Engineering Failure Analysis最新文献_第9页

Fragmentation behavior and velocity formula for secondary fragments from RC slabs during contact explosions 接触爆炸时钢筋混凝土板二次碎片的碎裂行为和速度公式

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-06 DOI: 10.1016/j.engfailanal.2024.109047

Shixu Guo , Xiang He , Fei Liu , Jianchao Yang , Shanchuan Sun

{"title":"Fragmentation behavior and velocity formula for secondary fragments from RC slabs during contact explosions","authors":"Shixu Guo , Xiang He , Fei Liu , Jianchao Yang , Shanchuan Sun","doi":"10.1016/j.engfailanal.2024.109047","DOIUrl":"10.1016/j.engfailanal.2024.109047","url":null,"abstract":"<div><div>The failure process of reinforced concrete (RC) slabs under contact explosion is dominated by localized damages, accompanied by numerous flying fragments. These concrete fragments pose a significant threat to personnel and equipment, as well as causing dynamic deformation and failure of the retrofitting materials used to restrain the fragments. The behavior of concrete fragmentation during explosions has been seldom studied experimentally, and few fragment velocity formulas exist that incorporate multiple factors. In this paper, the fragmentation process is recorded using two high-speed cameras, revealing that concrete fragmentation during explosions exhibits notable zoning characteristics, with the maximum velocity observed at the center of the fragment cloud’s front. To predict this maximum velocity, a model is derived from dimensional analysis. Utilizing this model, velocity prediction formulas are proposed and validated by 29 contact explosion tests. The formulas consider the explosive-rebar position, slab thickness, explosive mass and explosive shape, and are further improved by considering the concrete cover. The results indicate that, when the slab is not breached, the deceleration of rebar on fragments is weak. However, once the slab is breached, this deceleration becomes increasingly significant as the defined scaled thickness (<em>T</em><sub>S</sub>) decreases. In the limiting case, the fragment velocity when the charge is located above the rebar is 0.636 times that of when the charge avoids the rebar. Fragments when the charge avoids the rebar, should be regarded as the most unfavorable case in secondary fragment hazards assessment and structural design.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109047"},"PeriodicalIF":4.4,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142661309","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}

引用次数: 0

Comparison of hydrogen effects on additively manufactured and conventional austenitic steels 比较氢对快速成型钢和传统奥氏体钢的影响

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-05 DOI: 10.1016/j.engfailanal.2024.109042

Jonathan Nietzke , Florian Konert , Konstantin Poka , Benjamin Merz , Oded Sobol , Thomas Böllinghaus

{"title":"Comparison of hydrogen effects on additively manufactured and conventional austenitic steels","authors":"Jonathan Nietzke , Florian Konert , Konstantin Poka , Benjamin Merz , Oded Sobol , Thomas Böllinghaus","doi":"10.1016/j.engfailanal.2024.109042","DOIUrl":"10.1016/j.engfailanal.2024.109042","url":null,"abstract":"<div><div>Hydrogen and its derivatives are promising energy carriers for future renewable energy supplies. Austenitic stainless steels, such as AISI 316L, are commonly used in hydrogen transportation systems. While often thought to be resistant to hydrogen embrittlement, studies have shown that 316L is susceptible under certain conditions. As demand for hydrogen applications grows, additive manufacturing (AM) technologies offer design flexibility and customisation benefits. However, data on AM parts behaviour in hydrogen environments is lacking. This study investigates the influence of hydrogen on mechanical properties using slow strain rate testing (SSRT) on conventional AISI 304L, 316L and AM 316L specimens. The results indicate a greater effect of hydrogen on 304L compared to 316L, with AM 316L showing increased susceptibility. However, the ductility of AM 316L remains comparable to conventional 316L due to its initial ductility. The study provides insights into the performance of conventional and AM austenitic stainless steels in gaseous hydrogen environments.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109042"},"PeriodicalIF":4.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

25 years field test history and fatigue damage analysis for a scrapped ladle crane 一台报废钢包起重机 25 年的现场测试历史和疲劳损伤分析

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-05 DOI: 10.1016/j.engfailanal.2024.109043

Guoqian Wei , Huan Xu , You Zhao , Zhang Dang , Zhiwen Lu

{"title":"25 years field test history and fatigue damage analysis for a scrapped ladle crane","authors":"Guoqian Wei , Huan Xu , You Zhao , Zhang Dang , Zhiwen Lu","doi":"10.1016/j.engfailanal.2024.109043","DOIUrl":"10.1016/j.engfailanal.2024.109043","url":null,"abstract":"<div><div>Fatigue performances of ladle cranes will gradually decrease with the increase of service years. The service history and the fatigue damage of a scrapped ladle crane were investigated and analyzed in this paper. The test history of the ladle crane was collected and concluded, and the statistical parameters of lifting capacity and the crack condition during service were determined. The last comprehensive field test before scrapping the ladle crane was introduced in detail and the damage evolution was analyzed. The geometry measurement showed that the main girders’ stiffness had changed obviously. The stress test of the crack-prone positions of the metal structure revealed their remaining bearing capacity and the damage evolution characteristics. Further analysis proved that the static stiffness of the main girder has a closer relationship with damage deterioration. Some material property inspections were carried out for samples cut from the scrapped crane’s main girder, which were of the load-carrying part and the non-load-carrying part respectively. Results showed that the elastic modulus and hardness of the materials decreased evidently after service, while other mechanical properties did not change significantly. This study will provide useful references for further understanding of the fatigue characteristics and evolution behaviors of ladle cranes.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109043"},"PeriodicalIF":4.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660944","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}

引用次数: 0

Rail rolling contact fatigue on a Chinese heavy haul line: Observations, monitoring and simulations 中国重载运输线上的铁轨滚动接触疲劳：观察、监测和模拟

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-05 DOI: 10.1016/j.engfailanal.2024.109040

X. Zhao , Y.H. Xing , X. Zhang , F. Peng , H.D. Xue , Y.L. Han

{"title":"Rail rolling contact fatigue on a Chinese heavy haul line: Observations, monitoring and simulations","authors":"X. Zhao , Y.H. Xing , X. Zhang , F. Peng , H.D. Xue , Y.L. Han","doi":"10.1016/j.engfailanal.2024.109040","DOIUrl":"10.1016/j.engfailanal.2024.109040","url":null,"abstract":"<div><div>Severe rail rolling contact fatigue (RCF) occurring on curves of a heavy haul line in China was studied by field observations, monitoring tests, failure analyses and numerical simulations. Visual appearance, worn profiles, surface hardness, crack dimensions and so on were measured in field for rails and typical running wheels, meanwhile other related information was also collected. Significant influences of the radius of curvature and loaded/empty trains were figured out. RCF cracks on R600 m curves was found to get initiated in days, propagated downward very quickly in the first 2 months, and then stabilized at a depth of about 2.5 mm until rail replacement owing to further propagation into un-flowed bulk material. Though the failure analyses, crack depths measured by an eddy current detector were verified. Considering measured/collected data, a numerical approach combining a train dynamic model and the damage function model (Tγ) has been developed to predict the rail RCF occurrence, in which the influence of trapped liquids was better modelled by introducing a critical angle of the resultant creep force. Typical simulations showed that numerical predictions could well explain the observed phenomena, providing a useful tool for further studies.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109040"},"PeriodicalIF":4.4,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660945","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}

引用次数: 0

Buckling and failure mechanisms of asymmetric composite sandwich panels subjected to shear loadings 非对称复合夹芯板在剪切荷载作用下的屈曲和破坏机理

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-04 DOI: 10.1016/j.engfailanal.2024.109039

Jian Deng , Jiatao Zhao , Ang Peng , Dake Wu , Zhibo Wu , Guangming Zhou

{"title":"Buckling and failure mechanisms of asymmetric composite sandwich panels subjected to shear loadings","authors":"Jian Deng , Jiatao Zhao , Ang Peng , Dake Wu , Zhibo Wu , Guangming Zhou","doi":"10.1016/j.engfailanal.2024.109039","DOIUrl":"10.1016/j.engfailanal.2024.109039","url":null,"abstract":"<div><div>Asymmetric sandwich technology serves as an effective option for introducing loads into sandwich structures in lieu of conventional inserts and joints in lightweight design of thin-walled aeronautical applications. In this study, buckling and failure behaviors are investigated on asymmetric sandwich panels with tapered regions subjected to shearing, where the panels are composed of CFRP laminates as skins and PMI foam as the core. Experimental data and observations are analyzed regarding critical loads, strain distributions, macro- and micro-scaled failure mechanisms. Detailed damage evolution is captured with the developed material and structural models. The influence of the core thickness on stability, load-bearing capacity and failure mechanisms is further investigated. Results show that the shear failure is mainly induced by buckling with an extensive matrix splitting fracture along the diagonal direction for sandwich panels with thin cores. Nonlinearity is observed in strain and deflection responses. Fiber pull-out is formed due to losing support of neighboring matrix. The fracture morphology of fiber breakage roughly appears oblique, indicating that the failure is mainly caused by the combination of tension and shearing. For sandwich panels with a thicker core, i.e. 10 mm and 12 mm, the failure mode switches to pure shear failure. Due to the intensification of tapered edges, local bugling occurs simultaneously with ultimate failure. The ultimate load presents a mounting-up and declining trend with the increase of core thickness, other than a monotonic trend. Conclusively, optimal design parameters exist, such as 10 mm core thickness in the studied case, regarding the load-bearing capacity.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109039"},"PeriodicalIF":4.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593151","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}

引用次数: 0

Structural response of precast reinforced concrete structure with emulative moment connections under internal column loss scenarios 预制钢筋混凝土结构的结构响应与内部支柱损失情况下的模拟弯矩连接

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-04 DOI: 10.1016/j.engfailanal.2024.108995

Chenchen Wang, Kian Hau Kong, Leong Hien Poh

{"title":"Structural response of precast reinforced concrete structure with emulative moment connections under internal column loss scenarios","authors":"Chenchen Wang, Kian Hau Kong, Leong Hien Poh","doi":"10.1016/j.engfailanal.2024.108995","DOIUrl":"10.1016/j.engfailanal.2024.108995","url":null,"abstract":"<div><div>Depending on the design, the connections of precast concrete (PC) structures can be susceptible to severe damage under large deformation. Consequently, PC structures may behave differently from cast-in-situ reinforced concrete (RC) structures under column loss scenarios. This study focuses on a class of PC structures that utilize splice sleeves (SSs) to assemble the precast components with integrated beam-column connections (IBCCs). This PC design can alleviate rebar congestion issues and minimize the need for post-cast concrete in the connection regions during assembly. The IBCCs are typically designed to mimic the behavior of corresponding RC connections under service loading conditions. However, the extent of structural emulation under column loss scenarios is not immediately clear. In this paper, the collapse behavior of PC structures with IBCCs under an internal column removal scenario is thoroughly assessed using experimental investigations and numerical analyses. Three PC subassemblages and one RC subassemblage are tested experimentally to provide experimental data for the calibration and validation of finite element (FE) models. The collapse behavior of full-span PC and RC subassemblages are next compared numerically under the internal column loss scenario, with an accompanying investigation on the influence of horizontal SSs. It is found that the PC subassemblages exhibit emulative collapse behavior as the RC subassemblage under internal column loss scenarios, provided that the horizontal SSs are located beyond the beam plastic region under the internal column loss scenario. To achieve the latter, a minimum distance of 0.15 L (L is clear beam span before column removal) is recommended for the positioning of horizontal SSs under the internal column loss scenario. Finally, it is shown that the fracture load and corresponding displacement can be enhanced with the incorporation of high ductility rebars.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 108995"},"PeriodicalIF":4.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660884","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}

引用次数: 0

Model test study on instability mechanism during shield under-crossing existing pipeline 盾构下穿现有管道时的失稳机理模型试验研究

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-04 DOI: 10.1016/j.engfailanal.2024.109041

Xiaopu Cui , Pengfei Li , Zeshuai Ma , Qing Xu , Fei Jia , Zhaoguo Ge , Shaohua Li

{"title":"Model test study on instability mechanism during shield under-crossing existing pipeline","authors":"Xiaopu Cui , Pengfei Li , Zeshuai Ma , Qing Xu , Fei Jia , Zhaoguo Ge , Shaohua Li","doi":"10.1016/j.engfailanal.2024.109041","DOIUrl":"10.1016/j.engfailanal.2024.109041","url":null,"abstract":"<div><div>This paper aims at investigating the instability mechanism that occurs during the under-crossing of an existing pipeline using model tests and numerical simulations. The strain in the pipeline, earth pressure, surface settlement, and mechanisms of stratum instability during the process of instability have been obtained. The research findings reveal three distinct growth stages in the longitudinal deformation of the existing pipeline, with the strain growth rate during the rapid growth phase being 2–3 times higher than that observed during the slow growth phase. The pipeline displays a deformation pattern with tensile stress in the upper section and compressive stress in the lower section, due to the uneven force distribution along its length. In the absence of pipelines, the distribution of surface collapse exhibits a distinct “V” shaped. As the clear distance between the existing pipeline and the tunnel (CDPT) increases, there is a transition from a “partial W” to a “positive W” type distribution. The presence of the pipeline exerts the most significant inhibiting effect on the soil directly above it. In cases where there is no pipeline or the CDPT is small, soil leakage primarily occurs in front of the excavation. As the CDPT increases, soil leakage occurs around the pipeline and the instability range of the stratum significantly expands. The stable strata above the pipeline gradually widen, and the area with a significant influence range shifts from the right side to the left side of the existing pipeline.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109041"},"PeriodicalIF":4.4,"publicationDate":"2024-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660941","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}

引用次数: 0

Research on TBM parameter optimization based on failure probability 基于失效概率的 TBM 参数优化研究

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-02 DOI: 10.1016/j.engfailanal.2024.109036

Qian Zhang , Yaoqi Nie , Weigang Zhao , Lijie Du

{"title":"Research on TBM parameter optimization based on failure probability","authors":"Qian Zhang , Yaoqi Nie , Weigang Zhao , Lijie Du","doi":"10.1016/j.engfailanal.2024.109036","DOIUrl":"10.1016/j.engfailanal.2024.109036","url":null,"abstract":"<div><div>This study addresses the over-reliance on operator experience in Tunnel Boring Machine (TBM) operations by proposing a failure probability-based decision-making method to enhance the scientific accuracy and reliability of construction decisions. In large deformation soft rock zones, TBMs are significantly affected by surrounding rock stress and deformation, which can lead to reduced tunneling speed or even shield jamming, severely impacting construction progress and safety. To reduce subjective biases in operator decision-making, this study combines the stress release coefficient with a failure probability model to establish a limit equilibrium equation. Using Monte Carlo simulations, failure probabilities under varying geological conditions are evaluated, and the optimal tunneling parameters are selected by analyzing the cumulative effect over time. Additionally, the study incorporates a Bayesian updating method, dynamically adjusting model parameters based on periodic monitoring data, further reducing uncertainty and improving the accuracy of the decision support system. The results show that while higher tunneling speeds increase the instantaneous failure probability, considering the cumulative effect over time, the overall failure index decreases with increased speed. Conversely, lower speeds result in a lower instantaneous failure probability but prolonged exposure to high-risk conditions increases the overall failure index. With this decision-making method, operators can quantitatively and in real-time adjust tunneling parameters under complex geological conditions, minimizing failure risks and improving construction efficiency.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109036"},"PeriodicalIF":4.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593077","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}

引用次数: 0

Corrosion fatigue analysis of suspenders on continuous suspension bridge under combined action of wind and traffic 风和交通联合作用下连续悬索桥吊索的腐蚀疲劳分析

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-02 DOI: 10.1016/j.engfailanal.2024.109037

Zhijie Yuan , Hao Wang , Rou Li , Lingxiao Wang , Jianxiao Mao , Hai Zong

{"title":"Corrosion fatigue analysis of suspenders on continuous suspension bridge under combined action of wind and traffic","authors":"Zhijie Yuan , Hao Wang , Rou Li , Lingxiao Wang , Jianxiao Mao , Hai Zong","doi":"10.1016/j.engfailanal.2024.109037","DOIUrl":"10.1016/j.engfailanal.2024.109037","url":null,"abstract":"<div><div>Suspenders and displacement-controlled device (DCD) are crucial force transmission components connecting the girder and the main cable in the continuous suspension bridge. These two structures will be subjected to environmental corrosion and fatigue loading simultaneously after the protection system fails. To investigate the safety of structure during the service, a comprehensive framework for corrosion fatigue analysis of continuous suspension bridge under the combined effects of wind and traffic flow was proposed. Taking a three-span continuous suspension bridge with DCD as engineering background, the wind-traffic combined load model was established and the fatigue life of the corroded suspenders was examined. Based on the Multilayer Perceptron algorithm, the impact of load form, environmental grade and DCD type on the corrosion fatigue performance of suspenders was analyzed. The results indicate that the fatigue life of suspender is significantly reduced due to uniform and pitting corrosion of the internal steel wires. The early failure mechanism of suspender is extremely sensitive to corrosion factors. Traffic load is the primary cause of fatigue damage to suspenders. Setting up DCD is beneficial for improving the corrosion fatigue life of the suspenders, and the selection of DCD type mainly depends on the topographical factors of the bridge site.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109037"},"PeriodicalIF":4.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593149","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}

引用次数: 0

The impact of water contamination on the performance failure of lithium grease 水污染对锂基润滑脂性能故障的影响

IF 4.4 2区工程技术

Engineering Failure Analysis Pub Date : 2024-11-02 DOI: 10.1016/j.engfailanal.2024.109035

Qilong Zhao , Enhui Zhang , Cheng Jiang , Kuiliang Gong , Wenjing Lou , Ruliang Zhang , Xiaobo Wang

{"title":"The impact of water contamination on the performance failure of lithium grease","authors":"Qilong Zhao , Enhui Zhang , Cheng Jiang , Kuiliang Gong , Wenjing Lou , Ruliang Zhang , Xiaobo Wang","doi":"10.1016/j.engfailanal.2024.109035","DOIUrl":"10.1016/j.engfailanal.2024.109035","url":null,"abstract":"<div><div>The performance of grease is significantly influenced by water contamination in humid environments, such as those found in mines and offshore wind farms. In this study, the impact of water contamination on the physicochemical properties, rheological properties, film thickness and tribological properties of lithium greases was evaluated using a series of instruments and techniques, including rheometer, ball-on-disc contact test rig, UMT tribometer and others. Results show that the water content of 2% can enhance both the shear resistance and the extreme pressure capacity of lithium-based grease. The shear viscosity and the structural recoverability increase when water content is below 4%. However, when the water content reaches 8%, the equilibrium of the grease-water composite system is disrupted, resulting in the formation of soap fiber surface breakage notches and a notable reduction in shear viscosity. Furthermore, grease with a water content of 2% to 4% is capable of forming a thicker multi-phase mixed lubrication film, wherein soap fibers, base oil and water coexist. Conversely, the film thickness is observed to diminish rapidly when the water content reaches 6% to 10%. Moreover, the oil–water mixture exhibits inadequate lubricating oil film recovery ability in boundary lubrication. The coefficient of friction of water-contaminated grease increases significantly, reaching 2–3 times that of the initial fully lubricated state at a certain point with severe surface wear. These findings provide technical support for the utilization of lubricants in humid environments and highlight the potential impact of water contamination on lubricant performance.</div></div>","PeriodicalId":11677,"journal":{"name":"Engineering Failure Analysis","volume":"167 ","pages":"Article 109035"},"PeriodicalIF":4.4,"publicationDate":"2024-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593147","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}

引用次数: 0