success in determining the WRS in DMW that is highly dependent upon the strain-hardening models used in WRS simulation. The commonly used strain hardening model in WRS modeling (isotropic, kinematic, and mixed ones) appear to be inadequate in that they neglect the high-temperature time-dependent (viscous) deformation process during welding. This work presents a new strain-hardening model derived from specially designed experiment that mimics the thermal-mechanical deformation process of a SS304L stainless steel under rapid heating and cooling conditions relevant to DMW. Compared to the time-independent strain hardening ones, the new strain hardening model, termed as Dynamic Strain Hardening model, takes into account the effect of time and temperature dependent dislocation annihilation and microstructure recrystallization processes at the elevated temperatures during welding. Moreover, a novel experimental approach based on micro-hardness testing is developed to quantify the residual equivalent plastic strain in a mock-up DMW. It is found that the new dynamic strain hardening model produces results that are more consistent with experimentally measured plastic strains and residual stresses. It is concluded that it is necessary to include the dynamic strain hardening recovery phenomenon to improve the accuracy of WRS predictions in DMW. Moreover, the newly developed micro-hardness based plastic strain measurement approach would be an effective means to quantify the plastic strain distributions which is another key factor for PWSCC in DMW in addition to the residual stresses.

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Rapports d'organisations sur le sujet "Mixed hardening"

Ramakrishnan, Aravind, Ashraf Alrajhi, Egemen Okte, Hasan Ozer et Imad Al-Qadi. Truck-Platooning Impacts on Flexible Pavements : Experimental and Mechanistic Approaches. Illinois Center for Transportation, novembre 2021. http://dx.doi.org/10.36501/0197-9191/21-038.

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Truck platoons are expected to improve safety and reduce fuel consumption. However, their use is projected to accelerate pavement damage due to channelized-load application (lack of wander) and potentially reduced duration between truck-loading applications (reduced rest period). The effect of wander on pavement damage is well documented, while relatively few studies are available on the effect of rest period on pavement permanent deformation. Therefore, the main objective of this study was to quantify the impact of rest period theoretically, using a numerical method, and experimentally, using laboratory testing. A 3-D finite-element (FE) pavement model was developed and run to quantify the effect of rest period. Strain recovery and accumulation were predicted by fitting Gaussian mixture models to the strain values computed from the FE model. The effect of rest period was found to be insignificant for truck spacing greater than 10 ft. An experimental program was conducted, and several asphalt concrete (AC) mixes were considered at various stress levels, temperatures, and rest periods. Test results showed that AC deformation increased with rest period, irrespective of AC-mix type, stress level, and/or temperature. This observation was attributed to a well-documented hardening–relaxation mechanism, which occurs during AC plastic deformation. Hence, experimental and FE-model results are conflicting due to modeling AC as a viscoelastic and the difference in the loading mechanism. A shift model was developed by extending the time–temperature superposition concept to incorporate rest period, using the experimental data. The shift factors were used to compute the equivalent number of cycles for various platoon scenarios (truck spacings or rest period). The shift model was implemented in AASHTOware pavement mechanic–empirical design (PMED) guidelines for the calculation of rutting using equivalent number of cycles.

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LOW-CYCLE FATIGUE PROPERTIES OF AUSTENITIC STAINLESS STEEL S30408 UNDER LARGE PLASTIC STRAIN AMPLITUDE. The Hong Kong Institute of Steel Construction, mars 2022. http://dx.doi.org/10.18057/ijasc.2022.18.1.10.

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The application of stainless steel materials in civil structures for seismic protection lies in its low-cycle fatigue characteristic. However, the data of existing research are mainly based on the low-cycle fatigue in small strain amplitudes. To this end, we perform low-cycle fatigue testing of Austenitic stainless steel S30408, which has low yield point and good elongation performance, under the cyclic load with a maximum strain amplitude reaching up to 5%, to fill the gap. The stress-strain response characteristics of the stainless steel material under the cyclic load are analyzed; then, the parameters of the strain-fatigue life relationship and the cyclic-plastic constitutive model used for FEA simulation are extracted. Results show that the stainless steel’s stress-strain curve is nonlinear without a yield plateau, thus presenting a high strength yield ratio and ductility. The hysteresis loops of the material are plump with a shuttle shape and are symmetric to the origin, indicating a fine energy dissipation capacity. The skeleton curve under cyclic loading with cyclic hardening can be significantly reflected by the Ramberg Osgood model, which is affected by the strain amplitude and loading history; it is also different from the monotonic tensile skeleton curve. The strain-fatigue life curve fitted by the Baqusin Manson Coffin model can predict the materials’ fatigue life under different strain amplitudes. The mixed hardening model, including isotropic and kinematic hardening, based on the Chaboche model, is able to simulate the cyclic stress-strain relationship. Further, its parameters can provide basic data information for the seismic design of civil structures when Austenitic stainless steel S30408 is used.

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