Article
Energy & Fuels
Jianhua Wen, Zhan Tang, Ashley P. Dyson, Ali Tolooiyan
Summary: The research investigates the fracture characteristics of Victorian Brown Coal and its relationship with joint compressive strength, finding that pre-fractured VBC shows reduced uniaxial compressive strength under various crack angles, with significantly different fracture propagation characteristics. Experimental results suggest that pre-existing crack angles alter the shape of the stress-strain curve, presenting a range of unconfined compressive strengths and crack initiation strengths.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Metallurgy & Metallurgical Engineering
Qing-qing Shen, Qiu-hua Rao, Zhuo Li, Wei Yi, Dong-liang Sun
Summary: The maximum Mode I and Mode II stress intensity factors of inclined parallel multi-crack were calculated using complex function and integration method to analyze their interacting mechanism and determine the strengthening and weakening zone of SIFs. A multi-crack initiation criterion was established based on the ratio of maximum tension-shear SIF to predict crack initiation angle, load, and mechanism.
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
(2021)
Article
Engineering, Multidisciplinary
Zeyuan Zhou, Ming Yu, Xinfeng Wang, Zaixing Huang
Summary: This paper presents a new nonlocal continuum formulation called Peridynamics, which can predict crack nucleation, branch, and propagation in materials and structures using a meshfree discrete technique. The motion equation of Peridynamics with boundary traction is improved by simplifying the boundary transfer functions. The critical cracking load and fracture angles of a plate with multiple cracks under uniaxial tension are calculated, and the results are consistent with classical fracture mechanics. The fracture mode and crack propagation path are also determined. The calculation demonstrates that the peridynamic motion equation with boundary conditions can conveniently and accurately simulate the brittle fracture process in a plate with multiple cracks.
CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES
(2023)
Article
Engineering, Geological
Somaie Jolfaei, Ali Lakirouhani
Summary: This paper establishes a simple analytical model by combining stress distribution around elliptical wellbores and material tensile strength criterion to predict the fracture initiation location and initiation pressure in elliptical wellbores. The results show that the fracture initiation location is in the direction of the longest diameter of the wellbore if the in situ stresses are isotropic, and the initiation pressure decreases with the increase of the shape parameter. If the in situ stresses are non-isotropic, a critical shape parameter is defined. If the shape parameter is less than the critical value, the fracture initiation occurs along the maximum in situ stress and the initiation pressure increases with the increase of the shape parameter, while if the shape parameter is greater than the critical value, the fracture initiation occurs in the direction of the minimum in situ stress and the initiation pressure decreases with the increase of the shape parameter. This model can be applied to estimate the fracture initiation pressure and position in elliptical cavities in both field and laboratory settings.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2023)
Article
Chemistry, Multidisciplinary
Lizhou Wu, Jianting Zhou, Jun Yang, Jingzhou Xin, Hong Zhang, Bu Li
Summary: This study investigates the fracture propagation of single-crack concrete specimens under compressional loading and proposes a radial shear stress criterion to examine the stress intensity factor of the pre-crack specimens. Experimental and numerical results show that the existence of cracks considerably weakens the strength of the specimens, and the distribution and width of the cracks have a significant effect on the specimen strength.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Mechanical
Hanlin Wang, Satoyuki Tanaka, Selda Oterkus, Erkan Oterkus
Summary: This study investigates mixed-mode fatigue crack propagation analysis using ordinary state-based peridynamics. By introducing the concept of remaining life, the fatigue crack nucleation and propagation are simulated in the PD framework. The PD fatigue modelling and crack path prediction are carefully studied, and the maximum circumferential stress criterion is introduced for comparison. The interaction integral and peridynamic differential operator are used to evaluate fracture mechanics parameters. Two pre-cracked structures under mixed-mode loading conditions are provided with validations from reference solutions.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Xin Lv
Summary: In classical fracture mechanics theory, it is believed that crack surface is open under tension and closed under compression. However, under small angle uniaxial tension, the stress field at crack tip is small because the crack surface may also be closed. This paper considers both the far-field stress and the possible stress acting on the crack surface, and derives the stress field at crack tip. The crack initiation angles of open or closed cracks under uniaxial tension or compression are studied based on the generalized maximum tangential stress criterion.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Metallurgy & Metallurgical Engineering
Lin Lang, Zhe-ming Zhu, Chang-lin Zhou, Lei Zhou, Meng Wang, Lu Wang
Summary: The study proposes a large-size double-cracked concave-convex plate (DCCP) specimen configuration for simultaneously measuring the initiation toughness of pure mode I and mode II cracks. Through experiments and numerical research, it is found that the dynamic initiation toughness increases with the increase of loading rate, while the crack initiation time decreases with increasing loading rate. Additionally, the initiation toughness of mode II crack is 0.5 times that of mode I crack when subjected to the same loading rate. For the pre-crack in the vicinity of the bottom, an increase in its length leads to a gradual decrease in the dynamic initiation toughness of pure mode I crack, while the dynamic initiation toughness of pure mode II crack remains relatively constant.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2022)
Article
Engineering, Mechanical
Lei Zhou, Leijun Ma, Zheming Zhu, Yuqing Dong, Jianwei Huang, Shenghua Cui
Summary: This study explored the coupling effect of elliptical cavities and cracks on the dynamic stability and failure modes of tunnels. Through numerical simulations and model tests, the crack coalescence behavior, crack initiation time, and stress field around the elliptical cavity were determined. The results showed that the long and short axes of the elliptical cavity have a significant influence on crack behavior and stress distribution, with the long axis having a greater effect. The inclination angle of the elliptical cavity also plays a crucial role in the stability and initiation behavior of the crack, with the lowest stability observed at an inclination angle of 90 degrees.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Computer Science, Artificial Intelligence
Deepak Gupta, N. Natarajan
Summary: The study introduces a novel density weighted approach for PLSTSVR to handle input samples in the presence of outliers, boosting the performance of PDWLSTSVR in terms of efficiency. The weights are determined with the help of k-Nearest Neighbour (k-NN) distance. Further, the proposed PDWLSTSVR outperforms the RF, ELM, LSSVR and PLSTSVR in terms of all evaluation measures when applied to the real-world application of predicting the UCS of rock samples.
NEURAL COMPUTING & APPLICATIONS
(2021)
Article
Engineering, Mechanical
Elzbieta Bura, Andrzej Seweryn
Summary: This paper presents the results of FEM numerical calculations on the plastic strain and stress fields under critical loading conditions. The study verified the effectiveness of using an elastic-plastic material model to describe PMMA and proposed a stress-strain fracture criterion based on the measured stress and plastic strain values at critical points.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Mining & Mineral Processing
Zhongwei Wang, Quansheng Liu
Summary: The study proposed a strength criterion for soft rocks, which includes two independent parameters: uniaxial compressive strength and f(joint) for characterizing rock mass quality. Comparisons showed that the new criterion generally produced a better fit for estimating triaxial and true-triaxial strengths, even without triaxial data.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Mechanical
Fengjin Zhu, Hongyan Liu, Leihua Yao, Gang Mei
Summary: The study presents a new Maximum Tangential Strain criterion to predict crack initiation under compression, analyzes the factors affecting K-II and the effects of T-stress on tangential strain at the crack tip. Consistent results are observed between experimental measurements and proposed models.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Engineering, Mechanical
Li-Zhu Jin, Chang-Yu Zhou, Chen-Yang Yu, Qi Pei, Le Chang, Xiao-Hua He
Summary: Through theoretical analysis and experimental study, crack initiation characteristics of HT200 and PMMA under compression were investigated, demonstrating that considering T-stress components in the modified fracture criterion is more consistent with experiments and crack initiation angle is related to material properties.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Engineering, Geological
Xuhai Tang, Siji Tao, Ping Li, Jonny Rutqvist, Mengsu Hu, Lei Sun
Summary: In this study, the mechanisms of frost cracking as a result of freeze-thaw cycling, confining stress, and the interaction of multiple cracks were investigated using experimental, theoretical, and numerical approaches. The experimental and numerical results showed that frost cracks tend to propagate in the direction of maximum principal stress, and the position and orientation of initial cracks significantly influence the interaction effect between two frost cracks.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Mechanical
Zhuang Sun, Yixin Zhao, Yirui Gao, Sen Gao, Davide Elmo, Xindong Wei
Summary: In this study, the modified semi-circular bending test was used to investigate the fracture toughness of coal samples with different sizes and bedding angles. The results showed that the fracture toughness of coal exhibits size effect and anisotropy. The crack initiation and propagation in hydraulic fracturing of coal seam can be influenced by bedding angles.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Ruiming Zhang, Kai Ma, Wenzhu Peng, Jinyang Zheng
Summary: The fatigue crack growth rates of 4130X steel in different hydrogen concentrations were measured, and the influence of hydrogen on crack behavior was analyzed. Results show that the crack growth rate increases with increasing hydrogen pressure, reaching a threshold at 87.5 MPa.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Hien Do, Phuc L. H. Ho, Canh V. Le, H. Nguyen-Xuan
Summary: In this study, a new method for determining the limit loads of fracture structures using the pseudo-lower bound method with adaptive quadtree meshes is proposed. The method overcomes the volumetric locking problem and handles the challenge of hanging nodes during refinement procedure by using quadtree meshes. The effectiveness of the approach is demonstrated through numerical validation.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Weimin Song, Yuxin Fan, Hao Wu, Liang Zhou
Summary: This study proposed a novel test method to characterize the I-II mixed fracture toughness of asphalt pavement and investigated the effects of reclaimed asphalt pavement (RAP) and loading rate. The results showed that loading rate and inclusion of RAP had positive effects on fracture toughness.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Zida Liu, Diyuan Li, Jianqiang Xia, Quanqi Zhu
Summary: In this study, the influence of flaw inclinations on the failure mechanism of fissured granite specimens was analyzed through a series of experiments. A quantitative method combining deep learning and scanning electron microscope was employed to identify the mesoscopic fracture mechanism of macroscopic cracks. The results indicated that the failure of fissured specimens was mainly caused by tensile stress and shear stress.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Jiabing Zhang, Yiling Chen, Ronghuan Du, Xianglian Zhao, Jun Wu
Summary: This study investigated the mechanical characteristics and crack propagation behavior of sandstone-like samples with single cracks under freeze-thaw cycles. The results demonstrated the significant effects of crack angle and freeze-thaw cycles on the compressive strength and stability of the samples. Confining pressure inhibited the freeze-thaw deterioration, and the acoustic emission signals exhibited good consistency with the stress-strain curves. The simulation results matched well with the experimental results, and five crack propagation modes were proposed.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Felix Boedeker, Pauline Herr, Anders Biel, Ramin Moshfegh, Stephan Marzi
Summary: Cohesive Zone Models with finite thickness are widely used for fracture mechanical modeling. Computational homogenization techniques are crucial for the development of advanced engineering materials. FFT-based homogenization scheme shows potential in reducing computational effort and has practical applications.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Sobhan Pattajoshi, Sonalisa Ray, Yugal Kishor Joshi
Summary: In this work, a novel multi-layer composite structure is proposed for protective shelter design. The dynamic behavior and mechanical performance of the multi-layer composite under projectile impact loading are investigated. The proposed composite target demonstrates enhanced penetration resistance and lesser damage compared to its reinforced concrete monolayer counterpart. An analytical model is also developed to predict the forces transmitted to the lowest layer for design purposes.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
H. M. Shodja, M. T. Kamali, B. Shokrolahi-Zadeh
Summary: This study proposes a semi-analytical method for calculating the stress intensity factor of an internally pressurized eccentric annular crack. By using hypersingular integral equations and conformal mapping, accurate values of SIFs along the crack edges can be obtained. The material properties of the elastic matrix do not affect the SIF values, as demonstrated through the investigation of geometric parameters.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Wen Hua, Zhanyuan Zhu, Wenyu Zhang, Jianxiong Li, Jiuzhou Huang, Shiming Dong
Summary: Accurate assessment and prediction of fracture behavior in cracked materials using mixed mode fracture criteria are crucial in fracture mechanics. This study comprehensively reviewed modified fracture criteria that incorporate T-stress for mixed mode I-II cracks. A comparative analysis was conducted between experimental results and theoretical predictions for five different cracked configurations. The study also discussed the effect of T-stress on crack initiation angle and fracture toughness, providing suggestions. The results showed variations in predictive accuracy across different cracked configurations due to disparities in T-stress. However, similar predictions were observed for semi-circular bend and edge-crack triangular specimens due to their similar biaxial stress ratio B. Different fracture criteria were suitable for different cracked configurations with positive or negative T-stresses.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Qing-qing Shen, Qiu-hua Rao, Wei Yi, Dian-yi Huang
Summary: This study proposes a theoretical approach to forecast multi-crack propagation trajectories in a finite plate. By calculating the stress intensity factor (SIF) and analyzing the influence of crack size, the criteria for crack initiation and propagation in a finite plate are established. Experimental results demonstrate that the SIF of multiple cracks in a finite plate is consistently larger than that of an infinite plate.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Songbai Li, Qiyun Zhu, Zhizhong Lu, Hongzhi Yan, Chu Zhu, Peize Li
Summary: This study investigates the effects of laser heating and laser shot peening on fatigue life of AA2524, and predicts the fatigue life using artificial neural networks and support vector regression models. The results show that laser heating and laser shot peening can significantly improve the fatigue life, and the neural networks have better prediction ability.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
V. Shlyannikov, A. Sulamanidze, D. Kosov
Summary: This paper presents experimental crack-growth data for thermomechanical fatigue conditions in nickel-based alloy components. The crack-growth experimental results are interpreted using finite element analyses and multi-physics numerical calculations. The results show that crack growth rate is slower under isothermal pure fatigue conditions, while it is faster under thermomechanical cyclic deformation conditions.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Tairui Zhang, Xin Ma, Bin Yang, Wenchun Jiang, Zhiqiang Ge, Xiaochao Liu
Summary: This study experimentally investigated the fracture toughness distributions in dissimilar metal welds. The predictions of fracture toughness were made using three criteria and an energy release rate model. The results showed that using the critical strain criterion and ERR model resulted in higher consistency compared to mini-CTs, while the predictions using the critical stress criterion had high dispersion. The study also investigated the source of errors through damage developments and SEM observations.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)
Article
Engineering, Mechanical
Yike Dang, Zheng Yang, Xiaoyu Liu, Jianghao Guo
Summary: This study uses discrete element modeling to examine bedded rock failure with parallel defects. It is found that bedding influences crack propagation direction but has limited impact on final failure. Shear failure accumulates at the bridge area and defect tip, while tensile failure occurs during nucleation region development.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2024)