Literatura científica selecionada sobre o tema "Elasto-Visco-Plastic behavior"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Consulte a lista de atuais artigos, livros, teses, anais de congressos e outras fontes científicas relevantes para o tema "Elasto-Visco-Plastic behavior".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Artigos de revistas sobre o assunto "Elasto-Visco-Plastic behavior"
1
Ewoldt, Randy H., e Gareth H. McKinley. "Mapping thixo-elasto-visco-plastic behavior". Rheologica Acta 56, n.º 3 (março de 2017): 195–210. http://dx.doi.org/10.1007/s00397-017-1001-8.
Texto completo da fonte
2
Wan, Lin Hui, Ping Cao, Yong Heng Huang, Yi Xian Wang e Xiang Yang Zhang. "Creep Test of Hard Rock and Modified Generalized Kelvin Creep Model". Applied Mechanics and Materials 90-93 (setembro de 2011): 626–32. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.626.
Texto completo da fonteResumo:
By a circular increment step load and unload method, a set of rheological experiments were performed to study the creep properties of amphibolite and the deformation data of instantaneous elasticity, instantaneous plasticity, viscoplasticity and viscoelasticity could be obtained. The results showed that: the creep threshold of amphibolite(σs1) was 25.46MPa; whenσs1s2, the proportion of plastic deformation in the total deformation was very small and the value of creep deformation always tended to a stable value; whenσ>σs2, the rock samples failed rapidly and had no obvious creep. According to the creep and failure properties of amphibolite, the generalized Kelvin creep model was acted in series with the Mohr-Coulomb criterion and a modified generalized Kelvin creep model was built and the corresponding visco-elasto-plastic constitutive relationships were deduced. The modified model could simulate visco-elasto-plastic deviatoric behavior and elasto-plastic volumetric behavior. The model parameters of amphibolite were fitted according to the data of rheological test. The testing curves were coincident well with the theoretic curves by comparison which showed the creep properties and the plastic flow of hard rock could be well simulated by the generalized Kelvin creep model.
3
Jeong, Youngung, e Carlos N. Tomé. "Extension of the visco-plastic self-consistent model to account for elasto-visco-plastic behavior using a perturbed visco-plastic approach". Modelling and Simulation in Materials Science and Engineering 27, n.º 8 (1 de outubro de 2019): 085013. http://dx.doi.org/10.1088/1361-651x/ab4b66.
Texto completo da fonte
4
Ju, J. W., e Tsung-Muh Chen. "Micromechanics and Effective Elastoplastic Behavior of Two-Phase Metal Matrix Composites". Journal of Engineering Materials and Technology 116, n.º 3 (1 de julho de 1994): 310–18. http://dx.doi.org/10.1115/1.2904293.
Texto completo da fonteResumo:
A micromechanical framework is presented to predict effective (overall) elasto-(visco-)plastic behavior of two-phase particle-reinforced metal matrix composites (PRMMC). In particular, the inclusion phase (particle) is assumed to be elastic and the matrix material is elasto-(visco-)plastic. Emanating from Ju and Chen’s (1994a,b) work on effective elastic properties of composites containing many randomly dispersed inhomogeneities, effective elastoplastic deformations and responses of PRMMC are estimated by means of the “effective yield criterion” derived micromechanically by considering effects due to elastic particles embedded in the elastoplastic matrix. The matrix material is elastic or plastic, depending on local stress and deformation, and obeys general plastic flow rule and hardening law. Arbitrary (general) loadings and unloadings are permitted in our framework through the elastic predictor-plastic corrector two-step operator splitting methodology. The proposed combined micromechanical and computational approach allows us to estimate overall elastoplastic responses of PRMMCs by accounting for the microstructural information (such as the spatial distribution and micro-geometry of particles), elastic properties of constituent phases, and the plastic behavior of the matrix-only materials. Comparison between our theoretical predictions and experimental data on uniaxial elastoplastic tests for PRMMCs is also presented to illustrate the capability of the proposed framework. A straightforward extension to accommodate viscoplastic matrix material is also presented to further enhance the applicability of the proposed method.
5
Milašinović, Dragan D. "Rheological–dynamical analogy: visco-elasto-plastic behavior of metallic bars". International Journal of Solids and Structures 41, n.º 16-17 (agosto de 2004): 4599–634. http://dx.doi.org/10.1016/j.ijsolstr.2004.02.061.
Texto completo da fonte
6
Liu, Sheng, Tong Liu, Bang Zhe Liu e Zi Chao Dong. "Numerical Simulation of Creep Deformation for Large Section Tunnel in Soil with Visco-Elastic-Plastic FEM". Advanced Materials Research 368-373 (outubro de 2011): 2500–2503. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2500.
Texto completo da fonteResumo:
In order to reasonably analyze the influence of rheological properties on the soil deformation behavior of tunnel in soil, this paper establishes visco-elastic-plastic numerical calculation model for analysis of tunnel in soil deformation based on ANSYS software by relying on physical construction. The results show that creep deformation accounts for 24% of total deformation of the tunnel, so it is necessary to make visco-elasto-plastic analysis on tunnel in soil. If the numerical simulation results are basically the same with the trend of temporal curve of measured data, and the data obtained is relatively close, then the established model is correct.
7
Slouf, Miroslav, Milos Steinhart, Pavel Nemecek, Veronika Gajdosova e Jiri Hodan. "Correlations between Microscale Indentation Creep and Macroscale Tensile Creep of Polymers". Materials 16, n.º 2 (15 de janeiro de 2023): 834. http://dx.doi.org/10.3390/ma16020834.
Texto completo da fonteResumo:
We compared the results of various microscale indentation creep (microcreep) measurements with macroscale tensile creep (macrocreep) measurements of three common polymers: high-density polyethylene (PE), polypropylene (PP), and polystyrene (PS). The main objective was to verify if the short-term microcreep experiments could predict long-term macrocreep behavior of the selected polymers, whose properties ranged from very soft and ductile (PE) to very hard and brittle (PS). The second objective was to compare several creep predictive schemes: the empirical power law model (PL) and several types of phenomenological elasto-visco-plastic models (EVP). In order to facilitate this task, we developed a universal program package named MCREEP, which fits PL and EVP models to both tensile and indentation creep data. All experimental results and theoretical predictions documented that: (i) regardless of the creep experiment type, both micro- and macrocreep resistance increased in the following order: PE < PP < PS, (ii) the short-term microcreep experiments could be used to predict qualitatively the long-term macrocreep behavior, and (iii) the simple empirical power law model yielded better predictions of long-term creep behavior than the more sophisticated elasto-visco-plastic models.
8
Wang, Xingkai, Leibo Song, Caichu Xia, Guansheng Han e Zheming Zhu. "Nonlinear Elasto-Visco-Plastic Creep Behavior and New Creep Damage Model of Dolomitic Limestone Subjected to Cyclic Incremental Loading and Unloading". Sustainability 13, n.º 22 (9 de novembro de 2021): 12376. http://dx.doi.org/10.3390/su132212376.
Texto completo da fonteResumo:
For many rock engineering projects, the stress of surrounding rocks is constantly increasing and decreasing during excavating progress and the long-term operation stage. Herein, the triaxial creep behavior of dolomitic limestone subjected to cyclic incremental loading and unloading was probed using an advanced rock mechanics testing system (i.e., MTS815.04). Then, the instantaneous elastic strain, instantaneous plastic strain, visco-elastic strain, and visco-plastic strain components were separated from the total strain curve, and evolutions of these different types of strain with deviatoric stress increment were analyzed. Furthermore, a damage variable considering the proportion of irrecoverable plastic strain to the total strain was introduced, and a new nonlinear multi-element creep model was established by connecting the newly proposed damage viscous body in series with the Hookean substance, St. Venant body, and Kelvin element. The parameters of this new model were analyzed. The findings are listed as follows: (1) When the deviatoric stress is not more than 75% of the compressive strength, only instantaneous deformation, transient creep, and steady-state creep deformation occur, rock deformation is mainly characterized by the instantaneous strain, whereas the irrecoverable instantaneous plastic strain accounts for 38.02–60.27% of the total instantaneous strain; (2) Greater deviatoric stress corresponds to more obvious creep deformation. The visco-elastic strain increases linearly with the increase of deviatoric stress, especially the irrecoverable visco-plastic strain increases exponentially with deviatoric stress increment, and finally leads to accelerated creep and delayed failure of the sample; (3) Based on the experimental data, the proposed nonlinear creep model is verified to describe the full creep stage perfectly, particularly the tertiary creep stage. These results could deepen our understanding of the elasto-visco-plastic deformation behavior of dolomitic limestone and have theoretical and practical significance for the safe excavation and long-term stability of underground rock engineering.
9
Estrada-Royval, Ignacio-Alberto, e Alberto Díaz-Díaz. "Post-curing process and visco-elasto-plastic behavior of two structural adhesives". International Journal of Adhesion and Adhesives 61 (setembro de 2015): 99–111. http://dx.doi.org/10.1016/j.ijadhadh.2015.06.001.
Texto completo da fonte
10
Pipard, Jean Marc, Tudor Balan, Farid Abed-Meraim e Xavier Lemoine. "Physically-Motivated Elasto-Visco-Plastic Model for the Large Strain-Rate Behavior of Steels". Key Engineering Materials 554-557 (junho de 2013): 1164–73. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.1164.
Texto completo da fonteResumo:
A physically based elasto-visco-plastic constitutive model is presented and compared to experimental results for three different mild steels. The experiments consist of tensile tests at strain rates up to 103 s-1 and reverse shear tests. The model requires significantly fewer material parameters compared to other visco-plasticity models from the literature while exhibiting very good accuracy. Accordingly, the parameter identification is simple and intuitive, requiring a relatively small set of experiments. The strain-rate sensitivity modeling is not restricted to a particular hardening law and thus provides a general framework in which advanced hardening equations can be adopted. The model was eventually used as the basis for a homogenization approach at the phase scale; preliminary investigations showed the benefit of such an approach, where microstructure-relevant data can explicitly enter the model and may be used for material design simulations.
Teses / dissertações sobre o assunto "Elasto-Visco-Plastic behavior"
1
Kouah, Mohamed Amine Walid. "Μοdélisatiοn numérique des glissements de terrain : de l’initiatiοn à la transitiοn sοlide-fluide des géοmatériaux. : applicatiοn aux falaises des Vaches Νοires (Νοrmandie, France)". Electronic Thesis or Diss., Normandie, 2024. http://www.theses.fr/2024NORMC004.
Texto completo da fonteResumo:
En Normandie, les falaises des Vaches Noires constituent un secteur original à la morphologie de badlands, affecté par des processus hydrogravitaires (glissements de terrain, coulées de boue, …) emboités dans l’espace et dans le temps. Dans la phase d’initiation, les géomatériaux sont décrits par des lois de comportement élasto- plastique dans le cadre de la mécanique des sols. Toutefois, lorsque ces matériaux perdent leurs propriétés solides après cette initiation et se transforment en un fluide, leur comportement est décrit par la rhéologie des fluides. C'est le cas des coulées de boue argileuses où le comportement initial élasto-plastique des géomatériaux remaniés évolue vers un comportement visqueux sous certaines conditions spécifiques. Ce travail de recherche s’appuyant sur une approche pluridisciplinaire couplant géotechnique et géomorphologie vise à comprendre les comportements hydromécaniques de ces glissements de terrain et de ces coulées de boue dans leur phase d’initiation, à travers une modélisation numérique réalisée avec le logiciel FLAC qui repose sur une approche lagrangienne, utilisant la méthode des différences finies explicites. Par la suite, notre travail se concentre sur la modélisation de la transition solide-fluide du comportement des géomatériaux. Peu de modèles sont capables de prendre en compte à la fois les comportements solide et fluide, ainsi que la transition entre les deux. Nous avons proposé une loi de comportement élasto-viscoplastique, combinant une loi élasto-plastique (Cam-Clay Modifiée) et une loi viscoplastique (Herschel-Bulkley), et intégrant le critère du travail de second ordre locale pour suivre la transition entre les deux comportements. Ce modèle a été implémenté dans le logiciel FLAC. À travers une application concrète, il a été possible de démontrer la faisabilité de ce couplage dans la prise en compte des différents états de ces géomatériauxIn Normandy, the Vaches Noires cliffs present a unique badlands morphology, impacted by hydro-gravitational processes (landslides, mudflows, etc.) which are interrelated in space and time. During the initiation phase, the geomaterials are described by elasto-plastic behavior laws within the framework of soil mechanics. However, once these materials lose their solid properties post-initiation and transform into a fluid state, their behavior is characterized by fluid rheology. This is particularly evident in clayey mudflows where the initial elasto-plastic behavior of the reworked geomaterials transitions towards a viscous behavior under specific conditions. This research work, based on a multidisciplinary approach combining geotechnics and geomorphology, aims to understand the hydromechanical behaviors of these landslides and mudflows in their initiation phase. This is achieved through numerical modeling using the FLAC software, which employs a Lagrangian approach with the explicit finite difference method. Subsequently, our work focuses on modeling the solid-fluid transition of geomaterial behavior. Few models are able to take into account for both solid and fluid behaviors, as well as the transition between the two. We proposed an elasto-viscoplastic behavior law, combining an elasto-plastic law (Modified Cam-Clay) and a viscoplastic law (Herschel-Bulkley), and integrating the criterion of the local second- order work to monitor the transition between the two behaviors. This model was implemented in the FLAC software. Through a specific application, it was possible to demonstrate the feasibility of this coupling in accounting for the different states of these geomaterials
2
Graham, Caroline. "A Finite Element approach to understanding constitutive elasto-plastic, visco-plastic behaviour in lead free micro-electronic BGA structures". Thesis, Heriot-Watt University, 2016. http://hdl.handle.net/10399/3179.
Texto completo da fonteResumo:
This work investigates the non-linear elasto-plastic and visco-plastic behaviour of lead free solder material and soldered joints. Specifically, Finite Element (FE) tools were used to better understand the deformations within Ball Grid Array solder joints (BGA), and numerical and analytical methods were developed to quantify the identified constituent deformations. FE material models were based on the same empirical constitutive models (elastic, plastic and creep) used in analytical calculations. The current work recognises the large number of factors influencing material behaviour which has led to a wide range of published material properties for near eutectic SnAgCu alloys. The work discovered that the deformation within the BGA was more complex than is generally assumed in the literature. It was shown that shear deformation of the solder ball could account for less than 5% of total measured displacement in BGA samples. Shear displacement and rotation of the solder balls relative to the substrate are sensitive to the substrate orthotropic properties and substrate geometry (relative to solder volume and array pattern). The FE modelling was used to derive orthotropic FR4 properties independently using published data. An elastic modulus for Sn3.8Ag0.7Cu was measured using homologous temperatures below 0.3. Suggested values of Abaqus-specific creep parameters m and f (not found in literature) for Sn3.8Ag0.7Cu have been validated with published data. Basic verification against simple analytical calculations has given a better understanding of the components of overall specimen displacement that is normally missing from empirical validation alone. A combined approach of numerical and analytical modelling of BGAs, and mechanical tests, is recommended to harmonise published work, exploit new material data and for more informed analysis of new configurations.
3
Battaini, Michael. "Deformation behaviour and twinning mechanisms of commercially pure titanium alloys". Monash University. Faculty of Engineering. Department of Materials Engineering, 2008. http://arrow.monash.edu.au/hdl/1959.1/61321.
Texto completo da fonteResumo:
The deformation behaviour and twinning mechanisms of commercially pure titanium alloys were investigated using complementary diffraction techniques and crystal plasticity modelling. The main motivation for conducting this investigation was to improve understanding of the deformation of titanium to help achieve the long term aim of reducing manufacturing and design costs. The deformation behaviour was characterised with tension, compression and channel die compression tests for three important variables: orientation; temperature from 25 C to 600 C; and composition for two contrasting alloys, CP-G1 and CP-G4. The experimental data used to characterise the behaviour and determine the mechanisms causing it were: textures determined by X-ray diffraction; twin area fractions for individual modes determined using electron back-scatter diffraction; and lattice strains measured by neutron diffraction. A strong effect of the orientation–stress state conditions on the flow curves (flow stress anisotropy) was found. The propensity for prism hai slip was the dominant cause of the behaviour – samples that were more favourably oriented for prism hai slip had lower flow stresses. Twinning was the most significant secondary deformation mode in the CP-G1 alloy but only had a minor effect on flow stress anisotropy in most cases. In the CP-G4 alloy twinning generally did not play a significant role indicating that hc + ai slip modes were significant in this alloy. Differences in the flow stress anisotropy between the two alloys were found to occur largely in the elasto-plastic transition and initial period of hardening. Modelling results indicated that larger relative resolved shear stress values for secondary deformation modes in the higher purity alloy increased the initial anisotropy. Decreasing flow stresses with increasing temperature were largely caused by a decrease in the critical resolved shear stress (CRSS) values for slip, but also by a decrease in the Hall-Petch parameter for slip. The propagation of twinning was found to be orientation dependent through a Schmid law in a similar way to slip – it was activated at a CRSS and hardened so that an increasing resolved shear stress was required for it to continue operating. The CRSS values determined for the individual twin modes were – 65MPa, 180MPa, 83MPa for {1012}, {1122} and {1011} twinning, respectively. Further, twinning was found to be temperature insensitive except when the ability to nucleate twins posed a significant barrier (for {1011} twinning). Also, the CRSS for {1012} twinning was clearly shown to increase with decreasing alloy purity. A thorough method for determining crystal plasticity modelling parameters based on experimental data was formulated. Additionally, twinning was modelled in a physically realistic manner influenced by the present findings using the visco-plastic self-consistent (VPSC) model. In particular: the activity of twinning decreased in a natural way due to greater difficulty in its operation rather than through an enforced saturation; and hardening or softening due to changes in orientation and dynamic Hall-Petch hardening were important. The rigorous modelling procedure gave great confidence in the key experimental findings.
Capítulos de livros sobre o assunto "Elasto-Visco-Plastic behavior"
1
Kassem, H. A., e G. R. Chehab. "Characterizing the behavior of warm mix asphalt using a visco-elasto-plastic continuum damage model". In Advances in Materials and Pavement Performance Prediction, 101–5. CRC Press, 2018. http://dx.doi.org/10.1201/9780429457791-26.
Texto completo da fonte
2
Semenov, A. S., e B. E. Melnikov. "Multimodel analysis of the elasto-plastic and elasto-visco-plastic deformation processes in materials and structures". In Low Cycle Fatigue and Elasto-Plastic Behaviour of Materials, 659–64. Elsevier, 1998. http://dx.doi.org/10.1016/b978-008043326-4/50110-0.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Elasto-Visco-Plastic behavior"
1
Satou, Yasutaka, Hiroshi Furuya, Kaida Shoko e Tomoyuki Miyashita. "Visco-Elasto-Plastic Behavior of Creased Space Membrane". In AIAA Scitech 2020 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2020. http://dx.doi.org/10.2514/6.2020-1900.
Texto completo da fonte
2
Jacquet, Nicolas, Nicolas Tardif, Thomas Elguedj e Christophe Garnier. "Elasto-Visco-Plastic Buckling of Thick Anisotropic Shells: Numerical Buckling Predictions and Experiments". In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21491.
Texto completo da fonteResumo:
Abstract This work is focused on elasto-visco-plastic (EVP) buckling of thick shell structures. In particular we are interested in predicting accurately the buckling risk of stainless steel components of nuclear fast sodium reactor working under high pressure and at high temperature (around 180 bar and 500 °C). We follow a modeling/experimental approach to solve this problem. The set-up of relevant experiments at such high temperature being complex, we work with a representative material that shows similar EVP and buckling behavior at room temperature. The representative material is an alloy mostly composed of tin, silver and copper, commonly named Sn 3.0 Ag 0.5 Cu. The elasto-visco-plastic constitutive model of the material was first characterized using tensile tests on notched specimen at room temperature under various strain rates, and the model parameters identified using finite element model updating (FEMU). In a second step we performed in plane compressive buckling tests of thick plates for various displacement rates. Surface 3D displacements were acquired using three cameras and digital image correlation. It is well known for thick plates that linearized tangent moduli derived from Levy-Mises flow theory does not give accurate elasto-plastic buckling prediction. Linearized tangent moduli derived from Hencky’s deformation theory gives more accurate buckling prediction for thick plates. This numerical phenomenon known as buckling paradox was well correlated to experiments in the literature. This paradox is applied here to thick plates, with EVP constitutive model, in order to predict buckling. Finally, finite element (FE) modeling of the buckling experiments was performed. Plates are modeled using SHB8PS solid shell elements. Solid shell elements allow direct displacement correlation with experiments and accurate through the thickness behavior with a 3D material model. The numerical modeling includes real plate geometry obtained using post machining measurements, experimental boundary conditions derived from the DIC (Digital Image Correlation) results and the previously identified constitutive material law. Buckling risk is tested at each loading step of the incremental algorithm using the tangent operator derived with the Hencky’s deformation theory. Numerical results show a very good correlation with the experimental results on load and displacement history as well as buckling critical load and buckling mode.
3
Faisal, Hasan M., Zafrul Hakim Khan e Rafiqul Tarefder. "Modeling Nanoscale Rheological and Mechanical Properties of Thin Film Asphalt Binder". In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65531.
Texto completo da fonteResumo:
Traditionally, mechanical properties of asphalt concrete (AC) is evaluated through macro-scale testing. However, when aggregates are mixed with asphalt binder, it creates a thin film of 20μm to 40μm around the aggregate particles and the primary strength of AC is derived from the interaction between the binder and aggregates. Therefore, to understand the behavior of asphalt concrete it is necessary to study the binder properties in a nanoscale. Nanoindentation test has been adopted to examine the thin film material property. In a nanoindentation test, a loaded nanoindenter is used to indent the sample surface and measure the indenter displacement as a function of load. To this day, most researchers have used the Oliver-Pharr method to analyze the indentation test data and obtain Elastic modulus (E) and hardness (H) of the material. Generally, in a nanoindentation test, there is a loading and unloading phase. In an elasto-plastic material, loading phase has elastic and plastic response and unloading phase has only elastic response. In Oliver-Pharr method, elastic modulus is obtained through the slope of the unloading curve. Therefore, Oliver-Pharr method mostly applicable for the elasto-plastic metals because it does not incorporate any viscous effect. However, in case of visco-elastic material like asphalt, during the unloading phase, the slope of the unloading curve becomes negative due to the viscous flow. Therefore, using Oliver-Pharr (OP) method in this circumstances will yield an inaccurate value of modulus of elasticity. In the current study, the test data was modeled and analyzed using a well-established spring-dashpot-rigid (SDR) model for viscoelastic material to determine the elastic, plastic and viscous properties. The model assumes the indenter displacement is a function of a quadratic spring, a quadratic dashpot and a plastic rigid body. The loading phase of the nanoindentation test has three contributing parameters: elasticity (E), indentation viscosity (η) and hardness (H). During creep, only contributing parameter is indentation viscosity (η) and while unloading the contributing factors are found to be E and η. Nonlinear least square curve fitting technique was employed to model the nanoindentation test data to the SDR model to find out the contributing parameters E, η and H. In addition, the extended dwell time on the asphalt binder samples produced positive load displacement curves, which were further analyzed with Oliver-Pharr method. Comparison between two models results show traditional Oliver-Pharr model predicts the material properties 5 to 10 times lower than SDR model, as Oliver-Pharr does not consider the viscous behavior in the material.
4
Diard, O. "A Multi-Scale Approach for Prediction of Irradiation Effect on RPV Steel Toughness". In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71710.
Texto completo da fonteResumo:
Nuclear reactor pressure vessel steels are subjected to an irradiation-induced embrittlement in service and this may lead to a shift of the ductile-to-brittle transition temperature. The prediction of irradiation effect on toughness requires an accurate description of the elasto-visco-plastic behavior of irradiated steels. Recent progresses have been done to describe microstructural evolutions induced by irradiation. Ab-initio computations, molecular dynamics and discrete dislocations dynamics can predict the defects formation and the hardening induced by the dislocations – defects interactions. At this level, the irradiation effect is essentially reported as an increase of the critical resolved shear stress on the crystallographic slip systems. A numerical homogenization method is proposed to predict stress-strain curves of irradiated steels from the computed critical resolved shear stress evolution. Computations of realistic 3D aggregates and classical homogenization are performed with a Finite Element code [1]. Each grain is described as a single crystal with a crystal plasticity law, which naturally introduces the irradiation effect on the slip systems activity. The resulting average response over the whole aggregate corresponds to classical stress-strain curves. A Beremin type local approach is then applied to compute the fracture toughness of irradiated CT specimens. Assuming that the local approach parameters do not depend on the irradiation level, this methodology is able to take benefits of MD and DDD results to predict the irradiation effect on RPV steels toughness.
5
Dongmo, B. F. "A 3D visco-elasto-plasto damage constitutive model of concrete under long-term effects". In AIMETA 2022. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902431-6.
Texto completo da fonteResumo:
Abstract. A comprehensive 3D visco-elasto-plasto-damage constitutive model of concrete is proposed to analyze its behaviour under long-term and cyclic loadings. This model combines the visco-elasticy and plasticity theories together with damage mechanics. The work aims at providing an efficient model capable of predicting the material behaviour, taking into account time-dependent effects at the mesoscale. The visco-elastic part is modeled within the framework of the linear visco-elasticity theory. The creep function is evaluated with the aid of the B3 model by Bažant and Baweja, and implemented via the exponential algorithm. The modified Menétrey-Willam pressure-dependent yield surface, and a non-associated flow rule are used for the plastic formulation of the model. The damage part of the model considers two exponential damage parameters: one in tension, and one in compression, that account for a realistic description of the transition from tensile to compressive failure. After discussing the numerical implementation, the proposed model is calibrated, and numerical results at the mesoscale level are compared to experimental results.