Article
Mechanics
Mahsa Sakha, Morteza Nejati, Ali Aminzadeh, Saeid Ghouli, Martin O. Saar, Thomas Driesner
Summary: This study evaluates the accuracy of three fracture growth theories in predicting crack trajectories in anisotropic rocks through comparison with new experimental data. The results show that anisotropy can offset or reinforce the loading influence in determining the direction of crack growth, depending on the loading configurations. It is demonstrated that the modified forms of the maximum tangential stress (MTS) and maximum energy release rate (MERR) criteria give better predictions of fracture growth paths compared to the modified maximum strain energy density (MSED) criterion.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Engineering, Mechanical
Adel Esmaeili, Bijan Mohammadi, Alireza Yousefi
Summary: The present study aims to extract fracture parameters and analyze crack behavior through a novel mixed-mode fracture criterion and the digital image correlation method. Key findings include the variation of mode I and mode II stress intensity factors with crack inclination angle, as well as the accuracy of predicting crack initiation angles. Experimental outcomes are consistent with finite element modeling results and comparisons with the MERR and MTS criteria. Simpson's rule is applied to calculate the J-integral, contributing to a comprehensive understanding of crack behavior.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Manufacturing
Nawres J. Al-Ramahi, Roberts Joffe, Janis Varna
Summary: An alternative method based on maximum hoop stress analysis is demonstrated for predicting crack propagation direction in the adhesive layer of bonded stiff materials, avoiding the need for extensive computational resources. Validation is done using fracture mechanics approach, followed by a parametric study on factors influencing crack propagation.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2021)
Article
Chemistry, Multidisciplinary
Xin Pan, Jiuzhou Huang, Zhiqiang Gan, Shiming Dong, Wen Hua
Summary: This study investigated the coupling effect of multiple variables on fracture parameters and proposed a three-point bending specimen with an inclined crack for mixed-mode fracture research. The fracture parameters were obtained through experiments and finite element analysis, showing that the generalized maximum tangential strain energy density factor criterion considering T-stress can better predict the mixed-mode fracture toughness.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Mechanical
Dongdong Chang, Ran Liu, Xiaofa Yang, Zekai Huang, Rong Wang, Hong Zuo
Summary: This study proposes a new criterion based on the ratio of two strain energy densities for predicting the direction and fracture resistance of crack initiation. Experimental and theoretical analysis show that this criterion has higher accuracy in predicting crack initiation in ductile materials.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Chemical
Mohammed El Yaagoubi, Jens Meier
Summary: This article investigates the prediction of crack growth angles of internal cracks in EPDM rubber under mixed mode loading. The determination of the strain energy density factor successfully predicted the crack growth angles, which showed very good accordance with the experimental measurements.
POLYMER ENGINEERING AND SCIENCE
(2021)
Article
Mechanics
Yao-Min Li, Bin Zhang
Summary: Crack branching in graphene under complex stresses is investigated using molecular dynamics simulations and boundary-layer models. By considering the anisotropic fracture toughness of hexagonal graphene, a Wulff-like curve is plotted based on the maximum energy release rate (MERR) criterion, showing the direction of crack kinking is consistent with that of the weak fracture toughness along the zigzag edge. The angle of crack kinking prefers 0 degrees /30 degrees /60 degrees, contrary to the angle predicted by the maximum circumferential stress criterion. The T-stress along the crack front, obtained through the over-deterministic method, can indicate the possibility of kink formation, especially for zigzag cracks. This study incorporates the Wulff-like curve and MERR criterion to accurately predict nanocrack paths in graphene.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Can Wang, Kyvia Pereira, Dagang Wang, Aleksandr Zinovev, Dmitry Terentyev, Magd Abdel Wahab
Summary: In this paper, a numerical crack growth analysis is conducted using the MTS criterion and its extension, taking into account the contact stress between the crack surfaces. The focus is mainly on the influence of loading phase difference (f) on crack propagation behavior in fretting fatigue. The effect of initiation characteristics, including crack initiation position and direction, is studied using LEFM theory, and it is found that the predicted crack path and lifetime match well with experimental results.
TRIBOLOGY INTERNATIONAL
(2023)
Article
Engineering, Mechanical
Zahra Khaji, Mahdi Fakoor
Summary: This article proposes a Semi-theoretical criterion for assessing the fracture of composite materials. The criterion utilizes experimental data under mixed-mode I/II loading to accurately predict the fracture behavior of orthotropic materials. Fitting experimental data into the criterion improves the accuracy of fracture estimation.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Chemistry, Multidisciplinary
Sergio M. O. Tavares, Paulo M. S. T. de Castro
Summary: The concept of equivalent stress intensity factor K-eq is used to study fatigue crack growth in mixed-mode situations. This study highlights the problem of having multiple alternative definitions of mixed mode K-eq, which can lead to different results. Several previously unanalyzed K-eq definitions were compared, and their values calculated according to various criteria. Differences were found in the fatigue crack growth laws based on different K-eq definitions, and the requirements for candidate K-eq definitions were discussed. A data-driven modeling methodology, supported by material characterization and structure monitoring, may help overcome these shortcomings.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Mechanical
Nandu V. Namboothiri, P. Marimuthu, S. Suresh Kumar
Summary: Gears are crucial components in various mechanical machines, cars, and wind mills. This study investigates the effect of backup ratio on the fatigue crack behavior of symmetric and asymmetric spur gears under mixed-mode fracture. The findings show that the fracture resistance of gears increases with an increase in rim thickness and backup ratio, leading to improved crack stability.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Multidisciplinary
Yang Jiang, Cunyi Li, Chi Wu, Timon Rabczuk, Jianguang Fang
Summary: Crack-direction-based decomposition is used to control the propagation of cracks in a phase field modelling context. The proposed double-phase field model extends this strategy to complex crack modelling in a 3D setting with plastic deformation. The model accurately captures different crack modes and has been proven effective in solving complex 3D problems.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Mechanics
Cungen Wang, Shuhong Wang
Summary: This study modified the generalized maximum tangential stress criterion by considering parallel and perpendicular nonsingular stresses, successfully simulating open and closed crack propagation and modeling. The simulation results were in good agreement with experimental data.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Mechanical
Ritika Singh, Subir Das
Summary: This article investigates the behavior of an arbitrary oriented crack that crosses the interface under thermo-mechanical loading. Mathematical methods are used to derive the expressions of stress intensity factors (SIFs) and strain energy release rates (SERRs) of the crack, and the results are validated. Graphical presentations are provided to better understand the behavior of the crack under different parameters.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Polymer Science
Tao Yang, Ling Liu, Xiaolin Li, Liqun Zhang
Summary: In this study, binary and ternary silicate/silicone elastomer dielectric composites were prepared by incorporating talc (Tl), wollastonite (Wl) and halloysite nanotube (HNT) into methyl vinyl silicone rubber (MVSR). Tl and Wl acted as physical barriers to prevent HNT aggregation, simplifying the preparation process. Tl and Wl effectively improved the breakdown strength of MVSR, while HNT significantly increased the dielectric constant of MVSR. The addition of Tl or Wl resulted in higher actuated strain compared to pure MVSR, and the ternary composites Tl-HNT/MVSR and Wl-HNT/MVSR exhibited improved electromechanical properties due to the combined increase in dielectric constant and breakdown strength.
