Pub Date : 2026-01-14DOI: 10.1016/j.engfailanal.2026.110581
Pengfei Ma , Yangyang Zhang , Lichao Nie , Zhiqiang Li , Zhicheng Song , Yuancheng Li
Collapse is likely when long, deeply buried tunnels intersect water-rich fractured basalt. Single-method forecasting cannot resolve the spatial distribution of water-bearing structures or the progressive failure process. Using the Xianglu Mountain Tunnel as a case study, we propose a mechanism-analysis framework in which integrated geophysical prospecting provides priors for a Peridynamic (PD) numerical model. Specifically, Seismic ahead prospecting yields spatial distributions of elastic modulus, Poisson’s ratio, and density ahead of the face. Direct current resistivity delineates low-resistivity anomalies and, through an empirical resistivity–permeability relationship, enables quantitative inversion of the pre-excavation seepage field. These geophysical products are then injected as prior fields into a PD-based excavation–seepage failure model. The simulations indicate progressive damage of the confining rock layer (aquiclude) under multi-factor coupling until the damage zone coalesces and collapse occurs. Comparison with field observations shows close agreement in the predicted affected extent, demonstrating that the integrated approach explains collapse during excavation in water-rich basalt tunnels and provides a reliable pathway for advanced prevention and control of similar geohazards in deeply buried tunnels.
{"title":"Collapse mechanism of deep-buried long water-rich basalt tunnels based on integrated geophysical prospecting: A case study in Yunnan, China","authors":"Pengfei Ma , Yangyang Zhang , Lichao Nie , Zhiqiang Li , Zhicheng Song , Yuancheng Li","doi":"10.1016/j.engfailanal.2026.110581","DOIUrl":"10.1016/j.engfailanal.2026.110581","url":null,"abstract":"<div><div>Collapse is likely when long, deeply buried tunnels intersect water-rich fractured basalt. Single-method forecasting cannot resolve the spatial distribution of water-bearing structures or the progressive failure process. Using the Xianglu Mountain Tunnel as a case study, we propose a mechanism-analysis framework in which integrated geophysical prospecting provides priors for a Peridynamic (PD) numerical model. Specifically, Seismic ahead prospecting yields spatial distributions of elastic modulus, Poisson’s ratio, and density ahead of the face. Direct current resistivity delineates low-resistivity anomalies and, through an empirical resistivity–permeability relationship, enables quantitative inversion of the pre-excavation seepage field. These geophysical products are then injected as prior fields into a PD-based excavation–seepage failure model. The simulations indicate progressive damage of the confining rock layer (aquiclude) under multi-factor coupling until the damage zone coalesces and collapse occurs. Comparison with field observations shows close agreement in the predicted affected extent, demonstrating that the integrated approach explains collapse during excavation in water-rich basalt tunnels and provides a reliable pathway for advanced prevention and control of similar geohazards in deeply buried tunnels.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"187 ","pages":"Article 110581"},"PeriodicalIF":5.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.engfailanal.2026.110579
Jiaxin Lei , Yangyong Luoze , Haoyao Xia , Jianing Liu , Caiyou Zhao , Ping Wang
With the continuous increase in train operating speeds, rolling contact fatigue on rail surfaces has become a major concern, especially in welded regions where geometric irregularities and material mismatches intensify stress concentrations and accelerate crack growth. This study integrates ABAQUS and FRANC3D through a fracture-mechanics-based submodeling approach to simulate surface crack propagation in welded rails with realistic 3D weld geometry. The developed model clarifies how crack geometry and weld irregularities jointly affect fatigue behavior under rolling contact loads. The results indicate that surface cracks mainly propagate through a mixed Mode II–III shear mechanism. A 45° inclination angle represents the most critical propagation orientation. Increasing the surface crack length from 2 mm to 6 mm shortens fatigue life by 57.7%, while extending the crack length to 8 mm elevates the peak Mode III stress-intensity factor to 811 MPa, promoting inward growth. In the weld zone, the deeper crack front propagates faster, causing semicircular cracks to evolve into elongated ellipses. A strong interaction is observed between weld wavelength, depth and crack phase position: shorter wavelengths and deeper undulations markedly increase the Mode II stress-intensity factor, with the fastest propagation occurring at 3/8 of the weld wavelength—where fatigue life drops to 44% of that at 7/8 of the wavelength. The findings clarify the shear-dominated crack evolution mechanism and provide theoretical guidance for weld-grinding thresholds and fatigue-life assessment of welded rails in high-speed railway applications.
{"title":"Analysis of mechanical behavior and propagation mechanisms of rail cracks considering the influence of three-dimensional weld geometry","authors":"Jiaxin Lei , Yangyong Luoze , Haoyao Xia , Jianing Liu , Caiyou Zhao , Ping Wang","doi":"10.1016/j.engfailanal.2026.110579","DOIUrl":"10.1016/j.engfailanal.2026.110579","url":null,"abstract":"<div><div>With the continuous increase in train operating speeds, rolling contact fatigue on rail surfaces has become a major concern, especially in welded regions where geometric irregularities and material mismatches intensify stress concentrations and accelerate crack growth. This study integrates ABAQUS and FRANC3D through a fracture-mechanics-based submodeling approach to simulate surface crack propagation in welded rails with realistic 3D weld geometry. The developed model clarifies how crack geometry and weld irregularities jointly affect fatigue behavior under rolling contact loads. The results indicate that surface cracks mainly propagate through a mixed Mode II–III shear mechanism. A 45° inclination angle represents the most critical propagation orientation. Increasing the surface crack length from 2 mm to 6 mm shortens fatigue life by 57.7%, while extending the crack length to 8 mm elevates the peak Mode III stress-intensity factor to 811 MPa, promoting inward growth. In the weld zone, the deeper crack front propagates faster, causing semicircular cracks to evolve into elongated ellipses. A strong interaction is observed between weld wavelength, depth and crack phase position: shorter wavelengths and deeper undulations markedly increase the Mode II stress-intensity factor, with the fastest propagation occurring at 3/8 of the weld wavelength—where fatigue life drops to 44% of that at 7/8 of the wavelength. The findings clarify the shear-dominated crack evolution mechanism and provide theoretical guidance for weld-grinding thresholds and fatigue-life assessment of welded rails in high-speed railway applications.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"187 ","pages":"Article 110579"},"PeriodicalIF":5.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146001770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.engfailanal.2026.110582
Fanghuai Chen , Benkun Tan , Haitao Tang , Haiping Zhang , Yuan Luo , Xinhui Xiao , Yang Liu , Naiwei Lu
This paper presents an efficient predictive framework based on a random forest (RF) surrogate model for estimating fatigue crack propagation life in double-sided rib-to-deck (RD) welded joints in orthotropic steel decks (OSDs). A comprehensive training dataset for the RF surrogate model of stress intensity factor (SIF) was generated through extensive fatigue crack propagation simulations. The predictive accuracy of the RF surrogate model was rigorously validated, and SHAP-based feature analysis was employed to interpret the influence of input variables. The RF surrogate model was then used to estimate the fatigue life of the welded toe in double-sided RD welded joints, and the effects of initial crack geometry on fatigue life were investigated. The results indicate that the initial surface crack at the weld toe is a mode I-dominated mixed-mode crack and exhibits crack flattening during propagation. The RF surrogate model demonstrates high predictive accuracy for SIF, achieving high R2 values and low prediction errors across both training and validation datasets. SHAP analysis identifies applied stress as the primary influencer of SIF, with crack depth and half-length as secondary factors. Increases in initial crack depth and half-length significantly reduce fatigue crack propagation life. This study confirms the robustness of the RF model as a computationally efficient alternative to finite element methods (FEM), providing valuable insights for fatigue assessment and maintenance planning of OSDs.
{"title":"An interpretable random forest surrogate for rapid SIF prediction and fatigue life assessment of double-sided U-rib welds in orthotropic steel decks","authors":"Fanghuai Chen , Benkun Tan , Haitao Tang , Haiping Zhang , Yuan Luo , Xinhui Xiao , Yang Liu , Naiwei Lu","doi":"10.1016/j.engfailanal.2026.110582","DOIUrl":"10.1016/j.engfailanal.2026.110582","url":null,"abstract":"<div><div>This paper presents an efficient predictive framework based on a random forest (RF) surrogate model for estimating fatigue crack propagation life in double-sided rib-to-deck (RD) welded joints in orthotropic steel decks (OSDs). A comprehensive training dataset for the RF surrogate model of stress intensity factor (SIF) was generated through extensive fatigue crack propagation simulations. The predictive accuracy of the RF surrogate model was rigorously validated, and SHAP-based feature analysis was employed to interpret the influence of input variables. The RF surrogate model was then used to estimate the fatigue life of the welded toe in double-sided RD welded joints, and the effects of initial crack geometry on fatigue life were investigated. The results indicate that the initial surface crack at the weld toe is a mode I-dominated mixed-mode crack and exhibits crack flattening during propagation. The RF surrogate model demonstrates high predictive accuracy for SIF, achieving high <em>R</em><sup>2</sup> values and low prediction errors across both training and validation datasets. SHAP analysis identifies applied stress as the primary influencer of SIF, with crack depth and half-length as secondary factors. Increases in initial crack depth and half-length significantly reduce fatigue crack propagation life. This study confirms the robustness of the RF model as a computationally efficient alternative to finite element methods (FEM), providing valuable insights for fatigue assessment and maintenance planning of OSDs.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"187 ","pages":"Article 110582"},"PeriodicalIF":5.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-14DOI: 10.1016/j.engfailanal.2026.110580
Yanwei Huang , Nan Yao , Yicheng Ye
The application of expansive mortar (EM) represents a novel and promising approach for rock mass reinforcement, offering significant improvements in the stability and safety of underground space engineering. However, further integrated theoretical, experimental, and numerical investigations are required to optimize its performance and facilitate broader engineering implementation. To address the inadequate anchorage performance of ordinary mortar (OM) grouted threaded rebar anchors resulting from shrinkage during hardening, this study proposes an expansive mortar grouted threaded rebar anchor (EMGTRA) system, in which controlled volumetric expansion actively enhances interfacial bonding and frictional resistance, thereby improving anchorage capacity. Field pull-out tests combined with FLAC3D numerical simulations were conducted to systematically investigate the pull-out damage characteristics and failure mechanisms of threaded rebar anchors (TRAs) grouted by mortar with different expansive agent contents. The results shows that: (1) the ultimate pull-out resistance of EMGTRAs with a 10% expansive agent content reached 116.7 kN, representing a 59.8% increase compared with OM-grouted anchors; (2) confinement of the rebar ribs by EM strengthened local stress concentrations, leading to improved tensile and bending effects and more effective mobilization of the rebar’s tensile capacity; (3) the expansive stress generated by EM strengthened the mechanical interlocking effect at the anchorage interface, improved slip resistance, and enlarged the mortar damage zone due to rebars rib induced scraping action. These findings reveal the reinforcement mechanisms of EMGTRAs under expansive stress and provide theoretical support and practical guidance for optimizing anchorage design in rock mass engineering.
{"title":"Pull-out damage characteristics and failure mechanisms of anchors grouted with expansive mortar","authors":"Yanwei Huang , Nan Yao , Yicheng Ye","doi":"10.1016/j.engfailanal.2026.110580","DOIUrl":"10.1016/j.engfailanal.2026.110580","url":null,"abstract":"<div><div>The application of expansive mortar (EM) represents a novel and promising approach for rock mass reinforcement, offering significant improvements in the stability and safety of underground space engineering. However, further integrated theoretical, experimental, and numerical investigations are required to optimize its performance and facilitate broader engineering implementation. To address the inadequate anchorage performance of ordinary mortar (OM) grouted threaded rebar anchors resulting from shrinkage during hardening, this study proposes an expansive mortar grouted threaded rebar anchor (EMGTRA) system, in which controlled volumetric expansion actively enhances interfacial bonding and frictional resistance, thereby improving anchorage capacity. Field pull-out tests combined with FLAC3D numerical simulations were conducted to systematically investigate the pull-out damage characteristics and failure mechanisms of threaded rebar anchors (TRAs) grouted by mortar with different expansive agent contents. The results shows that: (1) the ultimate pull-out resistance of EMGTRAs with a 10% expansive agent content reached 116.7 kN, representing a 59.8% increase compared with OM-grouted anchors; (2) confinement of the rebar ribs by EM strengthened local stress concentrations, leading to improved tensile and bending effects and more effective mobilization of the rebar’s tensile capacity; (3) the expansive stress generated by EM strengthened the mechanical interlocking effect at the anchorage interface, improved slip resistance, and enlarged the mortar damage zone due to rebars rib induced scraping action. These findings reveal the reinforcement mechanisms of EMGTRAs under expansive stress and provide theoretical support and practical guidance for optimizing anchorage design in rock mass engineering.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110580"},"PeriodicalIF":5.7,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145972785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1016/j.engfailanal.2026.110577
Hao Liu , Bin Wang , Dali Li , Binxin Dong , Jian Liu , Peijian Chen , Yanhua Bian , Qiansheng Xu , Yu Fan , Xiuli He
High-temperature friction and wear–induced degradation of structural materials is a major factor limiting the service life of critical components operating under severe thermal conditions. In this study, Ni3x(FeCr)yCo(x+y)/2 high-entropy alloys (HEAs) with x/y ratios of 0.5, 0.75, 1.0, and 1.5 were fabricated using laser directed energy deposition (LDED). The objective was to regulate the transition of high-temperature wear-induced failure mechanisms through compositional tuning and age-hardening treatment. The as-deposited alloys consist of an FCC-structured γ matrix and an HCP-structured Laves phase, whose volume fraction decreases with increasing x/y ratio. Age-hardening actively modulates the microstructure, promoting partial dissolution of the Laves phase and the precipitation of nanoscale L12-type γ′ coherent particles. The microhardness of the aged alloys increases with the x/y ratio and is markedly higher than that of the as-deposited condition. High-temperature (600 °C) tribological tests reveal that the wear rate of the as-deposited alloys first increases and then decreases with the x/y ratio, whereas that of the aged alloys decreases monotonically, reaching a minimum value of 3.53 × 10−5 mm3/(N·m) at x/y = 1.5. Age-hardening strengthens the matrix and facilitates the formation of a dense oxide film enriched in Ni and Al, effectively suppressing fatigue-induced spallation of the oxide film. This study shows that tuning composition and applying age-hardening can actively control high-temperature wear failure modes, offering guidance for designing materials with superior high-temperature wear resistance.
{"title":"Failure mechanism transition from fatigue spallation to oxidative wear in age-hardened Ni3x(FeCr)yCo(x+y)/2 high-entropy alloys produced by laser directed energy deposition at elevated temperature","authors":"Hao Liu , Bin Wang , Dali Li , Binxin Dong , Jian Liu , Peijian Chen , Yanhua Bian , Qiansheng Xu , Yu Fan , Xiuli He","doi":"10.1016/j.engfailanal.2026.110577","DOIUrl":"10.1016/j.engfailanal.2026.110577","url":null,"abstract":"<div><div>High-temperature friction and wear–induced degradation of structural materials is a major factor limiting the service life of critical components operating under severe thermal conditions. In this study, Ni<sub>3x</sub>(FeCr)<sub>y</sub>Co<sub>(x+y)/2</sub> high-entropy alloys (HEAs) with x/y ratios of 0.5, 0.75, 1.0, and 1.5 were fabricated using laser directed energy deposition (LDED). The objective was to regulate the transition of high-temperature wear-induced failure mechanisms through compositional tuning and age-hardening treatment. The as-deposited alloys consist of an FCC-structured γ matrix and an HCP-structured Laves phase, whose volume fraction decreases with increasing x/y ratio. Age-hardening actively modulates the microstructure, promoting partial dissolution of the Laves phase and the precipitation of nanoscale L1<sub>2</sub>-type γ′ coherent particles. The microhardness of the aged alloys increases with the x/y ratio and is markedly higher than that of the as-deposited condition. High-temperature (600 °C) tribological tests reveal that the wear rate of the as-deposited alloys first increases and then decreases with the x/y ratio, whereas that of the aged alloys decreases monotonically, reaching a minimum value of 3.53 × 10<sup>−5</sup> mm<sup>3</sup>/(N·m) at x/y = 1.5. Age-hardening strengthens the matrix and facilitates the formation of a dense oxide film enriched in Ni and Al, effectively suppressing fatigue-induced spallation of the oxide film. This study shows that tuning composition and applying age-hardening can actively control high-temperature wear failure modes, offering guidance for designing materials with superior high-temperature wear resistance.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110577"},"PeriodicalIF":5.7,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-11DOI: 10.1016/j.engfailanal.2026.110573
Yu Shi , Peng Liao , Youwei Xu , Wuyao Xiong , Ming Zhu
This study enhances the cavitation erosion resistance in ZL101A aluminum alloy via a Stellite 6 coating fabricated via ultra-high-speed laser cladding (UHSLC). The resulting approximately 400 μm thick coating exhibited a fine-grained microstructure and sound metallurgical bonding. A significant improvement in mechanical and tribological properties was achieved: the microhardness increased dramatically to 683.2 HV (9.3 times that of the substrate), and the friction coefficient was stabilized at 0.35. The coating’s erosion resistance was markedly improved: under solid particle impingement, it showed a mass loss of 21.66 mg and a volume loss of 3.35 mm3, corresponding to reductions of 24 % and 58 %, respectively, compared to the substrate (28.50 mg, 8.02 mm3). After 5 h of cavitation erosion testing in a 3.5 wt% NaCl solution, the coating exhibited a volume loss of 13.88 mm3 and a mass loss of 118 mg, which are 80 % and 38 % lower, respectively, than those of the uncoated ZL101A substrate (70 mm3, 189 mg). This superior performance is attributed to the synergistic effect of the ductile γ-Co solid solution matrix and the interconnected network of Cr7C3/(Cr,Co)2 3C6 hard carbides, which collectively mitigate the impact of cavitation-induced shock waves and micro-jets.
{"title":"Substantial improvement in cavitation erosion resistance of ZL101A aluminum alloy via Ultra-High-Speed laser Cladded Stellite 6 coating","authors":"Yu Shi , Peng Liao , Youwei Xu , Wuyao Xiong , Ming Zhu","doi":"10.1016/j.engfailanal.2026.110573","DOIUrl":"10.1016/j.engfailanal.2026.110573","url":null,"abstract":"<div><div>This study enhances the cavitation erosion resistance in ZL101A aluminum alloy via a Stellite 6 coating fabricated via ultra-high-speed laser cladding (UHSLC). The resulting approximately 400 μm thick coating exhibited a fine-grained microstructure and sound metallurgical bonding. A significant improvement in mechanical and tribological properties was achieved: the microhardness increased dramatically to 683.2 HV (9.3 times that of the substrate), and the friction coefficient was stabilized at 0.35. The coating’s erosion resistance was markedly improved: under solid particle impingement, it showed a mass loss of 21.66 mg and a volume loss of 3.35 mm3, corresponding to reductions of 24 % and 58 %, respectively, compared to the substrate (28.50 mg, 8.02 mm3). After 5 h of cavitation erosion testing in a 3.5 wt% NaCl solution, the coating exhibited a volume loss of 13.88 mm<sup>3</sup> and a mass loss of 118 mg, which are 80 % and 38 % lower, respectively, than those of the uncoated ZL101A substrate (70 mm<sup>3</sup>, 189 mg). This superior performance is attributed to the synergistic effect of the ductile γ-Co solid solution matrix and the interconnected network of Cr<sub>7</sub>C<sub>3</sub>/(Cr,Co)<sub>2 3</sub>C<sub>6</sub> hard carbides, which collectively mitigate the impact of cavitation-induced shock waves and micro-jets.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110573"},"PeriodicalIF":5.7,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study investigates the bio electrochemical impact of varying Headspace Volumes (HSV) as a key environmental control factor in the Microbiologically Influenced Corrosion (MIC) induced failure of API 5 L X65 pipeline steel. The degradation was driven by Enterobacter cloacae SCO6, a facultative anaerobe isolated from crude oil conveying infrastructure. The results quantitatively demonstrate that HSV significantly modulates the redox environment and metabolic state, thereby drastically accelerating the material failure rate. A clear, detrimental dependence on HSV was observed: the overall corrosion rate increased sharply from 9.84 to 25.20 mils/year as the HSV was expanded from 30 mL to 180 mL, a nearly fivefold acceleration compared to the abiotic control rate of 5.91mils/year. This escalating failure was confirmed by a consistent monotonic trend (ρ = 1, p = 0.03) between increasing bacterial counts and the rate of steel depolarization. Microstructural failure analysis via scanning electron microscopy and surface profilometry confirmed that higher HSV conditions promote highly aggressive localized attack, with maximum pit depths soaring from 6.61 µm (30 mL) to a severe16.85 µm (180 mL). Mechanistically, this failure acceleration is attributed to the HSV controlling dissolved H2S concentrations which enhances microbial viability and intensifies the extracellular electron transfer mechanism at the biofilm-electrode interface. This research provides crucial quantitative and mechanistic insight into how common operational gradients lead to unforeseen pipeline failure. This understanding is essential for optimizing maintenance protocols, implementing robust risk assessment and ultimately improving the longevity and safety of oil and gas infrastructure.
{"title":"Critical role of headspace volume in Microbiologically induced failure of API 5 L X65 pipeline steel: A bio electrochemical mechanism study using facultative anaerobe Enterobacter cloacae SCO6","authors":"C.A. Shefeena , Jesmi Yousuf , C.B. Sudheer , A.A Mohamed Hatha , A. Mathiazhagan , P.K Satheesh Babu , K.P Anand","doi":"10.1016/j.engfailanal.2026.110572","DOIUrl":"10.1016/j.engfailanal.2026.110572","url":null,"abstract":"<div><div>This study investigates the bio electrochemical impact of varying Headspace Volumes (HSV) as a key environmental control factor in the Microbiologically Influenced Corrosion (MIC) induced failure of API 5 L X65 pipeline steel. The degradation was driven by <em>Enterobacter cloacae</em> SCO6, a facultative anaerobe isolated from crude oil conveying infrastructure. The results quantitatively demonstrate that HSV significantly modulates the redox environment and metabolic state, thereby drastically accelerating the material failure rate. A clear, detrimental dependence on HSV was observed: the overall corrosion rate increased sharply from 9.84 to 25.20 mils/year as the HSV was expanded from 30 mL to 180 mL, a nearly fivefold acceleration compared to the abiotic control rate of 5.91mils/year. This escalating failure was confirmed by a consistent monotonic trend (ρ = 1, p = 0.03) between increasing bacterial counts and the rate of steel depolarization. Microstructural failure analysis via scanning electron microscopy and surface profilometry confirmed that higher HSV conditions promote highly aggressive localized attack, with maximum pit depths soaring from 6.61 µm (30 mL) to a severe16.85 µm (180 mL). Mechanistically, this failure acceleration is attributed to the HSV controlling dissolved H<sub>2</sub>S concentrations which enhances microbial viability and intensifies the extracellular electron transfer mechanism at the biofilm-electrode interface. This research provides crucial quantitative and mechanistic insight into how common operational gradients lead to unforeseen pipeline failure. This understanding is essential for optimizing maintenance protocols, implementing robust risk assessment and ultimately improving the longevity and safety of oil and gas infrastructure.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110572"},"PeriodicalIF":5.7,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-11DOI: 10.1016/j.engfailanal.2026.110574
Alaa E. Abdelmoniem, M. Megahed, Mohamad A. Hassan, Ahmed Ibrahim
This study attempts to restore the quasi-static indentation (QSI) performance of damaged woven and chopped glass-fiber/epoxy laminates by applying different repair methods which are low cost and easy to apply. Four different repair techniques were applied to the delaminated glass-fiber/epoxy Laminates. Compared to the pristine specimen, the traditional patch repair was capable of restoring 39.5 % and 48.98 % in terms of maximum load capacity for both woven and chopped laminates. Injection repair after rebounding the surface to its original geometry, by applying heat 90 °C and pressure 20 kg, has 71.13 % and 56.87 % efficiency of maximum load recovery for both W and C specimens. Two different stitching repair patterns were developed to the damaged zone in order to study to what extent this method of stitching would restore the original load capacity. Every pattern reveals a significant percentage of restoring the original indentation performance. The first stitching pattern results 87.02 % and 82.32 % for woven/epoxy and chopped/epoxy composites, respectively. The other pattern shows distinctive powerful ability in restoring maximum load capacity as 101.7 % and 98.33 % for woven/epoxy and chopped/epoxy composites, respectively. Also, the efficiency of the repair techniques in terms of the absorbed energy was investigated during this work. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy analysis are performed to indicate and quantify the subsurface delamination and to confirm the restoration at the fiber/matrix interface.
{"title":"The influence of localized repair techniques on the indentation performance of delaminated glass-fiber/epoxy laminates","authors":"Alaa E. Abdelmoniem, M. Megahed, Mohamad A. Hassan, Ahmed Ibrahim","doi":"10.1016/j.engfailanal.2026.110574","DOIUrl":"10.1016/j.engfailanal.2026.110574","url":null,"abstract":"<div><div>This study attempts to restore the quasi-static indentation (QSI) performance of damaged woven and chopped glass-fiber/epoxy laminates by applying different repair methods which are low cost and easy to apply. Four different repair techniques were applied to the delaminated glass-fiber/epoxy Laminates. Compared to the pristine specimen, the traditional patch repair was capable of restoring 39.5 % and 48.98 % in terms of maximum load capacity for both woven and chopped laminates. Injection repair after rebounding the surface to its original geometry, by applying heat 90 °C and pressure 20 kg, has 71.13 % and 56.87 % efficiency of maximum load recovery for both W and C specimens. Two different stitching repair patterns were developed to the damaged zone in order to study to what extent this method of stitching would restore the original load capacity. Every pattern reveals a significant percentage of restoring the original indentation performance. The first stitching pattern results 87.02 % and 82.32 % for woven/epoxy and chopped/epoxy composites, respectively. The other pattern shows distinctive powerful ability in restoring maximum load capacity as 101.7 % and 98.33 % for woven/epoxy and chopped/epoxy composites, respectively. Also, the efficiency of the repair techniques in terms of the absorbed energy was investigated during this work. Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy analysis are performed to indicate and quantify the subsurface delamination and to confirm the restoration at the fiber/matrix interface.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110574"},"PeriodicalIF":5.7,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-11DOI: 10.1016/j.engfailanal.2026.110541
Si Zhang, Nuoyi Wu, Chuanbo An, Zhiying Sun, Xu Li, Fuying Zhao, Xiaoxue Wang, Yun Chen
Understanding progressive failure in woven carbon fiber composites is essential for reliable load-bearing applications. This study investigates the tensile failure mechanisms of plain-woven carbon fiber laminates with a polyimine-modified epoxy (EP-PI) matrix using combined experiments and multiscale finite element (FE) modeling. A hierarchical RVE-based framework is established to link the fiber/matrix, yarn, and laminate scales, where micromechanical stress-based criteria and a Hashin-type progressive damage model are employed to describe matrix cracking, damage growth, and final fiber bundle rupture. Under a perfectly bonded microscale interface assumption (shared nodes, no explicit cohesive/contact interface), the influence of EP-PI is incorporated effectively through bulk matrix properties and damage parameters that govern matrix-dominated damage initiation and evolution. The predicted stress–strain response agrees well with the tensile experiments, with a 1.1 % deviation in peak load, and the model reproduces the dominant damage sequence observed in tests. The results indicate that matrix cracking initiates damage, followed by stress redistribution and subsequent fiber bundle failure. Overall, the proposed framework provides a reproducible multiscale baseline for failure analysis of woven CFRP laminates and supports structural assessment of EP–PI based composite components under tensile loading.
{"title":"Multiscale finite element prediction and experimental validation of progressive tensile failure in plain-woven carbon fiber composites with polyimine-modified epoxy matrix","authors":"Si Zhang, Nuoyi Wu, Chuanbo An, Zhiying Sun, Xu Li, Fuying Zhao, Xiaoxue Wang, Yun Chen","doi":"10.1016/j.engfailanal.2026.110541","DOIUrl":"10.1016/j.engfailanal.2026.110541","url":null,"abstract":"<div><div>Understanding progressive failure in woven carbon fiber composites is essential for reliable load-bearing applications. This study investigates the tensile failure mechanisms of plain-woven carbon fiber laminates with a polyimine-modified epoxy (EP-PI) matrix using combined experiments and multiscale finite element (FE) modeling. A hierarchical RVE-based framework is established to link the fiber/matrix, yarn, and laminate scales, where micromechanical stress-based criteria and a Hashin-type progressive damage model are employed to describe matrix cracking, damage growth, and final fiber bundle rupture. Under a perfectly bonded microscale interface assumption (shared nodes, no explicit cohesive/contact interface), the influence of EP-PI is incorporated effectively through bulk matrix properties and damage parameters that govern matrix-dominated damage initiation and evolution. The predicted stress–strain response agrees well with the tensile experiments, with a 1.1 % deviation in peak load, and the model reproduces the dominant damage sequence observed in tests. The results indicate that matrix cracking initiates damage, followed by stress redistribution and subsequent fiber bundle failure. Overall, the proposed framework provides a reproducible multiscale baseline for failure analysis of woven CFRP laminates and supports structural assessment of EP–PI based composite components under tensile loading.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110541"},"PeriodicalIF":5.7,"publicationDate":"2026-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-10DOI: 10.1016/j.engfailanal.2026.110561
Yuqiang Pan , Xiaokai Niu , Wei Li , Zixian Jin , Kun Huang , Jie Su , Chengping Zhang
Crack propagation critically threatens the structural integrity of urban underground tunnel linings. This study employs an integrated experimental and numerical methodology, combining scaled model tests with peridynamic (PD) simulations, to investigate cracking mechanisms and quantify the effects of pre-existing cracks in a case study of Beijing Subway Line 1. The complete cracking process, internal force redistribution, and ultimate failure modes are analyzed. Results identify a sequential failure pattern: cracks initially initiate at the invert, subsequently appear at the crown, and then interconnect at the springlines, ultimately leading to structural collapse. Pre-existing cracks are shown to significantly degrade structural stiffness and bearing capacity, with severity increasing with crack depth. Specifically, a crack depth of half the lining thickness reduces the ultimate bearing capacity by 24 %–26 % at the crown and up to 30 % at the invert. This work validates the PD method for tunnel fracture analysis and assessing the safety of tunnel linings.
{"title":"Peridynamic simulation on crack propagation and mechanical properties of tunnel linings with cracks","authors":"Yuqiang Pan , Xiaokai Niu , Wei Li , Zixian Jin , Kun Huang , Jie Su , Chengping Zhang","doi":"10.1016/j.engfailanal.2026.110561","DOIUrl":"10.1016/j.engfailanal.2026.110561","url":null,"abstract":"<div><div>Crack propagation critically threatens the structural integrity of urban underground tunnel linings. This study employs an integrated experimental and numerical methodology, combining scaled model tests with peridynamic (PD) simulations, to investigate cracking mechanisms and quantify the effects of pre-existing cracks in a case study of Beijing Subway Line 1. The complete cracking process, internal force redistribution, and ultimate failure modes are analyzed. Results identify a sequential failure pattern: cracks initially initiate at the invert, subsequently appear at the crown, and then interconnect at the springlines, ultimately leading to structural collapse. Pre-existing cracks are shown to significantly degrade structural stiffness and bearing capacity, with severity increasing with crack depth. Specifically, a crack depth of half the lining thickness reduces the ultimate bearing capacity by 24 %–26 % at the crown and up to 30 % at the invert. This work validates the PD method for tunnel fracture analysis and assessing the safety of tunnel linings.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"186 ","pages":"Article 110561"},"PeriodicalIF":5.7,"publicationDate":"2026-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145973285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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