Article
Mechanics
Shiv Sahaya Shukla, S. Sajith, K. S. R. K. Murthy
Summary: A simple and efficient specimen geometry for mixed mode (I/II) fracture tests and fatigue crack growth studies has been proposed in this investigation. Through extensive finite element analyses and experimental studies, the proposed specimen geometry shows good agreement with widely used fracture criteria in terms of fracture toughness, indicating its practicality.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2022)
Article
Engineering, Mechanical
Shiv Sahaya Shukla, K. S. R. K. Murthy, S. Sajith
Summary: In this work, mixed mode (I/III) fracture behavior was investigated using a new specimen and an out-of-plane loading fixture compatible with conventional uniaxial universal testing machines. The proposed specimen, a single edge cracked circular (SECC) specimen, can be used for metallic and non-metallic materials under static and fatigue loads. Finite element analyses and experimental fracture studies were conducted, showing good agreement with existing mixed mode (I/III) fracture criteria. The results indicate that the pure mode III fracture toughness is 1.46 times greater than that of mode I, attributed to an increase in the inelastic region around the crack tip. Fractured surface analysis revealed rougher surfaces with increasing mode III component. Preliminary fatigue crack growth studies on Al 7075-T6 using the SECC specimen were also presented, confirming the applicability of the proposed setup for studying mixed mode fracture behavior under static and fatigue loading.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Materials Science, Multidisciplinary
Mohammad Reza Khosravani, Peter Frohn-Soerensen, Bernd Engel, Tamara Reinicke
Summary: This research investigates the fracture behavior and crack propagation of cracked plates in 3D printing. Different fracture modes were obtained by changing the angle between the crack and the applied load. The study uses stereolithography (SLA) technique to fabricate specimens and finite element method and digital image correlation technique to determine stress intensity factors and strain field.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Engineering, Mechanical
Monika Duda, Dariusz Rozumek, Michal Smolnicki, Anna Wybraniec
Summary: The article discusses the results of a study on fatigue fracture in mixed and I + II and I + III modes in heat treated steel 42CrMo4. It presents different mechanical properties resulting from various thermal treatments and demonstrates tests conducted on different sample types and load angles. The research aims to enhance understanding of fatigue crack development under mixed modes and provide valuable insights into the material's behavior under complex loads.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Yifan Li, Martyn J. Pavier, Harry Coules
Summary: The Holed-Cracked Square Plate (HCSP) configuration allows for investigation of I/II mixed-mode fracture in brittle and quasi-brittle materials. Using finite element method, stress intensity factors and T-stress solutions were calculated for various crack lengths and hole diameters. The experimental results on PMMA demonstrated consistent fracture toughness values and agreement with mixed-mode fracture theories.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2021)
Article
Mechanics
Wei Liu, Yulong Li, Zhiqian Zhang, Liyun Yang, Yi Luo, Zhongwen Yue
Summary: This study investigates the mixed-mode I+II fracture characteristics of V-notched rock specimens under impact loads, considering the effects of loading rate, notch angle, and loading angle. Experimental and numerical analysis results show that loading rate has a significant positive effect on the fracture toughness value, but has a negative effect on the crack initiation angle.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Mechanics
Noelig Dagorn, Gerald Portemont, Julien Berthe, Francois Rasselet, Benjamin Bourel, Franck Lauro
Summary: A new specimen called mixed mode double cantilever beam (MMDCB) was developed for characterizing the mixed mode fracture of adhesives under high displacement rates. The results showed that the MMDCB specimen provided consistent evaluations of mixed mode fracture toughness under quasi-static loading and asymmetric high displacement rate. The corrected beam theory with effective crack length was proven to accurately determine the mixed mode fracture toughness up to a displacement rate of 1 m/s.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Mechanics
M. R. M. Aliha, S. S. Samareh-Mousavi, M. M. Mirsayar
Summary: This paper investigates the effect of loading rate on the mixed-mode I/II fracture behavior of PolymethylMethacrylate (PMMA) using a novel fracture test specimen, the short bend beam (SBB). Two fracture criteria, MTS and GMTS, are employed to predict the onset of fracture and the fracture initiation angle in different loading rates. The study reveals that the critical distance (rc) and the T-stress term play important roles in the fracture behavior under different loading rates.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Engineering, Mechanical
Reza Jalayer, Behnam Saboori, Majid Reza Ayatollahi
Summary: A new test specimen is proposed for investigating mixed mode I/II/III fracture of materials. This test specimen creates mixed mode I/III loading conditions by displacing the position of an inclined crack from the middle of the rectangular specimen, in addition to mode II loading under anti-symmetric four-point bending. The experimental fracture loads of PMMA specimens are compared with theoretical predictions, showing satisfactory consistency.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Mechanical
Arsalan Ajdani, Majid R. Ayatollahi, Lucas F. M. da Silva
Summary: An improved SCB specimen is introduced for obtaining the mixed mode fracture envelope of a ductile adhesive with a significant fracture process zone ahead of the crack tip. The proposed test procedure is simple and does not require special loading fixtures, covering the whole range of mixed-mode ratios. Experimental results show that crack growth does not affect the mixed-mode ratio of the adhesive joint.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Energy & Fuels
Peiwang Cao, Tao Zhou, Yang Ju, Jianbo Zhu
Summary: It is still unclear how different loading angles (beta) affect the mixed mode I/II fracture behavior of rock. To investigate this, cracked straight through Brazilian disc tests were performed on sandstone under various beta. The results show that the effect of beta on peak load and crack propagation velocity is slight, but there is a linear increase in mixed mode I/II fracture toughness with increasing beta.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Article
Mechanics
Qikun Xie, Hongyu Qi, Shaolin Li, Xiaoguang Yang, Duoqi Shi
Summary: One of the most common damage modes of aero-engine hot-end components is crack, which is typically in a mixed-mode and under elastoplastic conditions due to the complicated geometry and harsh working environment. The phase-field fracture method has recently attracted extensive attention as a numerical simulation method. However, attention toward material damage and crack initiation before the crack emerges is lacking in solving the problem of elasto-plastic mixed-mode fatigue crack propagation. In this study, an enhanced phase-field fracture method is used to address this issue and predict the propagation behavior of the elastoplastic mixed-mode fatigue crack. The effect of some parameters of this model is analyzed. This achievement is a significant contribution to the safety of aircraft engines and a novel method that can be further improved to solve problems in the future.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Rafael L. Moresco, Eduardo Bittencourt
Summary: The study found that crack propagation in elastic specimens is controlled by a resultant stress intensity factor, while in elastic-plastic specimens, it also depends on the energy dissipated in the volume. The rotation of the plastic zone around the crack tip is related to the phase angle between fracture modes.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Quanqi Zhu, Diyuan Li, Xibing Li, Zhenyu Han, Jinyin Ma
Summary: The cracked straight through Brazilian disc (CSTBD) specimen was used to investigate the I/II mixed mode static fracture of diorite in this study. The results showed that the fracture mechanical behavior and trajectories were influenced by the crack angle. Fracture energy and crack mouth opening displacement (CMOD) were characterized, and a fracture energy calculation method considering primary crack growth was proposed. The proposed EEMTSN criterion had the best prediction effect on the mixed mode fracture toughness of diorite.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Gyoko Oh
Summary: Through fatigue tests and data evaluation, fatigue strengths, limits, lives, and failure probabilities under different loading conditions can be predicted. The notch factors, fatigue strengths, and scatters of welded components mainly depend on the weld flank angle and material factors.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
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)