Minjie Song , Yue Qiu , Boan Xu , Ping Jiang , Shaoning Geng , Yilin Wang , Jintian Zhao , Yun Hu
{"title":"Fatigue failure and grain refinement strengthening mechanism of aluminum alloy weld","authors":"Minjie Song , Yue Qiu , Boan Xu , Ping Jiang , Shaoning Geng , Yilin Wang , Jintian Zhao , Yun Hu","doi":"10.1016/j.ijfatigue.2025.108950","DOIUrl":"10.1016/j.ijfatigue.2025.108950","url":null,"abstract":"<div><div>A comprehensive understanding of fatigue failure and grain refinement strengthening mechanisms in aluminum alloy welds is crucial for improving their fatigue performance. This study proposes a novel macro–micro multiscale modeling method based on realistic microstructures and combines a dislocation-based crystal plasticity finite element model (CPFEM) with continuous fatigue damage theory. Through this approach, the fatigue crack propagation process and grain refinement strengthening mechanisms in laser-welded aluminum alloys are systematically investigated. The results reveal that fatigue crack propagation predominantly involves mixed fracture modes, with transgranular fracture being dominant and intergranular fracture secondary. High-stress regions at crack tips activate slip systems, significantly increasing cumulative slip and dislocation density, driving localized plastic deformation and promoting crack growth. Grain refinement enhances fatigue resistance through synergistic effects of grain boundary strengthening and dislocation strengthening. As grain size decreases, stress concentrations at crack tips are dispersed, broadening high-stress regions and enhancing crack resistance through grain boundary strengthening. Concurrently, grain boundaries hinder dislocation glide, leading to increased dislocation accumulation and interactions, which enhances resistance to crack propagation. Additionally, smaller grains lead to higher stored energy density, increasing energy dissipation and delaying crack growth. These findings provide valuable insights into fatigue failure mechanisms and practical strategies for enhancing the fatigue performance of aluminum alloy welds.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108950"},"PeriodicalIF":5.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716242","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}
Jie Yan, Zicong Cao, Weizheng Zhang, Shuang Jin, Zhenyao Guo, Yanpeng Yuan, Haoyu Ma
{"title":"Research on the microscopic characteristics of low-cycle-fatigue and creep coupling in cast aluminum alloys for cylinder heads","authors":"Jie Yan, Zicong Cao, Weizheng Zhang, Shuang Jin, Zhenyao Guo, Yanpeng Yuan, Haoyu Ma","doi":"10.1016/j.ijfatigue.2025.108952","DOIUrl":"10.1016/j.ijfatigue.2025.108952","url":null,"abstract":"<div><div>As one of the most structurally complex components in diesel engines, the cylinder head is subjected to increasing thermal loads. This paper investigates the microscopic characteristics of fracture morphology in cast aluminum alloy materials for cylinder heads under high-temperature low-cycle-fatigue-creep (LCFC) coupling conditions. The study explores the effect of creep on the microscopic evolution of the material’s microstructure, clarifies the fracture failure modes, and identifies the underlying causes. The results show that at 250 °C, the fracture surfaces in low-cycle-fatigue (LCF) tests mainly exhibit brittle fracture characteristics. As the temperature increases, the fracture gradually transitions from brittle to ductile. Due to the influence of creep, the fracture surfaces in LCFC tests already show ductile fracture characteristics at 250 °C. Microscopic observations reveal that the reasons for the more pronounced cyclic softening phenomenon in LCFC conditions are attributed to creep’s effects on dislocation annihilation, dislocation rearrangement, and the coarsening and dissolution of precipitates. Two fracture modes, defect-induced fracture and Si-phase fracture, are proposed. Observations indicate that high-temperature creep can cause the eutectic Si structures within the material to fracture more easily, thereby altering the fracture mode.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108952"},"PeriodicalIF":5.7,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724879","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}
Qingfan Xie , Hongxia Zhang , Shubang Wang , Zhifeng Yan
{"title":"Research on the internal and external synergistic strengthening mechanism of fatigue performance of austenitic stainless steel","authors":"Qingfan Xie , Hongxia Zhang , Shubang Wang , Zhifeng Yan","doi":"10.1016/j.ijfatigue.2025.108948","DOIUrl":"10.1016/j.ijfatigue.2025.108948","url":null,"abstract":"<div><div>In this study, the effects of the synergy between pre-tensioning and surface mechanical rolling on the microstructure and fatigue performance of 304 stainless steel were discussed. The 304 stainless steel was subjected to pre-tensioning treatment, and a transformation in the microstructure was observed, with refinement of the grain size accompanied by the occurrence of martensitic transformation, and a quantitative analysis of the martensitic phase change was conducted. The yield strength of 304 stainless steel rises with pre-tensioning, equalizing with tensile strength after 50 % pre-tensioning. The hardness of the specimen was increased after pre-tensioning. After surface mechanical rolling, the hardness values exhibited a gradation decreasing progressively from the surface to the subsurface and then to the center. Based on the rotating bending fatigue test, under the combined effects of 50 % pre-tensioning and surface mechanical rolling, the fatigue limit of the specimen was increased from 365 MPa to 940 MPa, representing an improvement of 157.53 %. Based on the analysis of the properties and microstructure of processed 304 stainless steel, the effects of the pre-tensioning process and surface mechanical rolling on the material are discussed. The mechanism of the process enhancing fatigue properties through the combined effect of pre-tensioning and surface mechanical rolling is discussed.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108948"},"PeriodicalIF":5.7,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678345","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}
A. Panerai, L.M. Martulli, A. Bernasconi, M. Carboni
{"title":"Advanced strain-based approaches for monitoring crack tip position in adhesively bonded joints subjected to mixed mode fatigue loading","authors":"A. Panerai, L.M. Martulli, A. Bernasconi, M. Carboni","doi":"10.1016/j.ijfatigue.2025.108946","DOIUrl":"10.1016/j.ijfatigue.2025.108946","url":null,"abstract":"<div><div>In most structures, adhesive joints are subject to a combination of mode I (opening) and mode II (in-plane shear) loading. Most of the current research on adhesive joints, however, focuses on pure modes. The resistance of adhesive joints to fracture is investigated through crack propagation tests, during which the crack length must be measured with high accuracy. Visual Testing is usually employed, because it is the standardized method, but it may be uncertain. Other techniques, such as Digital Image Correlation, may be employed to increase accuracy. In this work, a Cracked Lap Shear specimen is used to study crack monitoring under mixed mode loading. Two techniques were used to measure crack length: Digital Image Correlation and distributed backface strain monitoring using Optical Backscatter Reflectometry (OBR) fibre sensors. Both techniques were shown to provide reliably accurate measurements. In the first part of this work, a method is presented which is able to accurately measure the crack length using Digital Image Correlation without needing to rely on Visual Testing; additionally, the deformation of the adhesive layer was investigated, which can provide an insight into the adhesive’s behaviour under mixed mode loading. Then, it is shown that accurate crack length measurements may be obtained with distributed backface strain monitoring by optical fibres applied to either side of the joint. Given fibre sensors’ low profile and ease of installation, OBR’s ability to measure crack growth offers significant potential for in-service monitoring of bonded structures.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108946"},"PeriodicalIF":5.7,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716241","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}
{"title":"Low-cycle fatigue bond behaviour between sand-coated hybrid FRP tubes and sustainable seawater sea sand concrete","authors":"Jivan Subedi , Anastasios Petsalis , Milad Bazli , Ali Rajabipour , Reza Hassanli , Milad Shakiba","doi":"10.1016/j.ijfatigue.2025.108947","DOIUrl":"10.1016/j.ijfatigue.2025.108947","url":null,"abstract":"<div><div>This study examines the bond behaviour of sand-coated hybrid Fibre Reinforced Polymer (HFRP) tubes filled with seawater sea sand concrete (SWSSC) under static and cyclic axial loads through push-out tests. The HFRP tubes, manufactured from glass and carbon fibre-reinforced polymer composites, were tested under incrementally increasing cyclic loading. Four distinct displacement-controlled loading regimes were explored, with cycles repeated 1, 3, 5, and 10 times for each specified displacement. The results showed that bond strength and energy dissipation capacity decrease with increased cycle repetitions due to cumulative interface degradation, while static tests indicated higher bond strengths at smaller displacements. ANOVA analysis confirmed that although significant differences in bond strength were observed with varying cycle repetitions, the displacements corresponding to maximum bond strength remained statistically similar. Quantitatively, the bond strength decreased from an average of 2.35 MPa in the single-cycle regime to approximately 1.89 MPa in the 10-cycle regime (a reduction of around 19 %). At lower cyclic repetitions (1 and 3 cycles), failure was primarily characterised by partial debonding at the interfaces between the sand coating and both the SWSSC and the HFRP tube. With increasing cycle repetitions (5 and 10 cycles), the bond damage significantly escalated, and a shift to complete coating detachment occurred. The damage mechanism evolved from interface failure within the SWSSC/HFRP–sand coating layers to complete separation of the composite layers from the SWSSC. These results show how cumulative damage effectively undermines the interface bonding between the components, emphasising the relevance of considering the number of cycles in evaluating composite durability under real-world conditions. These findings can improve the design and durability assessment of HFRP-concrete composite structures, particularly in environments subjected to repetitive loading conditions.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108947"},"PeriodicalIF":5.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jindi Zhou , Kai Huang , Hao Lu , Zhongyu Wang , Xiaojian Han , Hongsen Liu , Licheng Guo
{"title":"A novel insight into fatigue damage mechanism of plain-woven composites using 3D-DIC","authors":"Jindi Zhou , Kai Huang , Hao Lu , Zhongyu Wang , Xiaojian Han , Hongsen Liu , Licheng Guo","doi":"10.1016/j.ijfatigue.2025.108945","DOIUrl":"10.1016/j.ijfatigue.2025.108945","url":null,"abstract":"<div><div>Composite materials are known for their excellent mechanical properties, but their fatigue damage behavior is complex and challenging to characterize. In order to investigate the fatigue behavior of carbon fiber/epoxy plain-woven composites, a novel testing method is proposed by integrating low-frequency cycles into regular fatigue cycles, enabling precise capture of strain field evolution during fatigue by 3D digital image correlation (3D-DIC). Quantitative characterization methods for typical damage modes are established by combining displacement and strain data from 3D-DIC. The results of fatigue experiments reveal the fatigue damage process for the first time of plain-woven composites, which consists of five stages: initial weft yarn cracking, warp-weft separation, interlayer delamination, reduced load transfer, and final failure. These findings enhance the understanding of fatigue behavior in woven composites, and are of great significance for their anti-fatigue design.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108945"},"PeriodicalIF":5.7,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678347","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}
{"title":"Comparison of low cycle fatigue data of X52 pipeline steel in air and gaseous hydrogen using conventional and hollow specimen","authors":"Thorsten Michler, Heiner Oesterlin, Carl Fischer","doi":"10.1016/j.ijfatigue.2025.108939","DOIUrl":"10.1016/j.ijfatigue.2025.108939","url":null,"abstract":"<div><div>The present work compares low cycle fatigue results in high pressure gaseous hydrogen and in ambient air using hollow (HS) and conventional specimens (CS). For the given X52 pipeline steel and test conditions (ambient air and 20 MPa hydrogen gas pressure, R<sub>ε</sub> = 0.1, f = 0.1 Hz), the presence of a borehole had no significant influence on the elastic–plastic deformation behavior of the HS compared to CS. Test results in ambient air were comparable. Data for CS tested in hydrogen gas was not available but was approximated by fatigue crack growth results from the open literature at comparable test conditions. Hydrogen-assisted reduction of fatigue life was sufficiently similar in both, HS and CS. For the HS tested in H<sub>2</sub> gas, fatigue cracks always initiated at the inner bore gauge surface.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108939"},"PeriodicalIF":5.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rui F. Martins , Ricardo Branco , José Camacho , Wojciech Macek , Zbigniew Marciniak , António Silva , Cândida Malça
{"title":"The influence of printing strategies on the fatigue crack growth behaviour of an additively manufactured Ti6Al4V Grade 23 titanium alloy","authors":"Rui F. Martins , Ricardo Branco , José Camacho , Wojciech Macek , Zbigniew Marciniak , António Silva , Cândida Malça","doi":"10.1016/j.ijfatigue.2025.108942","DOIUrl":"10.1016/j.ijfatigue.2025.108942","url":null,"abstract":"<div><div>The selective laser melting (SLM) process, a type of laser powder-bed fusion (LPBF) in additive manufacturing (AM), uses a high-power density laser to melt metallic powders. This study involved 3D printing Compact Tension (CT) specimens from titanium alloy Ti6Al4V, known for its rigidity, corrosion resistance, and biocompatibility, making it suitable for aerospace and medical applications.</div><div>To predict fatigue life, it is essential to assess fatigue crack growth rates (FCGR) in the presence of cracks. This investigation tested three printing strategies − transversal, longitudinal, and cross − under constant amplitude loading (R = 0.2) and compared the results with reference titanium alloys. Scanning electron microscopy (SEM) was used to analyze the fracture surfaces.</div><div>The results indicated that the as-built AM transversal CT specimens (R = 0.2) had superior FCGR compared to the longitudinal and cross specimens, closely matching those of SLM-produced Ti6Al4V heat-treated at 670 °C (R = 0.05). The transverse deposition mode yielded the best performance, with fracture surfaces exhibiting mainly transgranular propagation. In addition, fracture surface topography measurements showed a strong correlation with fatigue life, particularly the relationship between the mean depth of furrows and the number of cycles to failure.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108942"},"PeriodicalIF":5.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644060","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}
Yifei Yu , Wenchun Jang , Bingying Wang , Fuxiao Hu , Hongge Li , Zhiqiang Ding
{"title":"Notch structural stress theory: Part Ⅲ surface roughness effect on fatigue lives","authors":"Yifei Yu , Wenchun Jang , Bingying Wang , Fuxiao Hu , Hongge Li , Zhiqiang Ding","doi":"10.1016/j.ijfatigue.2025.108938","DOIUrl":"10.1016/j.ijfatigue.2025.108938","url":null,"abstract":"<div><div>The dispersion of fatigue data is largely attributed to the effects of surface roughness, which are often overlooked in current structural fatigue assessment methodologies. This study examines the influence of surface roughness on the fatigue life of aluminum alloy notched specimens using our previously established Theory of Notch Structural Stress (TNSS). Results demonstrate a strong correlation between the <em>IR</em> describing the influence from structure factors and <em>p<sub>i</sub></em> related to fatigue life prediction, when the maximum valley depth of the surface profile is employed as an appropriate parameter. Consequently, TNSS enables accurate fatigue life predictions across varying notch geometries and surface roughness conditions.</div><div>While surface roughness is commonly regarded as having minimal impact on fatigue performance in the presence of sharp notches, the definition of notch sharpness remains ambiguous. In respect of this point, TNSS quantifies roughness sensitivity across different notch forms within a unified physical framework, providing a generalized understanding of roughness effects on fatigue lives without disregarding the crack initiation stage.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108938"},"PeriodicalIF":5.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644061","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}
Hongguang Zhou , Ziming Wang , Yunpeng Zhao , Congjie Kang , Xiaohui Yu
{"title":"A novel neural network model considering cyclic loading condition for low-cycle fatigue life prediction","authors":"Hongguang Zhou , Ziming Wang , Yunpeng Zhao , Congjie Kang , Xiaohui Yu","doi":"10.1016/j.ijfatigue.2025.108943","DOIUrl":"10.1016/j.ijfatigue.2025.108943","url":null,"abstract":"<div><div>Existing data driven low-cycle fatigue (LCF) life prediction models exhibit limited attention to the heterogeneity of input features and relatively insufficient consideration of cyclic loading condition. This study introduces a novel approach based on a long short-term memory parallel hierarchical neural network (LSTM-PHNN). Firstly, the input features are classified into three categories based on their physical significance and distribution characteristics: elemental parameters, microstructural property parameters, and loading parameters. Next, waveform features over a complete cycle are reconstructed for different loading parameters to characterize the impact of time-series cyclic loading condition on fatigue life. Finally, three predictive models were developed: a fully connected neural network (FCNN), a parallel hierarchical neural network (PHNN), and the proposed LSTM-PHNN model. Comparative analysis was conducted using the small sample LCF dataset of 316L stainless steel. The results show that the proposed LSTM-PHNN model outperforms both the FCNN and PHNN models,with almost all predictive data falling within a scatter band of 1.5 times and the prediction accuracy on the test set reaching 0.954. The above demonstrate that the LSTM-PHNN model provides a highly accurate and robust method for predicting LCF life with a small amount of experimental data.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"197 ","pages":"Article 108943"},"PeriodicalIF":5.7,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143678349","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}