Article
Construction & Building Technology
Xiaofei Hu, Huiqian Xu, Xun Xi, Peng Zhang, Shangtong Yang
Summary: This paper develops a meso-scale phase field model for concrete cover cracking induced by corrosion of multiple reinforcements. The model is verified against experimental results, and the effects of reinforcement spacing, cover thickness, and ITZ fracture properties on concrete cover cracking are investigated. The model captures various toughening mechanisms and enables high fidelity numerical predictions.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yangyang Sun, I. V. Alexandrov, Yuecheng Dong, R. Z. Valiev, Hui Chang, Lian Zhou
Summary: This study systematically investigates the low cycle fatigue behavior and fracture characteristics of Ti-6Al-4V-0.55Fe alloy with bimodal microstructure. The alloy exhibits continuous softening behavior at both high and low strain amplitudes, with different crack initiation sites and fatigue striation characteristics observed at different strain amplitudes. The LCF life of Ti-6Al-4V-0.55Fe is similar to that of Ti-6Al-4V at high strain amplitudes and much higher at low strain amplitudes due to the extra resistance provided by Fe microalloying.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Nanoscience & Nanotechnology
Motoki Sakaguchi, Yoshinori Niwa, Wenxiang Gong, Keisuke Suzuki, Hirotsugu Inoue
Summary: The study found that at high temperatures, the fatigue crack growth resistance of the triplex microstructure is significantly increased, mainly due to the higher volume fraction of ductile p phase. Meanwhile, the fatigue crack growth threshold in different microstructures and temperatures is almost comparable and shows the same temperature dependency.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Engineering, Mechanical
Gaoge Xue, Takashi Nakamura, Nao Fujimura, Kosuke Takahashi, Hiroyuki Oguma, Akihisa Takeuchi, Masayuki Uesugi, Kentaro Uesugi
Summary: The full-life growth behaviors of an internal fatigue crack in a beta titanium alloy were non-destructively monitored using in situ synchrotron radiation multiscale computed tomography. The crack fronts at various cycles were superimposed on the fracture surface from the perspective of crack growth stages. The crack propagation process consisted of multiple facets formation and subsequent growth into the matrix and was dominated by the former process. The crack opening and blunting behaviors triggered crack growth from the facets to the surrounding matrix. The overall crack propagation rate of the internal crack was revealed to be slower than the surface crack.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
Katelyn Jones, William D. Musinski, Adam L. Pilchak, Reji John, Paul A. Shade, Anthony D. Rollett, Elizabeth A. Holm
Summary: This study utilized computer vision and machine learning techniques to predict qualitative characteristics and quantitative values of Ti-6Al-4V fracture surfaces from fatigue crack growth tests. The study found that Convolutional Neural Networks (CNNs) focused on different features based on the length scale of the image, and also determined a lower limit field of view and confirmed the effectiveness of transfer learning.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Engineering, Mechanical
Fumiyoshi Yoshinaka, Gaoge Xue, Nao Fujimura, Takashi Nakamura
Summary: The study on small crack propagation tests conducted on Ti-6Al-4V specimens under varying vacuum pressures showed that crack initiation life increased and crack propagation rate decreased with decreasing vacuum pressure. Fractographic features varied, with angular surfaces in air and under 10(0) Pa, and granular features below 10(-2) Pa. The window periods formed an oxidized surface coverage which influenced the crack propagation rate and fracture surface features. Surface cracks under 10(-4)-10(-6) Pa exhibited characteristics similar to internal cracks, suggesting a high vacuum environment around the internal cracks.
INTERNATIONAL JOURNAL OF FATIGUE
(2021)
Article
Engineering, Mechanical
Yang Liu, Xiang Zhang, Caglar Oskay
Summary: This manuscript conducts a comparative study on different fatigue indicator parameters to evaluate their ability to predict the location of fatigue crack nucleation in near-alpha titanium alloy microstructures. The results show that some of the selected parameters can accurately predict the critical initiation locations, which are consistent with the fractography measurements.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Mechanical
Vinh T. Le, Ha H. Bui, Giang D. Nguyen, Jayantha Kodikara, Didier Bodin, James Grenfell
Summary: This paper presents a constitutive model that considers the strain discontinuity across fracture planes and describes the fatigue behavior in cemented materials. The model effectively captures the significant influence of stress amplitudes on the fatigue lives of materials, making it an essential tool for predicting and mitigating fatigue-induced damage.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Dentistry, Oral Surgery & Medicine
Chao Liu, Atilim Eser, Thomas Albrecht, Vasiliki Stournari, Monilza Felder, Siegward Heintze, Christoph Broeckmann
Summary: The Weibull modulus and characteristic strength of three dental ceramic materials in water were determined. The results showed that the polycrystalline yttria-stabilized zirconia had the highest Weibull modulus and strength, while glass ceramic materials had lower values. The subcritical crack growth parameters for the materials in water were also different, with a significant decrease in strength observed over time.
Article
Nanoscience & Nanotechnology
Zhihong Wu, Hongchao Kou, Jinshan Li, Nana Chen, Zhicheng Xi, Fan Sun, Frederic Prima
Summary: In this study, low-cycle fatigue tests were conducted on the dual phase titanium alloy Ti-5Al-7.5V at room temperature to investigate the deformation mechanisms and crack initiation. It was found that planar dislocation slip, localized at the basal and prismatic planes of the alpha phase, was the primary deformation mode. Multiple slips occurred simultaneously within a single grain. Microcracks were observed along the basal slip bands, but were confined within the primary alpha grains without propagating to the surrounding transformed beta matrix. The presence of silicides in contact with the microcracks and slip bands did not lead to crack initiation. It remains unclear whether the silicides can act as dislocation sources for planar slips and facilitate crack nucleation.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Energy & Fuels
Yu Wang, Chun Zhu, Manchao He, Xiao Wang, Huilin Le
Summary: This study investigates the effects of freeze-thaw weathering and impact disturbances on the dynamic fracture and instability characteristics of marble. Experimental and CT scanning results reveal that freeze-thaw treatment leads to degradation of marble structure and a decrease in the cumulative impact number. The strain rate is quadratically correlated with the freeze-thaw cycles and impact number, while the dynamic elasticity modulus is negatively correlated with the freeze-thaw cycles and impact number. Furthermore, CT scanning shows a decrease in crack size and density as the freeze-thaw cycles increase.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Materials Science, Multidisciplinary
Seulbi Lee, Jaewoong Kim, Jungho Choe, Seong-Woong Kim, Jae-Keun Hong, Yoon Suk Choi
Summary: The crack formation mechanisms of Ti-48Al-2Cr-2Nb single tracks processed by laser powder bed fusion were investigated. Different crack patterns and formation mechanisms were observed under different laser processing conditions.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Bohan Wang, Li Cheng, Dongchun Li
Summary: Ultrasonic fatigue tests were conducted on TC4 titanium alloy specimens obtained by different forging processes, showing that they had different S-N curve shapes and no traditional fatigue limit. Among them, bimodal I exhibited the best comprehensive fatigue performance. SEM analysis revealed that fatigue cracks originated from surface or subsurface facets, indicating a transgranular quasi-cleavage fracture mechanism. EDS analysis showed that these facets were formed by the cleavage of primary alpha grains, and fatigue cracks originated from the preferred textures of primary alpha grains, rather than their clusters. The reasons for better equiaxed high-cycle-fatigue properties and better bimodal ultra-high-cycle-fatigue properties were analyzed from a microstructure perspective. Additionally, a fatigue life prediction for bimodal I based on energy was completed, showing good agreement with experimental data.
Article
Engineering, Mechanical
Bohan Wang, Li Cheng, Dongchun Li
Summary: This study investigated TC4 titanium alloy with different laser shock peening treatments using three-point bending ultrasonic fatigue tests. The results showed that the HCF properties of the alloy improved, while the VHCF properties deteriorated after a certain level of laser shock peening treatment. Further analysis revealed that the shift of the crack origin zone and the combined effect of residual compressive stress and surface nanocrystals played important roles in fatigue strengthening, whereas excessive grain refinement and subsurface failure mechanism weakened the fatigue properties.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Crystallography
Baohua Nie, Yu Song, Xianyi Huang, Haiying Qi, Zihua Zhao, Dongchu Chen
Summary: In this paper, the low cycle fatigue (LCF) behaviors of TC21 alloy with a bi-lamellar basketweave microstructure were investigated. The cyclic stress-strain as well as the strain-life equations were obtained. The fatigue life decreased significantly with an increasing total strain, and the cyclic softening behavior was interpreted by cyclic back stress and friction stress.
Editorial Material
Engineering, Mechanical
Andrey P. Jivkov, James Marrow, Andrey Shanyavskiy
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Engineering, Mechanical
Andrey A. Shanyayskiy, Alexey P. Soldatenkov
Summary: This paper analyzes the metal fatigue behavior based on the multi-scale description of damage accumulation processes, considering the governing mechanisms peculiar to each scale level. The transitions between scales gradually occur within the ranges with bimodal distribution of fatigue life.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Mechanical
Andrey A. Shanyavskiy, Aleksey P. Soldatenkov
Summary: This study analyzes the process of fatigue spalling in ball bearing rings with durability exceeding 10^8 cycles under in-service loading conditions using fractography and prepared slices. It is found that cracks originate from carbides or permissible inclusions in the bearing steel. Similar to the very-high-cycle fatigue regime, cracks develop with elliptical fish-eye formation. The step-by-step demonstration of subsequent crack growth and discussion of crack branching under mixed-mode I + II + III mechanisms is also presented.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Chemistry, Physical
Dongtong Yang, Sen Tang, Yongtao Hu, Alexander Nikitin, Qingyuan Wang, Yongjie Liu, Lang Li, Chao He, Yan Li, Bo Xu, Chong Wang
Summary: In this work, a novel model of ultrasonic fatigue test was developed to simulate the very high cycle fatigue failure of in-service components. The model successfully tested thin-wall material in bending at an accelerated frequency, with the sample resonating at 20kHz. The advantage of the second-order flexural vibration allowed the gauge section of the sample to be in a pure bending condition, reducing complex stress conditions. Combining constraint and loading contact reduced heating from ultrasonic frequency friction. Strain gauge and deflection angle methods verified stress amplitude control, and fractography observation confirmed the similarity between the novel model and conventional bending test.
Article
Engineering, Mechanical
Andrey Shanyavskiy, Ilia Nikitin, Alexander Nikitin
Summary: This paper presents an in-service fatigue fracture analysis of the first stage low-pressure compressor disk of the aircraft engines D30KU-154. It is found that the crack initiation in the rim part of the disk is caused by high frequency loading, while the total fatigue lifetime is determined by the simultaneous action of low amplitude loading and high amplitude loading.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Mechanical
Andrey A. Shanyavskiy, Alexey P. Soldatenkov
Summary: The in-service fatigue fracture mechanism of titanium alloy fan disk is analyzed through complex metallophysical research, with the crack path consisting of facetted pattern relief and striations on the fracture surface. The equivalent stress for different crack sizes is estimated based on the measurement results of striation spacing. The analysis of the aero-engine's schematized flight loading cycle helps determine the number of damaging-loading cycles per flight, while evaluating the inspection interval for reliable crack detection in the disk. The study demonstrates that the in-service durability of the fan disk can exceed 15,000 flights without damage.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Mechanics
I. S. Nikitin, N. G. Burago, A. D. Nikitin
Summary: Based on a previously suggested multimode two-criterion model of fatigue fracture, a method is proposed to calculate the origin and development of narrow localized damage zones in structural elements for various modes of cyclic loading. The method is applied to assess the durability of an aircraft gas turbine engine compressor disk and to study fatigue fracture in an experimental sample under high-frequency torsional vibrations.
MECHANICS OF SOLIDS
(2022)
Article
Multidisciplinary Sciences
Alexander D. Nikitin, Pavel S. Shesterkin, Sergey S. Lopatin
Summary: This paper investigates the fatigue failure problem of two-phase titanium alloy VT3-1 under high-frequency cyclic loading. The samples used for the experiments were taken from the compressor disk of the D30-Ku aviation engine installed on Tupolev Tu-154 planes. The loading was carried out through repeated alternating displacements of small amplitude at 20 kHz, coinciding with the first harmonic of longitudinal elastic vibrations of the sample. The analysis of fracture surfaces shows that subsurface fracture is predominant. The study also identifies the elements of microstructure associated with crack nucleation in the fatigue nucleation areas. The findings of this study can be applied in interpreting the fracture scenarios of structural elements during operation, and increasing the lifespan of products under similar loads can be achieved through the use of damping layers or tapes.
SN APPLIED SCIENCES
(2023)
Article
Engineering, Multidisciplinary
Arseny Babaytsev, Alexander Nikitin, Andrey Ripetskiy
Summary: This paper focuses on the VHCF properties of aluminum alloys produced using two different technological procedures. The results show that the VHCF properties of the hot-rolled D16T alloy are more than two times higher than those of the SLM AlSi10Mg alloy, despite the comparable quasi-static tensile properties. Fractographic analysis of the fracture surfaces explains the difference in fatigue properties.
Article
Mechanics
E. Naydenkin, A. P. Soldatenkov, I. P. Mishin, V. A. Oborin, A. A. Shanyavskiy
Summary: The fracture behavior of VT22 titanium alloy produced by radial shear rolling and subsequent aging was studied in very high cycle fatigue tests with ultrasonic vibration frequency. The processing significantly increased the static and fatigue strengths of the alloy. Fatigue crack initiation in the very high cycle fatigue region is associated with the formation of a fracture facet with higher local concentration of interstitial impurities.
PHYSICAL MESOMECHANICS
(2021)
Article
Mechanics
A. A. Shanyavskiy, A. D. Nikitin, T. Palin-Luc
Summary: The paper provides a fractographic analysis of fatigue cracking in D16T aluminum alloy under very high cycle fatigue at a frequency of 20 kHz. The analysis shows that cracks develop on and beneath the material's surface through intergranular or transgranular fracture, with a cascade of oriented and misoriented dimples forming along the main crack.
PHYSICAL MESOMECHANICS
(2021)