Pub Date : 2025-01-09DOI: 10.1016/j.ijfatigue.2025.108812
Min Zhan, Xue Li, Hai Xiong, Xinglin Yang, Yao Chen, Yongjie Liu, Chong Wang, Lang Li, Bing Xue, Yongbo Li, Qingyuan Wang, Chao He
This study examines the impact of ultrasonic peening treatment (UPT) on the very high cycle fatigue resistance of extruded Mg-Gd-Zn-Zr alloy. The findings reveal a significant alteration in crack initiation sites following UPT. The plastic deformation of the surface layer, residual stress, and the vacuum environment induced by the inward movement of the initiation site collectively contribute to an extended fatigue life of the specimen. By establishing a parameter M that elucidates the competitive relationship between subsurface and internal crack initiation, an evaluation model for crack initiation location post-UPT was obtained. Furthermore, by integrating the principle governing the formation of inclined fine granular area (FGA) morphology at the initiation site with the Paris law, a post-failure life analysis model based on the FGA initiation mode was developed.
{"title":"Effect of ultrasonic peening treatment on the crack initiation behavior of extruded Mg-Gd-Zn-Zr alloys under very high cycle regime","authors":"Min Zhan, Xue Li, Hai Xiong, Xinglin Yang, Yao Chen, Yongjie Liu, Chong Wang, Lang Li, Bing Xue, Yongbo Li, Qingyuan Wang, Chao He","doi":"10.1016/j.ijfatigue.2025.108812","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108812","url":null,"abstract":"This study examines the impact of ultrasonic peening treatment (UPT) on the very high cycle fatigue resistance of extruded Mg-Gd-Zn-Zr alloy. The findings reveal a significant alteration in crack initiation sites following UPT. The plastic deformation of the surface layer, residual stress, and the vacuum environment induced by the inward movement of the initiation site collectively contribute to an extended fatigue life of the specimen. By establishing a parameter M that elucidates the competitive relationship between subsurface and internal crack initiation, an evaluation model for crack initiation location post-UPT was obtained. Furthermore, by integrating the principle governing the formation of inclined fine granular area (FGA) morphology at the initiation site with the Paris law, a post-failure life analysis model based on the FGA initiation mode was developed.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"49 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.ijfatigue.2025.108811
Hongzhuang Zhang, Changyou Li, Shujie Cao, Ivan Sergeichev, Guian Qian
Side surface quality is a critical concern in the fatigue performance of laser powder bed fused (PBF-LB) components. Increasing contour passes with customized parameters along sample edge can tune side surface/subsurface quality and thereby enhance fatigue resistance. This study critically evaluates the surface and subsurface characteristics resulting from varying contour parameters and their impact on the fatigue performance of PBF-LB 304L steel through multiple detailed characterizations. The fatigue damage mechanisms for varying contour parameters are investigated through fatigue fractography, temperature field analysis, and microstructural evolution. Results indicate that optimal contour parameters differed from infill parameters due to the energy absorption from powder fusion and solidification remelting. The contour defects, including spherical vapor cavities and irregular lack-of-fusion (LoF) defects resulting from inappropriate parameters, significantly degrade fatigue lifetime due to their high-stress concentration factors. Appropriate contour parameters (approximately 300 J/mm3 in energy density) can minimize defect content while simultaneously enhancing microstructural heterogeneity in the contour region. The identified physical mechanisms of defect formation and fatigue damage will assist in designing and optimizing contour process for enhancing fatigue performance.
{"title":"Enhancing fatigue performance of laser powder bed fused metals through controlling contour parameters and structures","authors":"Hongzhuang Zhang, Changyou Li, Shujie Cao, Ivan Sergeichev, Guian Qian","doi":"10.1016/j.ijfatigue.2025.108811","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108811","url":null,"abstract":"Side surface quality is a critical concern in the fatigue performance of laser powder bed fused (PBF-LB) components. Increasing contour passes with customized parameters along sample edge can tune side surface/subsurface quality and thereby enhance fatigue resistance. This study critically evaluates the surface and subsurface characteristics resulting from varying contour parameters and their impact on the fatigue performance of PBF-LB 304L steel through multiple detailed characterizations. The fatigue damage mechanisms for varying contour parameters are investigated through fatigue fractography, temperature field analysis, and microstructural evolution. Results indicate that optimal contour parameters differed from infill parameters due to the energy absorption from powder fusion and solidification remelting. The contour defects, including spherical vapor cavities and irregular lack-of-fusion (LoF) defects resulting from inappropriate parameters, significantly degrade fatigue lifetime due to their high-stress concentration factors. Appropriate contour parameters (approximately 300 J/mm<ce:sup loc=\"post\">3</ce:sup> in energy density) can minimize defect content while simultaneously enhancing microstructural heterogeneity in the contour region. The identified physical mechanisms of defect formation and fatigue damage will assist in designing and optimizing contour process for enhancing fatigue performance.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"10 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-06DOI: 10.1016/j.ijfatigue.2024.108800
Michal Bartošák, Vladimír Mára, Eliška Galčíková, Michal Slaný, Miroslav Španiel, Ladislav Poczklán, Ivo Šulák
In this article, strain-controlled Low-Cycle Fatigue (LCF) and fatigue-creep tests were conducted on COST FB2, a boron-added 9% Cr martensitic stainless steel, at 600°C. LCF tests were performed with a mechanical strain rate of 1×10−3/s, while the fatigue-creep tests involved either tensile or compressive strain dwells lasting 600 s. Both the LCF and fatigue-creep tests revealed cyclic softening behaviour, with the magnitude of relaxed stress decreasing with cycles in the fatigue-creep tests. This softening was associated with the coarsening of the laths and subgrains and a reduction in dislocation density, both of which were more pronounced for LCF loading at higher strain amplitudes and during fatigue-creep loading. Investigations into the damage mechanisms identified environmentally assisted transgranular cracking as the predominant failure mode, with the severity of oxidation-induced cracking increasing with higher applied strain amplitudes or during fatigue-creep loading with compressive dwell, while cracking was suppressed during tests with tensile strain dwell. Finally, a damage model combining the strain-life approach with a time-dependent damage term was proposed to effectively predict the reduction in lifetime during fatigue-creep tests compared to continuous LCF cycling.
{"title":"Isothermal low-cycle fatigue and fatigue-creep behaviour of boron-added 9% Cr martensitic stainless steel at 600°C","authors":"Michal Bartošák, Vladimír Mára, Eliška Galčíková, Michal Slaný, Miroslav Španiel, Ladislav Poczklán, Ivo Šulák","doi":"10.1016/j.ijfatigue.2024.108800","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2024.108800","url":null,"abstract":"In this article, strain-controlled Low-Cycle Fatigue (LCF) and fatigue-creep tests were conducted on COST FB2, a boron-added 9% Cr martensitic stainless steel, at 600°C. LCF tests were performed with a mechanical strain rate of <mml:math altimg=\"si1.svg\" display=\"inline\"><mml:mrow><mml:mn>1</mml:mn><mml:mo linebreak=\"goodbreak\" linebreakstyle=\"after\">×</mml:mo><mml:mn>1</mml:mn><mml:msup><mml:mrow><mml:mn>0</mml:mn></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>3</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math>/s, while the fatigue-creep tests involved either tensile or compressive strain dwells lasting 600 s. Both the LCF and fatigue-creep tests revealed cyclic softening behaviour, with the magnitude of relaxed stress decreasing with cycles in the fatigue-creep tests. This softening was associated with the coarsening of the laths and subgrains and a reduction in dislocation density, both of which were more pronounced for LCF loading at higher strain amplitudes and during fatigue-creep loading. Investigations into the damage mechanisms identified environmentally assisted transgranular cracking as the predominant failure mode, with the severity of oxidation-induced cracking increasing with higher applied strain amplitudes or during fatigue-creep loading with compressive dwell, while cracking was suppressed during tests with tensile strain dwell. Finally, a damage model combining the strain-life approach with a time-dependent damage term was proposed to effectively predict the reduction in lifetime during fatigue-creep tests compared to continuous LCF cycling.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"41 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-04DOI: 10.1016/j.ijfatigue.2025.108808
Yanli Lu, Liyuan Hu, Ting Li, Gang Ran, Xiaowei Yi, Yukun Sun, Zhenyang Kong, Kuangshi Yan, Rui Hu, Hong Wang
Threaded components like bolts and studs, are prone to fatigue failures due to high stress concentration. GH4169 superalloy widely used in the aerospace field has excellent mechanical properties in high temperature environment and is ideal for high strength thread fasteners. In this study, the thread warm rolling process is developed to prepare GH4169 studs samples with enhanced fatigue performance. Firstly, the configuration of the rolling apparatus is introduced and described. Then, thread forming experiments are conducted on GH4169 matrix by use of the thread warm rolling process and traditional thread turning process respectively. The fatigue performance and mechanical properties of these formed studs are evaluated. Compared to the turning process, surface finish of thread root is further improved from Ra 0.26 to Ra 0.13, and increased microhardness distributed in the severe plastic deformation (SPD) layer are achieved for thread warm rolling process. The warm rolling process induces the SPD layer depth of approximately 80–100 μm at the thread root, significantly enhancing mechanical properties here and improving fatigue performance of overall parts. High cycle fatigue tests demonstrate that GH4169 studs formed by warm rolling process exhibit a fatigue life about 25 times greater than those formed by turning process.
{"title":"High cycle fatigue performance and corresponding fracture behaviors of GH4169 studs formed by thread warm rolling process","authors":"Yanli Lu, Liyuan Hu, Ting Li, Gang Ran, Xiaowei Yi, Yukun Sun, Zhenyang Kong, Kuangshi Yan, Rui Hu, Hong Wang","doi":"10.1016/j.ijfatigue.2025.108808","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108808","url":null,"abstract":"Threaded components like bolts and studs, are prone to fatigue failures due to high stress concentration. GH4169 superalloy widely used in the aerospace field has excellent mechanical properties in high temperature environment and is ideal for high strength thread fasteners. In this study, the thread warm rolling process is developed to prepare GH4169 studs samples with enhanced fatigue performance. Firstly, the configuration of the rolling apparatus is introduced and described. Then, thread forming experiments are conducted on GH4169 matrix by use of the thread warm rolling process and traditional thread turning process respectively. The fatigue performance and mechanical properties of these formed studs are evaluated. Compared to the turning process, surface finish of thread root is further improved from R<ce:inf loc=\"post\">a</ce:inf> 0.26 to R<ce:inf loc=\"post\">a</ce:inf> 0.13, and increased microhardness distributed in the severe plastic deformation (SPD) layer are achieved for thread warm rolling process. The warm rolling process induces the SPD layer depth of approximately 80–100 μm at the thread root, significantly enhancing mechanical properties here and improving fatigue performance of overall parts. High cycle fatigue tests demonstrate that GH4169 studs formed by warm rolling process exhibit a fatigue life about 25 times greater than those formed by turning process.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"21 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbide-free bainitic microstructures with different morphologies were obtained by designing different cooling rates in medium-carbon bainitic steel, and the effect of undercooled austenite cooling rate on the low cycle fatigue (LCF) properties of austempering bainitic steels was systematically investigated. The results show that with the reduction of the cooling rate, the bainitic ferrite laths are coarsened, the content of retained austenite is reduced, and the proportion of filmy retained austenite is increased. The samples with a cooling rate of 30 °C/s at low strain amplitude possessed higher fatigue life, while the samples with a cooling rate of 0.3 °C/s at high strain amplitude exhibited higher fatigue life. This is because the phase transformation induced plasticity (TRIP) effect at low strain amplitude improves the samples’ plastic deformation resistance. In contrast, the brittle martensite produced by the TRIP effect at high strain amplitude is more likely to provide a crack propagation path.
{"title":"Effect of undercooled austenite cooling rate on the low cycle fatigue properties of an austempering bainitic steel","authors":"Yingnan Li, Yu Zhang, Xiaoyan Long, Ranran Zhu, Wanshuai Wang, Yanguo Li, Zeliang Liu","doi":"10.1016/j.ijfatigue.2025.108809","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108809","url":null,"abstract":"Carbide-free bainitic microstructures with different morphologies were obtained by designing different cooling rates in medium-carbon bainitic steel, and the effect of undercooled austenite cooling rate on the low cycle fatigue (LCF) properties of austempering bainitic steels was systematically investigated. The results show that with the reduction of the cooling rate, the bainitic ferrite laths are coarsened, the content of retained austenite is reduced, and the proportion of filmy retained austenite is increased. The samples with a cooling rate of 30 °C/s at low strain amplitude possessed higher fatigue life, while the samples with a cooling rate of 0.3 °C/s at high strain amplitude exhibited higher fatigue life. This is because the phase transformation induced plasticity (TRIP) effect at low strain amplitude improves the samples’ plastic deformation resistance. In contrast, the brittle martensite produced by the TRIP effect at high strain amplitude is more likely to provide a crack propagation path.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"45 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975478","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study explores the fatigue behavior of prestressed CFRP-reinforced concrete (RC) beams in subtropical environments, addressing the gap in understanding their long-term performance under natural exposure. Five specimens were subjected to one year of natural exposure under sustained load conditions before fatigue testing. During the exposure period, the strain on the CFRP laminate was monitored, and a decrease of 5.37% in prestress loss after exposing 300 days was observed. The digital image correlation (DIC) method was employed to capture the crack initiation and growth during the fatigue tests, with detailed analyses of crack growth rates, deflection evolution, and failure modes. Experimental results indicated that natural exposure accelerates fatigue crack growth compared to the results of the unexposed RC beams tested by this group. Moreover, the finite element model (FEM) was developed to account for CFRP-concrete interface degradation due to natural exposure and material nonlinearities, allowing for the determination of the J-integral of the main crack. Fatigue life prediction models, based on experimentally obtained crack growth rates and stress intensity factors (SIF) calculated using the J-integral, were derived. The predicted fatigue lives were within a 20% error margin of the experimental results, demonstrating the reliability of the proposed models.
{"title":"Investigation of fatigue behavior in prestressed CFRP reinforced RC beams exposed to natural subtropical environment","authors":"Yilin Wang, Ruonan Zhang, Wen Li, Peiyan Huang, Hangyue Cui, Pengyu Wei, Roman Wan-Wendner, Xinyan Guo","doi":"10.1016/j.ijfatigue.2024.108802","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2024.108802","url":null,"abstract":"This study explores the fatigue behavior of prestressed CFRP-reinforced concrete (RC) beams in subtropical environments, addressing the gap in understanding their long-term performance under natural exposure. Five specimens were subjected to one year of natural exposure under sustained load conditions before fatigue testing. During the exposure period, the strain on the CFRP laminate was monitored, and a decrease of 5.37% in prestress loss after exposing 300 days was observed. The digital image correlation (DIC) method was employed to capture the crack initiation and growth during the fatigue tests, with detailed analyses of crack growth rates, deflection evolution, and failure modes. Experimental results indicated that natural exposure accelerates fatigue crack growth compared to the results of the unexposed RC beams tested by this group. Moreover, the finite element model (FEM) was developed to account for CFRP-concrete interface degradation due to natural exposure and material nonlinearities, allowing for the determination of the J-integral of the main crack. Fatigue life prediction models, based on experimentally obtained crack growth rates and stress intensity factors (SIF) calculated using the J-integral, were derived. The predicted fatigue lives were within a 20% error margin of the experimental results, demonstrating the reliability of the proposed models.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"26 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-02DOI: 10.1016/j.ijfatigue.2025.108805
Hailing Chen, Shengci Li, Yupeng Ren, Yang Li, Tingting Dong, Yuzhen Li
This work assessed and discussed the thermo-mechanical fatigue (TMF) behavior and microstructural damage mechanism of H13 hot work die steel. The results showed that the TMF life decreased and cycle softening became more pronounced with increasing mechanical strain amplitude. Surface oxidation accelerated crack initiation and the texture components changed to a {112} < 111 > copper texture at 1.1 %. In addition, the strain amplitude influenced carbide precipitation and aggregation distribution, which caused local stress concentrations, and lattice distortion provided energy for carbide nucleation and growth.
{"title":"Thermo-mechanical fatigue behavior and damage mechanisms under different mechanical strain amplitudes in H13 steel","authors":"Hailing Chen, Shengci Li, Yupeng Ren, Yang Li, Tingting Dong, Yuzhen Li","doi":"10.1016/j.ijfatigue.2025.108805","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108805","url":null,"abstract":"This work assessed and discussed the thermo-mechanical fatigue (TMF) behavior and microstructural damage mechanism of H13 hot work die steel. The results showed that the TMF life decreased and cycle softening became more pronounced with increasing mechanical strain amplitude. Surface oxidation accelerated crack initiation and the texture components changed to a {112} < 111 > copper texture at 1.1 %. In addition, the strain amplitude influenced carbide precipitation and aggregation distribution, which caused local stress concentrations, and lattice distortion provided energy for carbide nucleation and growth.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"25 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-02DOI: 10.1016/j.ijfatigue.2024.108790
Changkai Wang, Yuting He, Teng Zhang, Tianyu Zhang, Jinhui Fu
This paper investigated the corrosion damage and fatigue fracture mechanisms of ZL114A cast aluminum alloy through laboratory pre-corrosion fatigue test conducted under simulated tropical marine humid-hot atmosphere. Additionally, based on the analysis results of surface casting defect equivalence and material damage mechanism, three types of fatigue life degradation models for this cast aluminum alloy after pre-corrosion were proposed. The results show that the primary corrosion damage modes of the material in the laboratory’s accelerated corrosion environment are corrosive pitting and intergranular corrosion because of the enriched Si phase in the grain boundary. The fatigue life of pre-corroded specimens exhibits three stages of degradation characterized by initial decline stage; horizontal stage; secondary decline stage, correlating with increasing corrosion time. The primary factors behind this phenomenon are hydrogen embrittlement and the competing effects of surface casting defects and intergranular corrosion on the initiation of fatigue cracks. The fitting results of the three types of pre-corrosion fatigue life degradation models are better than the traditional models.
{"title":"Life degradation and damage mechanism of ZL114A aluminum alloy under pre-corrosion fatigue in simulated tropical marine atmospheric environment","authors":"Changkai Wang, Yuting He, Teng Zhang, Tianyu Zhang, Jinhui Fu","doi":"10.1016/j.ijfatigue.2024.108790","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2024.108790","url":null,"abstract":"This paper investigated the corrosion damage and fatigue fracture mechanisms of ZL114A cast aluminum alloy through laboratory pre-corrosion fatigue test conducted under simulated tropical marine humid-hot atmosphere. Additionally, based on the analysis results of surface casting defect equivalence and material damage mechanism, three types of fatigue life degradation models for this cast aluminum alloy after pre-corrosion were proposed. The results show that the primary corrosion damage modes of the material in the laboratory’s accelerated corrosion environment are corrosive pitting and intergranular corrosion because of the enriched Si phase in the grain boundary. The fatigue life of pre-corroded specimens exhibits three stages of degradation characterized by initial decline stage; horizontal stage; secondary decline stage, correlating with increasing corrosion time. The primary factors behind this phenomenon are hydrogen embrittlement and the competing effects of surface casting defects and intergranular corrosion on the initiation of fatigue cracks. The fitting results of the three types of pre-corrosion fatigue life degradation models are better than the traditional models.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"1 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142929641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The accurate prediction of fatigue crack growth is essential for evaluating the service life of critical machine components and for conducting failure analysis. Traditional models often struggle to accurately capture the complex, non-linear relationships between the fatigue crack growth rate (da/dN) and the stress intensity factor range (ΔK), especially within the Paris regime. Additionally, the influence of the stress ratio (R) on the fatigue crack growth rate varies significantly across different materials, posing a challenge for existing predictive models. This study addresses these scientific gaps by leveraging the robust learning capabilities of machine learning algorithms to handle these non-linearities. Specifically, we compare the effectiveness of deep neural networks (DNN) and linear regression models in predicting fatigue crack growth rate (FCGR) across all three stages, using experimental data derived from compact-tension (CT) specimens made of high-carbon tempered martensitic steel subjected to cyclic loading at various R ratios in addition to existing literature data. The novelty of this work lies in its inclusion of high-carbon tempered martensitic steel, belonging to a class of brittle material, a class for which data on varying R ratios is scarce compared to more commonly studied ductile materials like relatively ductile steels, titanium and aluminium. The effect of R ratio on FCGR is more pronounced in brittle materials, as seen by the wider spacing of FCGR curves compared to ductile materials. This makes FCGR prediction at varying R ratios especially important. We found that models trained solely on literature data perform poorly. However, using experimental data from this material significantly improves prediction accuracy, highlighting the importance of such data for brittle materials. Conceding the fact that deep learning methods provide the best prediction, a broader set of independent variables have been incorporated in the same and hyperparameters have been optimized demonstrating high accuracy in predicting fatigue crack growth rates across different R ratios, thereby reducing reliance on extensive and costly experimental procedures. Our findings not only advance the understanding of fatigue crack growth in this specific steel but also offer a more generalizable approach for predicting crack growth in other materials with complex stress ratio behaviors.
{"title":"Prediction of sub-critical fatigue crack growth rate in a high-carbon tempered martensitic steel at varying R ratio: Experimental investigation and machine learning based modelling","authors":"Sudharm Rathore, Avanish Kumar, Anurag Kumar, Kushal Mishra, Aparna Singh","doi":"10.1016/j.ijfatigue.2025.108804","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108804","url":null,"abstract":"The accurate prediction of fatigue crack growth is essential for evaluating the service life of critical machine components and for conducting failure analysis. Traditional models often struggle to accurately capture the complex, non-linear relationships between the fatigue crack growth rate (da/dN) and the stress intensity factor range (ΔK), especially within the Paris regime. Additionally, the influence of the stress ratio (R) on the fatigue crack growth rate varies significantly across different materials, posing a challenge for existing predictive models. This study addresses these scientific gaps by leveraging the robust learning capabilities of machine learning algorithms to handle these non-linearities. Specifically, we compare the effectiveness of deep neural networks (DNN) and linear regression models in predicting fatigue crack growth rate (FCGR) across all three stages, using experimental data derived from compact-tension (CT) specimens made of high-carbon tempered martensitic steel subjected to cyclic loading at various R ratios in addition to existing literature data. The novelty of this work lies in its inclusion of high-carbon tempered martensitic steel, belonging to a class of brittle material, a class for which data on varying R ratios is scarce compared to more commonly studied ductile materials like relatively ductile steels, titanium and aluminium. The effect of R ratio on FCGR is more pronounced in brittle materials, as seen by the wider spacing of FCGR curves compared to ductile materials. This makes FCGR prediction at varying R ratios especially important. We found that models trained solely on literature data perform poorly. However, using experimental data from this material significantly improves prediction accuracy, highlighting the importance of such data for brittle materials. Conceding the fact that deep learning methods provide the best prediction, a broader set of independent variables have been incorporated in the same and hyperparameters have been optimized demonstrating high accuracy in predicting fatigue crack growth rates across different R ratios, thereby reducing reliance on extensive and costly experimental procedures. Our findings not only advance the understanding of fatigue crack growth in this specific steel but also offer a more generalizable approach for predicting crack growth in other materials with complex stress ratio behaviors.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"29 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The fatigue characteristics of a strain-localized material specimen with an inclined notch, subjected to cyclic tension–compression under plane strain conditions, have not been fully elucidated. An unloading elastic compliance test and electron backscattering diffraction analyses were conducted near a fatigue crack tip on inclined notched specimens of JIS-SM490YB hot-rolled steel. Crack extension caused a characteristic change in the local mean strain from zero to a positive value, corresponding to the transition from local plasticity induced by a notch to that induced by a fatigue crack. The sudden increase in local elastic compliance and negative crack opening load were the mechanical indicators of the damage accumulation mode of the fatigue crack extension mode-type.
{"title":"Transition of fatigue-crack extension mechanism on a hot rolled steel with an inclined notch under cyclic tension–compression and plane strain conditions","authors":"Bowen Chen, Shigeru Hamada, Takanori Kato, Taizo Makino, Hiroshi Noguchi","doi":"10.1016/j.ijfatigue.2025.108806","DOIUrl":"https://doi.org/10.1016/j.ijfatigue.2025.108806","url":null,"abstract":"The fatigue characteristics of a strain-localized material specimen with an inclined notch, subjected to cyclic tension–compression under plane strain conditions, have not been fully elucidated. An unloading elastic compliance test and electron backscattering diffraction analyses were conducted near a fatigue crack tip on inclined notched specimens of JIS-SM490YB hot-rolled steel. Crack extension caused a characteristic change in the local mean strain from zero to a positive value, corresponding to the transition from local plasticity induced by a notch to that induced by a fatigue crack. The sudden increase in local elastic compliance and negative crack opening load were the mechanical indicators of the damage accumulation mode of the fatigue crack extension mode-type.","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"41 1","pages":""},"PeriodicalIF":6.0,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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