Article
Construction & Building Technology
Md Jihad Miah, Francesco Lo Monte, Roberto Felicetti, Pierre Pimienta, Helene Carre, Christian La Borderie
Summary: Explosive spalling of concrete exposed to fire is the phenomenon of shards being expelled from the heated face during rapid heating. This can seriously compromise the integrity of reinforced concrete structures and expose reinforcing bars to flames. Factors such as heating rate, specimen geometry, concrete grade, and external loads influence the occurrence of fire spalling. This study focuses on the role of external loading combined with pore pressure and thermo-mechanical stresses in triggering spalling in normal-strength concrete.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Minghao Huang, Lingyu Wang, Chenchong Wang, Anna Mogucheva, Wei Xu
Summary: Deformation-induced martensitic transformation (DIMT) is considered as a key strengthening mechanism in advanced high-strength steels (AHSS). However, systematic investigations on the transformation at high strain-rates are limited due to experimental difficulties. In this study, interrupted Charpy tests were conducted to study the transformation sequence of DIMT under high strain-rates. The results revealed that the nucleation sites and morphology of transformed alpha'-martensite changed with the increasing austenite grain sizes (AGSs), and the transformation sequence can be explained by considering the stacking fault energy and twinning nucleation stress of austenite.
MATERIALS CHARACTERIZATION
(2022)
Article
Nanoscience & Nanotechnology
Mengkai Lu, Zheng Zhang, Jianke Du, Tao Shen, Xuze Lu
Summary: This study investigates the propagations of surface acoustic waves in two-dimensional solid/fluid phononic crystal structures. The distribution of bandgaps varies with fluid height, with mercury showing higher sensitivity to bandgap changes compared to water. Furthermore, transmission properties of surface acoustic waves are analyzed for phononic crystals filled with different mercury heights, showing effective inhibition of wave propagation corresponding to the bandgap frequency. The results provide valuable insights for the practical design of tunable surface acoustic wave phononic crystals.
Article
Engineering, Geological
Babak Khadivi, Amin Heidarpour, Qianbing Zhang, Hossein Masoumi
Summary: Tensile strength is an important mechanical property of rock and rock-like materials for the design of structures on or within rock masses. Brazilian testing has been widely used to estimate this property, but the fracturing process at micro and macro scales has not been well characterized. In this study, Acoustic Emission and high-speed imaging techniques were used to investigate the fracturing process of different rock types under Brazilian loading. The results showed that tensile microcracks initiate before shear microcracks, and the microcracking mechanism transitions from tension to shear in brittle samples. The size of the samples also affects the tensile microcracks, and different cracking mechanisms were observed at the macro scale.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Green & Sustainable Science & Technology
Xinyu Wang, Guoqing Zhu, Deqiang Cheng, Bin Miao, Fanbao Chen, He Tian
Summary: This study investigates the early warning signs of damage during the coal mass deformation process by combining the apparent resistivity (AR) and acoustic emission (AE) monitoring. The results show a good correlation between the AR and AE signals and the applied load, providing new ideas for monitoring and early warning systems for coal and rock dynamic disasters.
Article
Chemistry, Multidisciplinary
Andronikos Loukidis, Dimitrios Tzagkarakis, Antonios Kyriazopoulos, Ilias Stavrakas, Dimos Triantis
Summary: Acoustic emissions (AEs) and pressure stimulated currents (PSCs) were recorded simultaneously to investigate their behavior and detect precursory indicators of cement mortar specimens under mechanical compressive loading, focusing on the AEs and PSC signal near fracture. The results showed strong similarities between the variations of the PSC signal, AE hits occurrence rate (F-function), and AE hits energy release rate (P-function). Combining the PSC signal and AE data can provide clear pre-failure indicators.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Mechanical
Fei Xue, Zhongqin Lin, Tianzuo Wang
Summary: In order to study the mode-I fracture process of hard brittle rocks, semi-circular bending (SCB) experiments were conducted with concurrent monitoring of acoustic emission (AE) and digital image correlation (DIC). The results showed that all specimens exhibited ductile fracture behavior and the fracture planes deviated from the ligament plane due to interference from mineral crystals or pre-existing weak surfaces within the intergranular boundaries. The cracking process was divided into four stages: microcrack initiation preparation, microcrack initiation and stable propagation, macrocrack formation and unstable propagation, and macrocrack coalescence. The length of the fracture process zone (FPZ) remained constant as the crack propagated, while the length of the traction-free zone (TFZ) increased. The crack lengths determined based on AE locations and energy statistical analysis matched well with the crack lengths obtained from DIC.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Chemistry, Analytical
Alexander Machikhin, Anton Poroykov, Vladimir Bardakov, Artem Marchenkov, Daria Zhgut, Milana Sharikova, Vera Barat, Natalia Meleshko, Alexander Kren
Summary: Fatigue cracks in rails and train parts can cause multiple railroad accidents. This study proposes a combination of acoustic emission testing and digital image correlation for early detection and accurate measurement of fatigue crack growth.
Article
Engineering, Mechanical
Xudong Chen, Jianhui Tang, Nan Zhang, Feng Dai, Mingdong Wei
Summary: This study comprehensively presents the fracture behavior of cracked rocks subjected to prepeak and postpeak cyclic loads. The experiments revealed that in prepeak loading-unloading cycles, deformation of the specimen gradually developed from elastic to elastic-plastic, with tension-dominated microcracking. In postpeak cycles, parameters such as horizontal strain and crack length generally increased cumulatively with the cycle number but locally decreased with unloading, while microcracks were still produced during unloading and shear-type AE signals increased.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Engineering, Mechanical
Xudong Chen, Dandan Shi, Jinhua Zhang, Xiyuan Cheng
Summary: Self-compacting concrete has excellent workability under its own dead weight, making it suitable for construction projects where vibrations are difficult. This study conducted three-point bending tests on notched self-compacting concrete beams with varying loading rates and notch-to-depth ratios. Acoustic emission analysis and digital image correlation techniques were used to study crack propagation behavior and fracture performance.
JOURNAL OF STRAIN ANALYSIS FOR ENGINEERING DESIGN
(2021)
Proceedings Paper
Engineering, Aerospace
Eleni Korda, Eleni Tsangouria, Didier Snoeck, Geert De Schutter, Dimitrios G. Aggelis
Summary: This study aims to obtain real-time information on the ongoing physical processes in fresh concrete using Acoustic Emission (AE) and Digital Image Correlation (DIC), especially when admixtures such as SuperAbsorbent Polymers (SAPs) are added. The results show that SAPs mitigate settlement and shrinkage in early-age concrete, but their activation is delayed under windy conditions.
NONDESTRUCTIVE CHARACTERIZATION AND MONITORING OF ADVANCED MATERIALS, AEROSPACE, CIVIL INFRASTRUCTURE, AND TRANSPORTATION XVII
(2023)
Article
Public, Environmental & Occupational Health
Marziye Pirani, Mohammad Raza Monazzam, Seyed Qasem Pourjandaghi
Summary: This study aimed to improve the acoustic properties by synthesizing polyurethane nanocomposite foams, and found that the addition of silica nanoparticles enhanced the sound absorption of foams.
JOURNAL OF HEALTH AND SAFETY AT WORK
(2021)
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)