Article
Chemistry, Multidisciplinary
Damin Lu, Keshi Zhang, Guijuan Hu
Summary: The study reveals that pre-cyclic deformation significantly influences the plastic flow behavior of FCC polycrystalline aluminum, with subsequent yield surface shape and plastic flow direction depending on offset strain levels and re-loading paths. The deviation angle between plastic flow direction and theoretical orthogonal direction is significant in the inverse pre-straining direction, but negligible in the pre-straining direction.
Article
Materials Science, Multidisciplinary
Cathy Bing, Thomas R. Bieler, Philip Eisenlohr
Summary: Plastic deformation behavior is often assessed by characterizing the surface, but it is uncertain if surface observations can be representative of bulk properties. In this study, crystal plasticity simulations were used to investigate the effect of depth on slip family activity in polycrystalline metals. It was found that there can be a deviation from bulk slip activity near the surface, depending on the slip system and depth.
Article
Materials Science, Multidisciplinary
Yoshiki Kawano, Tsuyoshi Mayama, Masatoshi Mitsuhara, Shigeto Yamasaki, Michihiro Sato
Summary: This study extended the slip operation factor (SOF) to adapt to individual slip systems and considered the contribution of secondary slip systems, resulting in the development of the generalized SOF (SOFS) and the modified version (MSOF). Experimental results showed that SOFS provided similar results to slip strain distributions for individual slip systems when single slips were dominant and the deformation was slight, while MSOF predicted strain distributions with higher accuracy compared to SOF.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Engineering, Mechanical
Tomohiro Toyoda, Ryo Yasuike, Toshihiro Noda
Summary: In this study, a elasto-plastic constitutive model of friction incorporating the concept of superloading surface was developed based on the subloading friction model. The proposed model achieves a smooth transition of friction by describing the evolution rule of structure, treating the state with static friction coefficient larger than kinetic friction coefficient as the bulkiness of structure. The positive definiteness of the plastic multiplier, loading condition, and material parameters were derived, and the validity of the proposed model in accordance with the subloading-friction model was confirmed through a stick-slip simulation of a mass-spring system.
TRIBOLOGY INTERNATIONAL
(2024)
Article
Computer Science, Interdisciplinary Applications
G. T. Houlsby, I. A. Richards
Summary: We develop a series of models of the bounding surface type within the context of hyperplasticity theory, in which models are completely defined by the specification of two potentials. We first describe a simple bounding surface type model, based on an equivalent multi-surface model, but with the advantages that (a) only a single yield surface is required and (b) a smooth rather than piecewise linear response is achieved. We then generalise this model in a way that allows it to be calibrated against real data with similar facility to a multi-surface model. Each model is presented in a simple one dimensional form, with generalisations to two dimensions and to a full tensorial form. Finally we give an example of the newly developed model calibrated against a monotonic test, and present comparisons with one-way and two way cycling and two complex bi-directional tests.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Chemistry, Multidisciplinary
Jianting Li, Jiaquan Li, Hongji Liu, Li Zhang, Yang Lu, Zhengzheng Zhou
Summary: This study discovered that three polymorphs of isonicotinamide exhibited one-dimensional plasticity, and the disparity of intermolecular interactions played a crucial role in determining the plastic properties of the crystals. The findings suggest the importance of plasticity in pharmaceuticals and material sciences.
CHINESE CHEMICAL LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Joseph Indeck, David Cereceda, Jason R. Mayeur, Kavan Hazeli
Summary: The use of machine learning techniques in mechanics and materials research can enhance the understanding of microstructure-property relationships. In this study, various machine learning techniques were employed to analyze mesoscopic deformation mechanisms and gain insights into void nucleation in polycrystalline metals. The results showed that unsupervised clustering analysis combined with a K-nearest neighbor classifier accurately characterized slip transmission and identified grains with fatigue-induced voids. It was also discovered that the inclusion of partially-active slip systems was more appropriate for predicting slip activity than the binary classification. The study concluded that grains containing fatigue-induced voids were more likely to be surrounded by grains with orientations that inhibited slip transmission according to the Lee Robertson-Birnbaum criteria. Furthermore, it was demonstrated that smaller datasets using limited simulation results could yield similar outcomes when additional physical descriptors for the slip system activity were incorporated.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Mechanics
K. Somlo, B. H. Frodal, C. V. Funch, K. Poulios, G. Winther, O. S. Hopperstad, T. Borvik, C. F. Niordson
Summary: The mechanical anisotropy created by additive manufacturing (AM) is investigated through crystal plasticity simulations, using periodic representative volume elements specific to each material and calibrated against tensile tests.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Engineering, Mechanical
Dylan Agius, Anna Kareer, Abdullah Al Mamun, Christopher Truman, David M. Collins, Mahmoud Mostafavi, David Knowles
Summary: This study incorporates length scale dependence into classical crystal plasticity simulations to ensure a more accurate representation of meso-scale and macro-scale deformation. By adjusting the critical resolved shear stress and slip transfer between grains, the micro-mechanisms near the grain boundaries are effectively incorporated into the simulations, enhancing the predictions of local deformation.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Chemistry, Physical
Mingliang Men, Bao Meng
Summary: This study investigated the influence of grain orientation and grain size distribution on the evolution of yield loci in SUS304 stainless steel foils. The results showed that there is an interaction between grain size distribution and texture, and the impact of the size effect on the shape of yield loci is weaker when the grain size distribution is more uniform.
Article
Mechanics
Vinayak, Smriti, Ajeet Kumar
Summary: This work presents a formulation for the elastoplastic deformation of a rod's cross-section, which takes into account both the three-dimensional stored energy density model and a rate-independent phenomenological plasticity model. By imposing a uniform strain field along the rod's arc-length, the nonlinear elastoplastic rod problem can be reduced to the cross-sectional problem. A three-dimensional elastoplastic moduli tensor and a return map algorithm are derived to solve the deformation problem of the cross-section. The results show that off-axis anisotropy during plasticity can lead to unusual out-of-plane warping and coupling between different modes. The elastoplastic stiffness of the rod is not only dependent on the strain state but also on the direction of strain rate.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Ronan Madec, Luc Portelette, Bruno Michel, Jonathan Amodeo
Summary: The mechanical behavior of UO2 single crystal, especially the unexpected multi-slip observations, has been studied in this research. A multi-scale model based on composite slip is proposed, in which dislocation density can be transferred from primary slip systems to secondary systems under the effect of cross-slip. This approach accurately describes the anisotropic mechanical response of UO2 single crystal, providing new insights into the links between dislocation microstructures and mechanical properties. The composite slip mechanism appears to be a candidate for explaining unexpected plastic behaviors in complex materials with multiple slip modes, suggesting that slip activation may be more complex than in usual constitutive laws.
Article
Mechanics
Oguz Umut Salman, Ioan R. Ionescu
Summary: Recent experiments have shown that the mechanical response of crystals is highly sensitive to quenched disorder in the sample and the crystal orientation. Numerical and theoretical studies on clean crystal pillars suggest that depending on the crystal orientation, a single glide plane or multiple glide planes can be activated, leading to either localized deformation or more uniform deformation. Strain localization can be avoided by introducing inhomogeneities inside the crystal or altering the crystal orientation to activate multiple slip systems.
MECHANICS RESEARCH COMMUNICATIONS
(2021)
Article
Engineering, Multidisciplinary
Mian Xiao, WaiChing Sun
Summary: This paper introduces a new elastoplasticity model which utilizes deep geometric learning to reconstruct the yield surface based on a set of data points in a parametric space. The use of coordinate charts and local parametrization provides advantages in terms of accuracy and feasibility.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Manufacturing
Mitsutoshi Kuroda
Summary: This article describes the fundamentals and importance of the yield surface vertex effects in plastic flow localization predictions. The theoretical significance, experimental evidence, and modeling strategies of the yield surface vertices are presented. Previous studies on plastic flow localization analyses incorporating the yield surface vertex effects are reviewed. The article also highlights the limitations of conventional plasticity theories in predicting shear bands and discusses recent developments in gradient-enhanced vertex-type plasticity and crystal plasticity theories.
INTERNATIONAL JOURNAL OF MATERIAL FORMING
(2022)
Article
Engineering, Mechanical
Jisheng Qin, Bjorn Holmedal, Odd Sture Hopperstad
INTERNATIONAL JOURNAL OF PLASTICITY
(2018)
Article
Nanoscience & Nanotechnology
Kai Zhang, Knut Marthinsen, Bjorn Holmedal, Trond Aukrust, Antonio Segatori
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2018)
Article
Engineering, Mechanical
Jisheng Qin, Bjorn Holmedal, Odd Sture Hopperstad
INTERNATIONAL JOURNAL OF PLASTICITY
(2019)
Article
Engineering, Mechanical
K. Zhang, B. Holmedal, T. Manik, A. Saai
INTERNATIONAL JOURNAL OF PLASTICITY
(2019)
Article
Engineering, Mechanical
Bjorn Holmedal
INTERNATIONAL JOURNAL OF PLASTICITY
(2019)
Article
Materials Science, Multidisciplinary
Siri Marthe Arbo, Tina Bergh, Bjorn Holmedal, Per Erik Vullum, Ida Westermann
Article
Multidisciplinary Sciences
Emil Christiansen, Calin Daniel Marioara, Bjorn Holmedal, Odd Sture Hopperstad, Randi Holmestad
SCIENTIFIC REPORTS
(2019)
Article
Materials Science, Multidisciplinary
Eva Anne Mortsell, Ida Westermann, Calin Daniel Marioara, Ketill Olav Pedersen, Sigmund Jarle Andersen, Jostein Royset, Bjorn Holmedal, Randi Holmestad
Article
Materials Science, Multidisciplinary
Bjorn Holmedal
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2020)
Article
Engineering, Multidisciplinary
T. Manik, H. M. Asadkandi, B. Holmedal
Summary: A new stable return-mapping algorithm is proposed for crystal-plasticity solutions, which uses a regularized yield surface with very large exponents. The algorithm achieves good numerical stability and is implemented as a fast and stable implicit method in finite element software for simulations of both single crystals and polycrystalline materials.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Sohail Shah, Akash Gopal, Elisabeth Thronsen, Constantinos Hatzoglou, Bjorn Holmedal
Summary: Comparison between natural and artificial ageing treatments with cyclic deformation ageing at room temperature revealed different fracture behaviors and mechanical responses for Al-Zn-Mg alloys. Cyclic ageing resulted in early slant shear fracture, while natural ageing improved mechanical properties.
MATERIALS & DESIGN
(2022)
Article
Nanoscience & Nanotechnology
Jianbin Xu, Lei Liu, Odd Sture Hopperstad, Bjorn Holmedal, Tomas Manik, Knut Marthinsen
Summary: In this study, a novel method is proposed to quantitatively analyze localized deformation bands exhibiting the Portevin-Le Chatelier effect. The method introduces a multi-strain-jump function to capture the experimentally obtained strain profile. The approach allows for automatic extraction of band strain and enables the linking of band characteristics with local material properties.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Christoph M. Hell, Bjorn Holmedal, Ruben Bjorge, Calin D. Marioara, Randi Holmestad
Summary: In this study, the origin of a double-peak during artificial aging of an EN-AW 6082 is analyzed using (S)TEM. The TEM data is used in a strength model to explore the origin and broader strength plateau of the double-peak. It is concluded that the first peak is caused by wide and high-density p-type precipitates, while the second peak is due to a broader size distribution of precipitates of the same type. The second peak is maintained by long precipitates of a hybrid type with overaged phases, counteracting the strength loss from Ostwald ripening.
Article
Materials Science, Multidisciplinary
E. Thronsen, S. Shah, C. Hatzoglou, C. D. Marioara, S. Wenner, S. J. Andersen, B. Holmedal, R. Holmestad
Summary: The evolution of early-stage precipitates in a 7003 aluminium alloy was investigated through artificial ageing. It was found that after 10 minutes of artificial ageing, the hardness of the precipitates decreased and their size increased, indicating the dissolution of the Guinier-Preston (GP) zones. Subsequently, as the ageing time increased, the hardness gradually increased and new precipitate phases appeared. Atomically resolved scanning transmission electron microscopy images of the disputed T' phase were also presented.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)