Letteratura scientifica selezionata sul tema "VUMAT user law"
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Articoli di riviste sul tema "VUMAT user law"
1
Hu, Jing, Xiao Xing Li, Kwan Soo Chung e Rao Yao. "Spring-Back Evaluation of Stretch Bending Process Based on Chaboche Combined Isotropic-Kinematic Hardening Laws". Advanced Materials Research 204-210 (febbraio 2011): 1745–50. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.1745.
Testo completoAbstract (sommario):
We present a study on spring-back prediction in the stretching bending process using the Chaboche model combined isotropic-kinematic hardening law and Mises yielding criterion, and a material user subroutine (VUMAT, UMAT) program was developed base on the ABAQUS interface for the model. The effects of different hardening law on the spring-back in the stretch forming process was also analyzed and compared. The simulation results show that the combined isotropic-kinematic hardening law has the better spring-back prediction compared with the pure isotropic and kinematic hardening law in the stretch forming process, which is verified by the experimental results.
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Belova, O. N., D. V. Chapliy e L. V. Stepanova. "APPLICATION OF THE UMAT SUBROUTINE FOR SOLVING CONTINUUM MECHANICS PROBLEMS (OVERVIEW)". Vestnik of Samara University. Natural Science Series 27, n. 3 (8 luglio 2022): 46–73. http://dx.doi.org/10.18287/2541-7525-2021-27-3-46-73.
Testo completoAbstract (sommario):
This paper presents an overview of the application of the UMAT subroutine of the SIMULIA Abaqus multifunctional software package in solid mechanics and related areas. This subroutine is used to describe new user materials that are not available in the class of standard materials of the SIMULIA Abaqus package. This overview article provides examples of problems and constitutive equations of materials that are modeled using UMAT / VUMAT procedures. Various types of materials are presented, successfully described by means of user-defined UMAT and VUMAT procedures. A general description and experience of using the UMAT subroutine is given. The results of finite element modeling of the deformation of aplate weakened by a central circular hole under uniform and uniaxial tension with steady-state creep in a damaged medium evolving according to a power law are presented in the coupled formulation of the problem (creep - damage). The distributions of stresses, strains, and damage fields at the tip of the defect under creep conditions are found, and an analysis is made of the effect of the damage accumulation process on the stress fields at the crack tip under steady-state creep conditions. The distributions of stresses and creep strains are demonstrated taking into account the accumulation of damage over time.
3
Ming, Lu, e Olivier Pantalé. "An efficient and robust VUMAT implementation of elastoplastic constitutive laws in Abaqus/Explicit finite element code". Mechanics & Industry 19, n. 3 (2018): 308. http://dx.doi.org/10.1051/meca/2018021.
Testo completoAbstract (sommario):
This paper describes the development of an efficient and robust numerical algorithm for the implementation of elastoplastic constitutive laws in the commercial non-linear finite element software Abaqus/Explicit through a VUMAT FORTRAN subroutine. In the present paper, while the Abaqus/Explicit uses an explicit time integration scheme, the implicit radial return mapping algorithm is used to compute the plastic strain, the plastic strain rate and the temperature at the end of each increment instead of the widely used forward Euler approach. This more complex process allows us to obtain more precise results with only a slight increase of the total computational time. Corrector term of the radial return scheme is obtained through the implementation of a safe and robust Newton–Raphson algorithm able to converge even when the piecewise defined hardening curve is not derivable everywhere. The complete method of how to implement a user-defined elastoplastic material model using the radial return mapping integration scheme is presented in details with the application to the widely used Johnson–Cook constitutive law. Five benchmark tests including one element tests, necking of a circular bar and 2D and 3D Taylor impact tests show the efficiency and robustness of the proposed algorithm and confirm the improved efficiency in terms of precision, stability and solution CPU time. Finally, three alternative constitutive laws (the TANH, modified TANH and Bäker laws) are presented, implemented through our VUMAT routine and tested.
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Zhao, Pengjing, Jingpin Jiao, Gang Fang, Zhanghua Chen e Xiang Gao. "Investigation on tensile deformation and failure for 5052 aluminum alloy based on continuum damage model". Journal of Physics: Conference Series 2085, n. 1 (1 novembre 2021): 012039. http://dx.doi.org/10.1088/1742-6596/2085/1/012039.
Testo completoAbstract (sommario):
Abstract A VUMAT user material subroutine for the Lemaitre continuous damage mechanics model was developed based on the finite element solver ABAQUS/Explicit platform to investigate the deformation and failure behavior of 5052 aluminum alloy. The mechanical property parameters and damage parameters of 5052 aluminum alloy were identified by the inversion method combining tensile test and finite element simulation. The numerical simulation results showed that the force-displacement curves predicted by the established damage model were in good agreement with the experimental measurement, and the fracture location was close to the experimental results, which verified the accuracy and effectiveness of the damage parameters. The growth and distribution law of damage variable could be intuitively represented by the simulation results by the Lemaitre damage model.
5
Lian, J., M. Sharaf, F. Archie e S. Münstermann. "A hybrid approach for modelling of plasticity and failure behaviour of advanced high-strength steel sheets". International Journal of Damage Mechanics 22, n. 2 (27 marzo 2012): 188–218. http://dx.doi.org/10.1177/1056789512439319.
Testo completoAbstract (sommario):
The ductile damage mechanisms dominating in modern high-strength steels have emphasised the significance of the onset of damage and the subsequent damage evolution in sheet metal forming processes. This paper contributes to the modelling of the plasticity and ductile damage behaviour of a dual-phase steel sheet by proposing a new damage mechanics approach derived from the combination of different types of damage models. It addresses the influence of stress state on the plasticity behaviour and onset of damage of materials, and quantifies the microstructure degradation using a dissipation-energy-based damage evolution law. The model is implemented into ABAQUS/Explicit by means of a user material subroutine (VUMAT) and applied to the subsequent numerical simulations. A hybrid experimental and numerical approach is employed to calibrate the material parameters, and the detailed program is demonstrated. The calibrated parameters and the model are then verified by experiments at different levels, and a good agreement between the experimental and numerical results is achieved.
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Gao, Wei, Zhiqiang Yu, Aijie Ma e Zhangxin Guo. "Numerical simulation of composite grid sandwich structure under low-velocity impact". Science and Engineering of Composite Materials 29, n. 1 (1 gennaio 2022): 516–28. http://dx.doi.org/10.1515/secm-2022-0176.
Testo completoAbstract (sommario):
Abstract The low-velocity impact finite element model of the carbon fiber-reinforced composite grid sandwich structure was established by ABAQUS. Its panels and grid are both carbon fiber-reinforced composite laminates. The constitutive relation of composite laminates is written into the VUMAT user subroutine using the Fortran language. Simulation of intralaminar failure behavior of composite laminates using the three-dimensional Hashin failure criterion. The quadratic stress criterion and the B-K energy criterion were used to simulate the interlaminar failure behavior, and the delamination damage of the composite panel and the interface debonding damage were simulated. The finite element models of four different types of composite grid sandwich structures, including quadrilateral configuration, triangular configuration, mixed configuration, and diamond configuration, were established. The influence of the single grid width and the height of the grid on the impact resistance of each composite grid configuration was studied. Compared with other geometric configurations, triangular grid sandwich structure provides the best energy absorption characteristics, and T-6-10 has the highest fracture absorption energy (15816.46 mJ). The damage propagation law of carbon fiber-reinforced composite grid sandwich structure under impact load is analyzed.
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Bandaru, Aswani Kumar, e Suhail Ahmad. "Effect of Projectile Geometry on the Deformation Behavior of Kevlar Composite Armors Under Ballistic Impact". International Journal of Applied Mechanics 07, n. 03 (giugno 2015): 1550039. http://dx.doi.org/10.1142/s1758825115500398.
Testo completoAbstract (sommario):
A failure model based on the three-dimensional strains in a composite layer with improved progressive damage modeling has been implemented to predict the deformation behavior of composite armors subjected to ballistic impact. The present model comprises mainly of two parts. First, quadratic strain based failure criteria are presented to predict the initiation of failure modes. Second, the post damage softening behavior and degradation of the material stiffness is measured by damage evolution law. The model has been implemented within ABAQUS/Explicit as a user defined subroutine VUMAT. The validity of the model has been carried out by performing computational analysis of different composite armor materials such as Kevlar 29 and Kevlar 129 impacting with cylindrical-hemispherical nosed and 120° conical projectiles. It transpires that the predictions from the present model are in good agreement with the experimental and numerical observations available in the literature in terms of back face signature (BFS) for both the targets and projectiles. Further, the model has been implemented to study the effect of projectile geometry on the velocity time histories of the projectile, residual velocity and ballistic limit velocity. BFS values showed good agreement for conical projectile while for hemispherical projectile it is slightly low. The combination of Kevlar 129 armor and hemispherical projectile shows higher ballistic limit compared to that of the other combinations.
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Al-Azzawi, Ahmad SM, Luiz F. Kawashita e Carol A. Featherston. "Predicting interlaminar damage behaviour of fibre-metal laminates containing adhesive joints under bending loads". Journal of Reinforced Plastics and Composites 41, n. 5-6 (17 novembre 2021): 167–86. http://dx.doi.org/10.1177/07316844211051706.
Testo completoAbstract (sommario):
This study includes experimental and numerical investigations on fibre-metal laminate structures containing adhesive joints under static bending loads. Experimental tests were carried out on Glare® 4B specimens manufactured in-house and containing doubler joint features. Numerical analyses were performed using Abaqus software including damage in the glass fibre reinforced polymer layers, ductile damage in the resin pockets (FM94 epoxy) and plasticity in the metal layers. A new cohesive zone model coupling friction and interfacial shear under through-thickness compressive stress has been developed to simulate delamination initiation and growth at the metal/fibre interfaces with the adhesive joint under flexural loading. This model is implemented through a user-defined VUMAT subroutine in the Abaqus/Explicit software and includes two main approaches, firstly, combining friction and interfacial shear stresses created in the interlaminar layers of the fibre-metal laminate as a result of through-thickness stresses and secondly, considering elastic-plastic damage behaviour using a new cohesive zone model based on the trapezoidal law (which provides more accurate results for the simulation of toughened epoxy matrices than the commonly used bilinear cohesive zone model). Numerical results have been validated against experimental data from 4-point bending tests and a good correlation observed with respect to both crack initiation and evolution. Delamination and shear failure were noted to be the predominant failure modes under bending stresses as expected. This is due to the higher mode-II stresses introduced during bending which cause different damage evolution behaviour to that seen for axial stresses. Finite element results revealed that both friction and shear strength parameters generated from through-thickness compression stresses have a significant effect in predicting damage in fibre-metal laminate structures under this type of loading.
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Chaouki, Hicham, Stéphane Thibodeau, Mario Fafard, Donald Ziegler e Houshang Alamdari. "Characterization of the Hot Anode Paste Compaction Process: A Computational and Experimental Study". Materials 12, n. 5 (8 marzo 2019): 800. http://dx.doi.org/10.3390/ma12050800.
Testo completoAbstract (sommario):
The aim of this work is to model and characterize green anode paste compaction behavior. For this purpose, a nonlinear viscoplastic constitutive law for compressible materials, based on the finite strain theory and the thermodynamic framework, was used. An experimental study was carried out to characterize axial and radial behaviors of the anode paste. To this end, simple compaction tests using a thin steel instrumented mold were performed at a temperature of 150 °C. Results of these experiments brought out the nonlinear mechanical behavior of the anode paste. Furthermore, they showed the importance of its radial behavior. The constitutive law was implemented in Abaqus software through the user’s material subroutine VUMAT for explicit dynamic analysis. An inverse analysis procedure for material parameters identification showed that the model predicts compaction tests results with a good agreement. In order to assess the constitutive law predictive potential in situations involving density gradients, compaction tests using complex geometries such as slots and stub holes were carried out. Finite element simulation results showed the ability of the model to successfully predict density profiles measured by the X-ray tomography.
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Zhang, Yanfeng, Zhengong Zhou e Zhiyong Tan. "Compression Shear Properties of Bonded–Bolted Hybrid Single-Lap Joints of C/C Composites at High Temperature". Applied Sciences 10, n. 3 (5 febbraio 2020): 1054. http://dx.doi.org/10.3390/app10031054.
Testo completoAbstract (sommario):
Based on previous research, in this paper, the compressive shear failure behavior and mechanical properties of bonded–bolted hybrid single-lap joints of C/C composites at high temperature were studied. The compression shear test was performed on the joints at 800 °C to obtain the load–displacement curve and failure morphology. The failure modes of joints were observed by digital microscopy and scanning electron microscopy. A numerical analysis model was implemented in finite element code Abaqus/Explicit embedded with the user material subroutine (VUMAT). The numerical results were compared with the test results to verify the correctness of the model. The interrelationship of the compression shear loading mechanism and the variations in stress distribution between bonded joints and bonded–bolted hybrid joints at high temperature were explored. The progressive damage of hybrid joints and the variations in the ratio of the bolt load to the total load with displacement were obtained.
Tesi sul tema "VUMAT user law"
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Gouillou, Franck. "Comportement dynamique des composites à fibres naturelles et résines thermoplastiques : étude de la sensibilité à la vitesse de déformation". Electronic Thesis or Diss., Ecole nationale des Mines d'Albi-Carmaux, 2024. http://www.theses.fr/2024EMAC0004.
Testo completoAbstract (sommario):
Ces travaux visent à explorer le comportement des composites à matrice thermoplastique renforcée de fibres naturelles en examinant leur réponse à la vitesse de déformation lors de sollicitations en traction, en se concentrant particulièrement sur la variation du module d'élasticité longitudinal pour les composites à 0° et du module d'élasticité en cisaillement pour les stratifiés à ±45°. En utilisant des fibres de bambou, de lin et de basalte comme renforts unidirectionnels et le polyamide-11 semi-cristallin ainsi que la résine amorphe ELIUM comme matrices, diverses campagnes expérimentales ont été menées pour caractériser les matériaux. Des tests de traction statiques et dynamiques sont effectués à l'aide d'équipements électromécaniques, DMA et tours de chute. De nombreuses simulations numériques explicites sont utilisées afin d'analyser les données expérimentales. Les résultats révèlent que les composites avec des plis à 0° montrent une sensibilité limitée aux vitesses de déformation inférieurs à 100 s-1, les composites en bambou et en lin présentant peu de variations du module de Young, tandis que les composites renforcés de basalte montrent une légère augmentation. Cependant, les composites avec un empilement à ±45° affichent une sensibilité accrue, principalement influencée par la résine. Cette investigation exhaustive fournit des informations sur le comportement de ces composites à fibres naturelles et polymères thermoplastiques sous différentes vitesses de chargement, guidant leur optimisation et applicationThese works aim to explore the behavior of thermoplastic matrix composites reinforced with natural fibers by examining their strain rate response under tensile loading, focusing particularly on the variation of the longitudinal elastic modulus for 0° composites and the shear modulus for ±45° laminates. Using bamboo, flax, and basalt fibers as unidirectional reinforcements and semi-crystalline polyamide-11 as well as amorphous ELIUM resin as matrices, various experimental campaigns were conducted to characterize the materials. Static and dynamic tensile tests were performed using electromechanical equipment, DMA, and drop towers. Numerous explicit numerical simulations were employed to analyze the experimental data. The results reveal that 0° plies exhibit limited sensitivity to strain rates below 100 s⁻¹, with bamboo and flax composites showing little variation in Young's modulus, while basalt-reinforced composites display a slight increase. However, composites with ±45° stacking exhibit increased sensitivity, primarily influenced by the resin. This comprehensive investigation provides insights into the behavior of these natural fiber-reinforced thermoplastic polymer composites under different loading rates, guiding their optimization and application
Atti di convegni sul tema "VUMAT user law"
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Mokhtari, Mojtaba, Ekaterina Kim e Jørgen Amdahl. "Numerical Simulation of an Aluminium Panel Subject to Ice Impact Load Using a Rate and Pressure Dependent Elastoplastic Material Model for Ice". In ASME 2023 42nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/omae2023-104771.
Testo completoAbstract (sommario):
Abstract This study presents an elastoplastic material model with a pressure and rate dependent yield criterion for freshwater polycrystalline ice, implemented to simulate the structural damage in a full-scale AA5083-H116 aluminium panel subject to ice impact load in a drop test. The proposed ice material model is validated against physical ice-crushing tests with a good correlation between the experimental and numerical results. The material model is based on the Tsai-Wu yield surface, which is defined to evolve differently in the ductile and brittle regimes of ice to account for the ‘ductile-to-brittle transition’. The relationships between ice strength and strain rate in the constitutive laws are obtained from the literature. The constitutive laws are written in Fortran as vectorised user material (VUMAT) for the Abaqus Explicit solver. The mechanical behaviour of AA5083-H116 alloy is simulated using the Johnson-Cook plasticity model. The numerical simulation of the ice drop test on the stiffened aluminium panel produced excellent agreements with the experimental data using the proposed material model for ice and the Johnson-Cook model for AA5083-H116 alloy.
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Patel, Shivdayal, e Suhail Ahmad. "Failure Prediction of Fiber Reinforced Laminated Composite Plates Under Low Velocity Impact". In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54486.
Testo completoAbstract (sommario):
The low velocity impact on composites has been studied as it leads to serious damage. The damage initiates as an intra ply matrix crack due to shear or bending which propagates further into the interface causing de-lamination between dissimilar plies and fiber breakage. This damage evolves with time and adversely affects the mechanical properties and strength of the composite. Since, multiple cracks in the ply are difficult to track, a progressive damage mechanics approach is used to model this failure. The inter ply failure is modeled using cohesive surfaces between the plies. The low velocity impact on composite plate is studied using finite element method. Impact parameters like velocity of impactor, the mass of the impactor and elastic properties of the material etc. are considered. An explicit central difference integration scheme is used to solve for displacements and impact forces. Progressive damage and failure in composites is modeled; an efficient algorithm has been developed and implemented in the FE code ABAQUS through a user-defined subroutine (VUMAT). Reduced integration yields satisfactory results for the impactor velocity less than or equal to 3 m/s for larger mass impact. However, full integration is recommended to obtain the satisfactory results for the (impactor velocity beyond 3 m/s), high velocity impact involving small masses. For the low velocity impact, the peak contact force and displacement are linear functions of impactor velocity for a constant mass. However, a nonlinear behavior is observed for the variation of mass with a constant striking velocity.
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Wenman, Mark, James Barton, Kenneth Trethewey, Sean Jarman e Paul Chard-Tuckey. "Finite Element Modelling of Transgranular Chloride Stress Corrosion Cracking in 304L Austenitic Stainless Steel". In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61262.
Testo completoAbstract (sommario):
Austenitic stainless steels (ASS) have excellent resistance to general corrosion. However, these steels can be susceptible to localised corrosion such as pitting and crevice corrosion. In the presence of a tensile stress they can also exhibit stress corrosion cracking (SCC). In pressurised water reactor (PWR) nuclear plant incidents of SCC, especially chloride-induced SCC (CISCC), have been observed. Chloride ions which can lead to CiSCC of even low carbon austenitic grades can be introduced from many sources including the atmosphere and materials introduced into the reactor environment. Stress can result from primary loading or introduced as secondary stresses, such as residual stress, through machining or welding processes. Residual stresses are internal self-balancing stresses that can act alone or together with a primary stress to cause premature failure of a component. 15 mm lengths of 304L ASS tube were subjected to an in-plane compression of between 1–10 mm before unloading. This created regions of plasticity and on relaxation the specimen contains a complex state of residual stresses that can be modelled by finite element (FE) methods. The tube specimens were then boiled in MgCl2 for 14 days before metallographic examination. A FE model of transgranular CISCC has been created by writing a VUMAT user subroutine implemented into the commercial FE code ABAQUS. The model is based on simple rules which include the initiation of surface corrosion pits from which, under mechanical control, SCC cracks may propagate. The model includes rules for SCC growth, based on hydrostatic stress state, and can incorporate the idea of grain orientation effects. Cracks created interact with and modify the residual stress field in the tube. Test results were then compared with model outputs. Crack morphologies and to a certain extent crack positions matched well with experiment. Attempts were made to calculate the crack tip driving forces from the model. The results also highlight the need to consider the importance of triaxial stress states, created by pits and cracks, and stress as a tensor rather than a scalar property. The effect of grain misorientation is also investigated, but so far, found to be of more limited importance for modelling transgranular CISCC.