Article
Engineering, Mechanical
Zhanming Shi, Jiangteng Li, Mengxiang Wang, Han Tan, Hang Lin, Kaihui Li
Summary: This study investigates the influence of temperature on the fracture behavior and morphology of granite after thermal shock. The results show that temperature can change the fracture mode of rocks and have a softening effect on rocks. High temperatures can convert rocks from brittle to ductile failure and even change the fracture mode from pure mode III to mixed mode I/III fracture.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Yuanfeng Jiang, Zheming Zhu, Liyuan Yu, Lei Zhou, Renfan Zhang, Leijun Ma
Summary: This study investigates the influence of high temperature on the fracture behavior of hard and soft rocks. It is found that high temperature significantly affects the mineral composition of rocks and reduces the fracture toughness of granite and sandstone, leading to obvious plastic failure features.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Mechanics
Junjie Zhou, Yanxi Chen, Huawei Feng, Huihan Chen, Xingzhe Yu, Bin Liu
Summary: Obtaining intergranular and transgranular fractures through grain boundary engineering is an efficient technique to improve the effective fracture toughness of polycrystalline aggregates. The crack paths of different microstructures and the effect of grain aspect ratio on fracture toughness are analyzed. The results show that the effective fracture toughness can be increased by enlarging the aspect ratio of the grains but is still limited to the grain fracture toughness. This study provides valuable guidance for designing microstructures and improving fracture toughness in materials.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Geological
Peiwang Cao, Tao Zhou, Jianbo Zhu
Summary: This study investigates the rate dependent behavior of mixed mode I/II fracture toughness in rock. Split Hopkinson pressure bar tests were performed on cracked sandstone specimens with different loading angles and strain rates. The results show that the peak load and peak strain increase with increasing strain rates while the influence of loading angle is almost negligible. Dynamic mode I and mode II stress intensity factors as well as effective fracture toughness increase rapidly with increasing strain rate before reaching a plateau. The findings of this study contribute to a better understanding of the rate effect of mixed mode I/II fracture and its micromechanism.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Mechanics
Claudio Ruggieri, Andrey P. Jivkov
Summary: This study introduces a probabilistic framework incorporating measured statistics of microcracks to predict the cleavage fracture toughness distribution in structural ferritic steels. Experimental Jc-distribution data was obtained through fracture toughness testing on a 22NiMoCr37 pressure vessel steel under varying temperatures. Metallographic examination revealed the distribution of carbides, assumed as Griffith fracture-initiating particles, to predict the cleavage fracture toughness distribution.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Mechanics
Chuanju Liu, Qianjun Zhang, Qiang Zhu, Hongwei Deng
Summary: This study examines the dynamic fracture toughness of freeze-thawed granite. Freeze-thaw cycles are applied to treat granite samples, and the microstructure changes are measured using a nuclear magnetic resonance testing system. Dynamic testing with split Hopkinson pressure bar equipment is conducted to obtain the dynamic fracture toughness. Additionally, fractal geometry is used to analyze the roughness of the rock fracture surface and define FT damage. Based on these findings, a prediction model for dynamic fracture toughness is proposed, and the influence of F-T cycles and loading rate on fracture toughness is discussed.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Construction & Building Technology
Songbo Ren, Gu Song, Kong Chao, Shenghui Zeng, Gu Ying, Li Gang, Yang Tao, Liqiong Yang
Summary: In this study, the effects of morphological characteristics on fracture behaviors of corroded steel were analyzed. The results showed that the fractal dimension of critical corrosion pit was a key factor influencing the mechanical property and fracture behavior. Additionally, the oxide passivation layer was found to have an impact on the fracture toughness properties of corroded steel.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Engineering, Mechanical
Wenrui Wang, Guangqing Zhang, Hu Cao, Lei Chen, Chunyang Zhao
Summary: Alternate fracturing is a more effective method for increasing natural gas production, as it can form complex fracture networks and control fracture geometry more efficiently. The critical factors affecting the generation of branch fractures are the fracture spacing and the number of main fractures.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Environmental Sciences
Shengyang Feng, Yurong Wu, Yong Liu, Xiangyang Li, Xiaodong Wang, Puxin Chen
Summary: A novel model combining fractal theory and DFN is proposed to simulate radon migration, revealing the impact of different parameters on radon migration. Fractal dimension of fracture lengths and dip angle are identified as key factors influencing radon migration.
Review
Chemistry, Physical
Haitang Huang, Guifa Li, Xuan Xiao, Shiqiang Lu, Ping Peng
Summary: Based on first-principle calculations, the micromechanism in fracture toughness of the NbCr2 Laves phase improved by Nickel alloying was estimated. It was found that the Nb8Cr15Ni phase exhibited improved mechanical performance and optimal fracture toughness mainly due to strengthening of metal bonds and weakening of covalent bonds. These findings open up a potential avenue for comprehensive study of NbCr2 Laves materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Magnus Boasen, Carl F. O. Dahlberg, Pal Efsing, Jonas Faleskog
Summary: A multiple mechanism weakest link model for brittle fracture was developed based on experimental observations and micro mechanical analysis, which accurately predicted the fracture characteristics.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Engineering, Mechanical
Yehui Cui, Xiangguo Zeng, Vincent B. C. Tan, Zhilang Zhang
Summary: In this study, the dynamic fracture performances of NiTi alloy were comprehensively investigated through experiments and simulations. The fracture behavior was found to exhibit quasi-brittle features. A novel constitutive model was proposed to accurately reproduce the crack propagation process. Additionally, it was demonstrated that a smaller grain size could improve the intergranular fracture toughness.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Materials Science, Ceramics
Jingyao Dai, Evan J. Pineda, Brett A. Bednarcyk, Jogender Singh, Namiko Yamamoto
Summary: Micromechanics modeling was used to study the effects of weak interphases and thermal residual stress on the mechanical responses and fracture behaviors of B4C-TiB2 composites. Higher TiB2 volume fractions were found to enhance micro-cracking, while variations in TiB2 particle sizes had limited effect on micro-cracking behaviors.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Engineering, Chemical
Xiaoli Xu, Liqi Xu, Changqi Yue, Guannan Liu
Summary: This paper establishes a fractal permeability model considering the microstructure of coal seam fractures, and analyzes the influence of microscopic fracture structures on equivalent permeability.
Article
Energy & Fuels
Yu Zhao, Chaolin Wang, Lin Ning, Houfa Zhao, Jing Bi
Summary: This paper conducted triaxial compression tests on coal samples using a nuclear magnetic resonance (NMR) testing system, investigated the development of pores and fractures in coal under stress conditions, proposed a new method for estimating crack-initiation stresses, and analyzed the fractal dimensions of pores.
Article
Materials Science, Ceramics
Daniel Drdlik, Dominik Zeman, Pavel Tofel, Zdenek Chlup, Hynek Hadraba, Katarina Drdlikova
Summary: The study investigates the correlation of different piezoelectric measurement methods on various material states, finding that ceramic powder treatment by ball milling and EPD technique can lead to thick and dense deposits. The results show that after sintering, BCZT ceramics can achieve high relative density, hardness, and piezoelectric coefficients.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Ceramics
Gianmarco Taveri, Ondrej Hanzel, Jaroslav Sedlacek, Jaromir Tousek, Zuzana Nescakova, Martin Michalek, Ivo Dlouhy, Miroslav Hnatko
Summary: A new procedure was developed to consolidate Bioglass(R) 45S5 powder in water-based solutions, resulting in nearly fully dense samples with hydroxyapatite formation observed in simulated body fluid immersion. Analysis of microstructure and chemistry differences between the base material and dissolution product suggest potential applications of the densified Bioglass(R) in bio-engineering.
CERAMICS INTERNATIONAL
(2021)
Article
Materials Science, Ceramics
Monika Tatarkova, Peter Tatarko, Alexandra Kovalcikova, Ivo Dlouhy, Jan Dusza, Pavol Sajgalik
Summary: The addition of h-BN nanosheets during spark plasma sintering process improved the fracture toughness and strength of Si3N4, while slowing down the alpha -> beta phase transformation. Proper control of the particle size and content of h-BN nanosheets can effectively enhance the mechanical properties of Si3N4.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Multidisciplinary
Igor Moravcik, Naeimeh Sadat Peighambardoust, Amir Motallebzadeh, Larissa Moravcikova-Gouvea, Chang Liu, J. Manoj Prabhakar, Ivo Dlouhy, Zhiming Li
Summary: The nitrogen-alloyed variant of the CoCrNi MEA exhibits higher corrosion resistance, while both nitrogen-free and nitrogen-doped MEAs show lower corrosion current and rates compared to 316L steel. The addition of nitrogen significantly improves the pitting corrosion resistance of CoCrNiN.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Jakub Veverka, Monika Vilemova, Zdenek Chlup, Hynek Hadraba, Frantisek Lukac, Stefan Csaki, Jirf Matejicek, Jirina Vontorova, Tomas Chraska
Summary: The study investigates the preparation of pure tungsten samples using Field Assisted Sintering, and significant improvement in mechanical performance has been achieved for short dwell times (2 min) and vacuum or Ar + H2 atmosphere.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Luca Bertolla, Ivo Sulak, Jiri Bursik, Ivo Dlouhy, Jiri Smilek, Petra Macova, Jiri Holas
Summary: In this study, hexagonal boron nitride (h-BN) was successfully exfoliated into nanosheets using concentrated low-modulus water glass, resulting in a yield of nearly 30% BNNSs. The BNNSs obtained had lateral sizes of approximately 250 nm and narrow size distribution, aligning into parallel rows. High-resolution transmission electron microscopy (HR-TEM) analysis confirmed the integrity of exfoliated BNNSs preserved by water glass, leading to a high amount of undamaged structure BNNSs.
Article
Engineering, Mechanical
Martin Monik, Selina Delgado-Raack, Hynek Hadraba, David Jech, Roberto Risch
Summary: During recent European prehistory, slightly retrograded rocks were used to manufacture edge-ground tools in two different supply systems. Research found that in the Neolithic Central Europe, amphibolic hornfels was one of the most widely used and high-quality rocks, but it was not superior in quality on a broader European scale and was surpassed by Iberian gabbros. The long-distance transport of amphibolic hornfels was only partially explained by its mechanical qualities, suggesting a well-functioning social and economic network established over large parts of Central Europe.
Article
Materials Science, Multidisciplinary
Igor Moravcik, Martin Zeleny, Antonin Dlouhy, Hynek Hadraba, Larissa Moravcikova-Gouvea, Pavel Papez, Ondrej Fikar, Ivo Dlouhy, Dierk Raabe, Zhiming Li
Summary: This study investigates the effects of interstitial nitrogen and carbon on the stacking fault energy (SFE) of an equiatomic Cobalt-Chromium-Nickel (CoCrNi) medium entropy alloy. The results show that both nitrogen and carbon in solid solution increase the SFE of the alloy, with nitrogen having a more significant effect. Additionally, the SFE of CoCrNi increases after doping with 0.5 atomic percent of interstitial nitrogen.
SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Hynek Hadraba, Zdenek Chlup, Jan Cizek, Ivo Kubena
Summary: This study designed ferritic-martensitic 9Cr-1W Eurofer steels with homogeneous dispersion of nitrides, and the strength of these NDS steels was comparable or higher than that of conventional and ODS variants. The NDS steels exhibited similar uniform plastic strain behavior to ODS steels, and the BN reinforcement effectively prevented plastic deformation at high temperatures, potentially leading to the development of heat-resistant low-chromium 9Cr-1W steels.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Filip Siska, Hynek Hadraba, Ludek Stratil, Stanislava Fintova, Ivo Kubena
Summary: The effect of grain orientation on the mechanical behavior of the 14Cr ODS steel was investigated. The study found that both grain orientations provide similar strengthening up to 600℃, while the orientation parallel to the extrusion direction provides higher strength at temperatures 700-800℃.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Hector A. Tinoco, Stanislava Fintova, Irma Heikkila, Diego Herrero, Taina Vuoristo, Ivo Dlouhy, Pavel Hutar
Summary: This study focused on characterizing three variants of microalloyed 38MnSiV6 steel in terms of microstructure, mechanical properties, and crack initiation. It was found that non-metallic inclusions in the steel had an impact on the mechanical properties, with MnS and MnSeS inclusions being responsible for strain localization and crack initiation.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Ferdinand Dobes, Hynek Hadraba, Zdenek Chlup, Jiri Matejicek
Summary: By conducting compressive creep tests, it was found that the presence of aluminum nitride particles does not significantly affect the creep rate, while the presence of oxide particles reduces the creep rate. Boron nitride particles have no influence on the creep rate at low stresses but reduce it substantially at high stresses.
Article
Materials Science, Multidisciplinary
Zoya Hadzhieva, Katarzyna Cholewa-Kowalska, Ivo Dlouhy, Tomasz Moskalewicz, Aldo R. Boccaccini
Summary: Coatings based on zein with the addition of bioactive glass particles doped with fluoride or a combination of fluoride and copper were deposited on titanium by electrophoretic deposition. The coatings showed improved scratch resistance and antibacterial activity, with no impact on bioactivity. These coatings have potential applications in orthopaedic and dental implants.
Proceedings Paper
Engineering, Mechanical
Peter Jurci, Jana Ptacinova, Ivo Dlouhy
Summary: This study investigates the fracture micro mechanism of cryogenically treated Cr-V ledeburitic tool steel using scanning electron microscopy and microanalysis. The research finds that small globular carbides produced by cryogenic treatments enhance ductility, while nano-scaled transient carbides within the martensite are more prone to cleavage cracking.
PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON FRACTURE, FATIGUE AND WEAR, FFW 2021
(2022)
Article
Mechanics
Xiaolong Liu, Kelian Luo, Pengcheng Gao, Tao Cong, Xi Wang, Wenjing Wang
Summary: This paper investigates the formation mechanisms of the zig-zag crack region on the shattered rim of railway wheels. The zig-zag crack region, identified as a typical region for crack propagation in rolling contact fatigue behavior, was observed using scanning electron microscopy and transmission electron microscopy. The formation of the zig-zag morphology is attributed to the periodic deflection of the propagation path relative to the initial propagation plane, caused by the limited plastic deformation zone at the crack tip. Grain refinement and secondary cracks in the zig-zag crack region are a result of the large compressive and shear stresses induced by rolling contact loading.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Anastasia Iziumova, Aleksei Vshivkov, Ivan Panteleev, Virginia Mubassarova, Oleg Plekhov, Denis Davydov
Summary: The aim of this study was to investigate the correlation between structural, acoustic emission, and thermal characteristics of fatigue crack growth in titanium alloys. Cluster analysis of the acoustic emission signals revealed two different types of signals observed during the fatigue crack development. It was experimentally demonstrated that the stored energy tends to reach an asymptotic value at the final stage of fatigue crack growth and this is correlated with the twinning process intensification in titanium alloy Ti Grade 2. A correlation was assumed between the stages of change in heat flux, the cumulative energy of the first cluster of acoustic emission signals, and the crack length.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
M. Vieira de Carvalho, I. A. Rodrigues Lopes, F. M. Andrade Pires
Summary: This study investigates the numerical challenges of fracture mechanics models within implicit quasi-static frameworks and proposes an instability criterion. The ratio of cohesive to internal power is identified as a crucial factor. Two strategies for handling fracture problems with instabilities are discussed and a comparative assessment is performed. The study also examines more complex material responses, including transformation-induced plasticity effects.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Thomas Duminy, Aurelien Doitrand, Sylvain Meille
Summary: This study conducted in situ wedge splitting tests on millimeter-size PMMA samples and proposed a method to determine the material tensile strength and critical energy release rate using digital image correlation and a full finite element implementation of the coupled criterion.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Xin Chang, Xingyi Wang, Chunhe Yang, Yintong Guo, Yanghui Wan
Summary: The influence of cyclic thermal shock and high-temperature acid etching on the Mode I fracture of shale was investigated in this study. It was found that cyclic thermal shock severely degrades the strength and fracture toughness of shale, while high-temperature acid etching treatment improves the fracture toughness. These findings are valuable for optimizing process parameters to reduce initiation pressure in deep shale formations.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Liaojun Yao, Mingyue Chuai, Zhangming Lyu, Xiangming Chen, Licheng Guo, R. C. Alderliesten
Summary: Methods based on fracture mechanics have been widely used in fatigue delamination growth (FDG) characterization of composite laminates. This study proposes appropriate similitude parameters to represent FDG behavior with different R-ratios.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Zesheng Zang, Zhonghui Li, Yue Niu, Shan Yin
Summary: This study conducted experiments and recorded signals to investigate the fracture behavior and damage evolution characteristics of coal samples. The results showed that as loading proceeds, the stress, electric potential (EP), and acoustic emission (AE) values increase, and EP and AE signals are excited when stress drops. The fracture behavior of coal samples is altered by flaw inclination, and the destruction mode becomes increasingly complicated. The damage evolution characteristics of coal samples can be evaluated and analyzed by defining the coefficient of variation (CV value) of EP and the b value of AE.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Clotilde Berdin, Nathalie Prud'homme
Summary: In this study, zirconia layers with different fractions of tetragonal phase and thicknesses were tested for multi-cracking behavior. Cracks perpendicular to the tensile direction were observed, showing a blunting effect into the substrate. The ratio of crack spacing at saturation to layer thickness decreased as the layer thickness increased. Unit cell modeling was used to establish a relationship between crack spacing and layer strength, which fell within the bounds of Hu and Evans model and was found to be insensitive to the tetragonal zirconia fraction.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Huadong Zhang, Weichen Kong, Y. H. Liu, Yuh J. Chao
Summary: Williams' series expansion crack tip solution in linear elasticity is modified to include a uniform crack face pressure. Practical methods to calculate T-stress from near crack tip stresses are outlined. The analytical results are consistent with numerical results.
ENGINEERING FRACTURE MECHANICS
(2024)
Article
Mechanics
Jiahao Kong, Haoyue Han, Tao Wang, Guangyan Huang, Zhuo Zhuang
Summary: This paper introduces a phase-field model for polymer foam materials by combining the phase-field method with the crushable foam model. The model is calibrated using experimental data and successfully simulates the fracture processes of polyurethane under different loading conditions. The study is important for the engineering applications of polymer foam materials.
ENGINEERING FRACTURE MECHANICS
(2024)
