Pub Date : 2024-11-16DOI: 10.1016/j.ijfatigue.2024.108715
Yong Cai , Ziming Wang , Yihu Tang , Congcong Xu , Yingwei Song , Kaihui Dong , En-Hou Han
The clean fuels of ammonia and methanol are used to replace diesel in shipbuilding industry, but there exists corrosion risk for the engine parts in combustion products. The corrosion fatigue behavior of cylinder liners cast iron in simulated combustion product solutions of ammonia, methanol and diesel fuels were investigated. The corrosion rate and corrosion fatigue sensitivity in the three simulated solutions are ammonia fuel < diesel fuel < methanol fuel. The type B graphite causes more severe matrix corrosion than type A flake graphite, and the ternary phosphorus eutectic has no significant effect on corrosion. For ammonia fuel, fatigue damage is dominated by stress concentration induced by flake graphite and phosphorous eutectic. For methanol and diesel, fatigue damage is mainly dominated by corrosion process induced by flake graphite.
造船业使用氨和甲醇等清洁燃料替代柴油，但燃烧产物对发动机部件存在腐蚀风险。研究了气缸套铸铁在氨气、甲醇和柴油燃料的模拟燃烧产物溶液中的腐蚀疲劳行为。三种模拟溶液的腐蚀速率和腐蚀疲劳敏感性分别为氨燃料、柴油燃料和甲醇燃料。与 A 型鳞片石墨相比，B 型石墨会导致更严重的基体腐蚀，而三元磷共晶对腐蚀没有明显影响。对于氨燃料，疲劳破坏主要是由鳞片石墨和磷共晶引起的应力集中造成的。对于甲醇和柴油，疲劳破坏主要是由鳞片石墨引起的腐蚀过程造成的。
{"title":"Corrosion fatigue behavior of cast iron in simulated combustion product solutions of ammonia and methanol fuels","authors":"Yong Cai , Ziming Wang , Yihu Tang , Congcong Xu , Yingwei Song , Kaihui Dong , En-Hou Han","doi":"10.1016/j.ijfatigue.2024.108715","DOIUrl":"10.1016/j.ijfatigue.2024.108715","url":null,"abstract":"<div><div>The clean fuels of ammonia and methanol are used to replace diesel in shipbuilding industry, but there exists corrosion risk for the engine parts in combustion products. The corrosion fatigue behavior of cylinder liners cast iron in simulated combustion product solutions of ammonia, methanol and diesel fuels were investigated. The corrosion rate and corrosion fatigue sensitivity in the three simulated solutions are ammonia fuel < diesel fuel < methanol fuel. The type B graphite causes more severe matrix corrosion than type A flake graphite, and the ternary phosphorus eutectic has no significant effect on corrosion. For ammonia fuel, fatigue damage is dominated by stress concentration induced by flake graphite and phosphorous eutectic. For methanol and diesel, fatigue damage is mainly dominated by corrosion process induced by flake graphite.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108715"},"PeriodicalIF":5.7,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663098","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 new nonlinear fatigue cumulative damage model is proposed to address the challenge of insufficient accuracy in calculations stemming from nonlinear cumulative damage models that fail to account for strength degradation effects and interactions among multi-level loads. This model, an enhancement of the Aeran fatigue damage model, incorporates stress ratios to capture load interactions and includes a logarithmic residual strength degradation model extended to multi-level stress states. Comparative analysis of this model against the Miner model and two other models across various material fatigue datasets shows superior predictive accuracy. Specifically, the new model demonstrates a 74.43% improvement over the Aeran model under six-level loading conditions. Its straightforward mathematical formulation makes it practical for engineering applications in fatigue life prediction.
{"title":"A new nonlinear fatigue cumulative damage model based on load interaction and strength degradation","authors":"Qian Xiao, Xilin Wang, Daoyun Chen, Xinjian Zhou, Xinlong Liu, Wenbin Yang","doi":"10.1016/j.ijfatigue.2024.108709","DOIUrl":"10.1016/j.ijfatigue.2024.108709","url":null,"abstract":"<div><div>A new nonlinear fatigue cumulative damage model is proposed to address the challenge of insufficient accuracy in calculations stemming from nonlinear cumulative damage models that fail to account for strength degradation effects and interactions among multi-level loads. This model, an enhancement of the Aeran fatigue damage model, incorporates stress ratios to capture load interactions and includes a logarithmic residual strength degradation model extended to multi-level stress states. Comparative analysis of this model against the Miner model and two other models across various material fatigue datasets shows superior predictive accuracy. Specifically, the new model demonstrates a 74.43% improvement over the Aeran model under six-level loading conditions. Its straightforward mathematical formulation makes it practical for engineering applications in fatigue life prediction.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108709"},"PeriodicalIF":5.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.ijfatigue.2024.108673
Rui Su , Qianli Liu , Haizhou Li , Dirui Wang , Jinquan Guo , Shengbo Li , Wantong Wang , Aixin Feng , Zhongtao Sun , Hui Chen
Titanium alloy welded structures are often subjected to cyclic loading with composite waveform and variable amplitude during actual service, exacerbating the damage to the joints and leading to low fatigue life. Therefore, a three-stage heat treatment was adopted in this work to enhance the fatigue life of TC4 titanium alloy pulsed laser-arc hybrid welded joints, and its microstructure evolution and fracture mechanism were investigated. The results show that the high-density phase boundary formed by the finely dispersed secondary α phase precipitated after heat treatment was the main reason for the increase of life by 3 times. The crack initiation was mainly due to the accumulation of Pyramidal < c + a > dislocations and base < a > dislocations. The difference was that, combined with molecular dynamics calculations and characterization by TEM and EBSD, it was found that the heat-treated cracks underwent dislocation accumulation, deformation twinning, and low-angle grain boundaries before the initiation of the lamellar α-concave position.
钛合金焊接结构在实际使用过程中经常受到复合波形和变幅的循环加载，加剧了接头的损伤，导致疲劳寿命低。因此，本研究采用了三阶段热处理来提高 TC4 钛合金脉冲激光-电弧混合焊接接头的疲劳寿命，并研究了其微观结构演变和断裂机理。结果表明，热处理后析出的细小分散的二次α相形成的高密度相界是寿命提高 3 倍的主要原因。裂纹的产生主要是由于金字塔位错（Pyramidal < c + a >）和基底位错（base < a >）的积累。不同之处在于，结合分子动力学计算以及 TEM 和 EBSD 表征，发现热处理裂纹在形成片状 α 凹陷位置之前经历了位错积累、变形孪晶和低角度晶界。
{"title":"Effect of three-stage heat treatment on the composite waveform and variable amplitude fatigue properties of TC4 titanium alloy pulsed laser-arc hybrid welded joints","authors":"Rui Su , Qianli Liu , Haizhou Li , Dirui Wang , Jinquan Guo , Shengbo Li , Wantong Wang , Aixin Feng , Zhongtao Sun , Hui Chen","doi":"10.1016/j.ijfatigue.2024.108673","DOIUrl":"10.1016/j.ijfatigue.2024.108673","url":null,"abstract":"<div><div>Titanium alloy welded structures are often subjected to cyclic loading with composite waveform and variable amplitude during actual service, exacerbating the damage to the joints and leading to low fatigue life. Therefore, a three-stage heat treatment was adopted in this work to enhance the fatigue life of TC4 titanium alloy pulsed laser-arc hybrid welded joints, and its microstructure evolution and fracture mechanism were investigated. The results show that the high-density phase boundary formed by the finely dispersed secondary α phase precipitated after heat treatment was the main reason for the increase of life by 3 times. The crack initiation was mainly due to the accumulation of Pyramidal < c + a > dislocations and base < a > dislocations. The difference was that, combined with molecular dynamics calculations and characterization by TEM and EBSD, it was found that the heat-treated cracks underwent dislocation accumulation, deformation twinning, and low-angle grain boundaries before the initiation of the lamellar α-concave position.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108673"},"PeriodicalIF":5.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-13DOI: 10.1016/j.ijfatigue.2024.108707
Zheng-Yu Mao , De-Guang Shang , Dao-Hang Li , Na-Min Xiao , Ai-Xue Sha , Jing-Xuan Li , Cheng Qian , Quan Zhou , Wen-Long Li
The fatigue experiments for titanium alloy Ti60 under different uniaxial/multiaxial thermo-mechanical loading modes found that the combined action of high temperature and tensile stress can cause the debonding of the second phase strengthening particles between grain boundary, reducing the ability to resist deformation of Ti60, which leads to a decrease in the fatigue life of the material. In addition, mean tensile stress increases the ability of cracks to break through intergranular barriers and the non-proportional additional hardening caused by multiaxial loading exacerbates the formation of microcracks. Both will increase the fatigue damage of the material. The fatigue damage mechanism identified in this investigation can reasonably explain the fatigue life law under multiaxial loading at high temperature, uniaxial and multiaxial thermo-mechanical fatigue loadings.
{"title":"Damage mechanisms of Ti60 under different uniaxial/multiaxial thermo-mechanical loading modes","authors":"Zheng-Yu Mao , De-Guang Shang , Dao-Hang Li , Na-Min Xiao , Ai-Xue Sha , Jing-Xuan Li , Cheng Qian , Quan Zhou , Wen-Long Li","doi":"10.1016/j.ijfatigue.2024.108707","DOIUrl":"10.1016/j.ijfatigue.2024.108707","url":null,"abstract":"<div><div>The fatigue experiments for titanium alloy Ti60 under different uniaxial/multiaxial thermo-mechanical loading modes found that the combined action of high temperature and tensile stress can cause the debonding of the second phase strengthening particles between grain boundary, reducing the ability to resist deformation of Ti60, which leads to a decrease in the fatigue life of the material. In addition, mean tensile stress increases the ability of cracks to break through intergranular barriers and the non-proportional additional hardening caused by multiaxial loading exacerbates the formation of microcracks. Both will increase the fatigue damage of the material. The fatigue damage mechanism identified in this investigation can reasonably explain the fatigue life law under multiaxial loading at high temperature, uniaxial and multiaxial thermo-mechanical fatigue loadings.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108707"},"PeriodicalIF":5.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.ijfatigue.2024.108705
Evan Wei Wen Cheok , Xudong Qian , Arne Kaps , Ser Tong Quek , Michael Boon Ing Si
This paper introduces a digital twin solution for corner fatigue crack growth assessment. The digital twin comprises three core features: (1) diagnosis, (2) prognosis and (3) updating. The diagnosis arm performs remote crack size measurement via strain data collected from strategically identified locations. The prognosis component postulates the fatigue life across both linear-elastic and elasto-plastic loading regimes through a fatigue crack growth power law with the cyclic J-integral, ΔJ, as the crack driving force. Uncertainty in power law parameters, however, may result in differences between the prognosis and observed fatigue life. Hence, the digital twin completes the feedback loop via Bayesian updating of the power law parameters, thereby mirroring its physical counterpart closely. An improved estimation of the remaining useful life follows. The proposed digital twin solution validates against three specimens under constant amplitude loading and a single specimen under variable amplitude loading. The successful application of the approach marks a significant step toward operational digital twins within practical settings.
{"title":"A strain-interfaced digital twin solution for corner fatigue crack growth using Bayesian inference","authors":"Evan Wei Wen Cheok , Xudong Qian , Arne Kaps , Ser Tong Quek , Michael Boon Ing Si","doi":"10.1016/j.ijfatigue.2024.108705","DOIUrl":"10.1016/j.ijfatigue.2024.108705","url":null,"abstract":"<div><div>This paper introduces a digital twin solution for corner fatigue crack growth assessment. The digital twin comprises three core features: (1) diagnosis, (2) prognosis and (3) updating. The diagnosis arm performs remote crack size measurement via strain data collected from strategically identified locations. The prognosis component postulates the fatigue life across both linear-elastic and elasto-plastic loading regimes through a fatigue crack growth power law with the cyclic <em>J</em>-integral, Δ<em>J</em>, as the crack driving force. Uncertainty in power law parameters, however, may result in differences between the prognosis and observed fatigue life. Hence, the digital twin completes the feedback loop via Bayesian updating of the power law parameters, thereby mirroring its physical counterpart closely. An improved estimation of the remaining useful life follows. The proposed digital twin solution validates against three specimens under constant amplitude loading and a single specimen under variable amplitude loading. The successful application of the approach marks a significant step toward operational digital twins within practical settings.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108705"},"PeriodicalIF":5.7,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The work is devoted into investigating the multiaxial low cycle fatigue behavior and constitutive model of 316L under various strain amplitudes, strain ratios, and phase angles at 550 °C. Experimental results show that both axial and shear stress amplitudes present three stages of cyclic hardening, softening and fracture. Internal stress analysis reveals that initial cyclic hardening is influenced by both friction and back stresses, while cyclic softening is primarily controlled by friction stress. Moreover, the Mises equivalent stress–strain relationship effectively accommodates different strain amplitudes and strain ratios, but cannot account for the non-proportional hardening arising from back stress. Pearson correlation analysis highlights a correlation between fatigue life and the equivalent stress amplitude and plastic strain energy density, and that elastic modulus is influenced by strain ratio and phase angle, not the strain amplitude. Based on the Chaboche unified viscoplastic constitutive theory, an improved constitutive model incorporating new hardening rules and Hooke’s law is proposed. In the proposed model, three classical loading path-dependent coefficients’ ability for description of non-proportional hardening and stiffness weakening behaviors are evaluated. Simulation results reveal that the proposed model can effectively capture the non-proportional hardening of back stress, stiffness weakening, non-masing effect, and varied softening rate.
这项工作致力于研究 316L 在 550 °C 下不同应变幅值、应变比和相位角条件下的多轴低循环疲劳行为和构成模型。实验结果表明，轴向应力和剪切应力振幅均呈现出循环硬化、软化和断裂三个阶段。内应力分析表明，初始循环硬化受摩擦应力和背应力的影响，而循环软化主要由摩擦应力控制。此外，米塞斯等效应力-应变关系能有效地适应不同的应变振幅和应变比，但无法解释背应力引起的非比例硬化。皮尔逊相关分析表明，疲劳寿命与等效应力振幅和塑性应变能量密度相关，弹性模量受应变比和相位角的影响，而不是应变振幅。在 Chaboche 统一粘塑性构成理论的基础上，提出了一种包含新硬化规则和胡克定律的改进构成模型。在提出的模型中，评估了三个经典的加载路径相关系数对非比例硬化和刚度减弱行为的描述能力。模拟结果表明，所提出的模型能有效捕捉反应力的非比例硬化、刚度减弱、非磨削效应和不同的软化率。
{"title":"Multiaxial low cycle fatigue behavior and constitutive model of 316L under various loading paths at high-temperature","authors":"Fei Liang, Wei Zhang, Qiaofa Yang, Peng Yin, Qixuan Zhang, Tianhao Ma, Le Chang, Changyu Zhou","doi":"10.1016/j.ijfatigue.2024.108708","DOIUrl":"10.1016/j.ijfatigue.2024.108708","url":null,"abstract":"<div><div>The work is devoted into investigating the multiaxial low cycle fatigue behavior and constitutive model of 316L under various strain amplitudes, strain ratios, and phase angles at 550 °C. Experimental results show that both axial and shear stress amplitudes present three stages of cyclic hardening, softening and fracture. Internal stress analysis reveals that initial cyclic hardening is influenced by both friction and back stresses, while cyclic softening is primarily controlled by friction stress. Moreover, the Mises equivalent stress–strain relationship effectively accommodates different strain amplitudes and strain ratios, but cannot account for the non-proportional hardening arising from back stress. Pearson correlation analysis highlights a correlation between fatigue life and the equivalent stress amplitude and plastic strain energy density, and that elastic modulus is influenced by strain ratio and phase angle, not the strain amplitude. Based on the Chaboche unified viscoplastic constitutive theory, an improved constitutive model incorporating new hardening rules and Hooke’s law is proposed. In the proposed model, three classical loading path-dependent coefficients’ ability for description of non-proportional hardening and stiffness weakening behaviors are evaluated. Simulation results reveal that the proposed model can effectively capture the non-proportional hardening of back stress, stiffness weakening, non-masing effect, and varied softening rate.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108708"},"PeriodicalIF":5.7,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142662784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present paper studies fatigue crack growth (FCG) produced by a load pattern obtained numerically in a simulation of trains crossing a real bridge. It uses a model where the cyclic plastic deformation is assumed to be the main damage mechanism and that cumulative plastic strain at the crack tip is the driving parameter for FCG. The accumulation of damage was found to be very irregular along each load block, the major part occurring in the overload region. Plasticity induced crack closure is relatively high due to the periodic application of overloads, playing a major role. The overload produces crack tip blunting, increasing the effective load range in subsequent load cycles. The maximum elastic load range was quantified and used to eliminate load cycles not producing fatigue damage, which is important to reduce the numerical effort. The comparison of Finite Element Model (FEM) predictions with NASGRO results, showed that this gives a non-conservative difference of 23% in the number of load cycles after 1 mm of crack growth.
{"title":"Fatigue crack growth due to spectrum load produced by trains in a bridge","authors":"D.M. Neto , T.A. Narciso , E.R. Sérgio , A.S. Cruces , P. Lopez-Crespo , F.V. Antunes","doi":"10.1016/j.ijfatigue.2024.108706","DOIUrl":"10.1016/j.ijfatigue.2024.108706","url":null,"abstract":"<div><div>The present paper studies fatigue crack growth (FCG) produced by a load pattern obtained numerically in a simulation of trains crossing a real bridge. It uses a model where the cyclic plastic deformation is assumed to be the main damage mechanism and that cumulative plastic strain at the crack tip is the driving parameter for FCG. The accumulation of damage was found to be very irregular along each load block, the major part occurring in the overload region. Plasticity induced crack closure is relatively high due to the periodic application of overloads, playing a major role. The overload produces crack tip blunting, increasing the effective load range in subsequent load cycles. The maximum elastic load range was quantified and used to eliminate load cycles not producing fatigue damage, which is important to reduce the numerical effort. The comparison of Finite Element Model (FEM) predictions with NASGRO results, showed that this gives a non-conservative difference of 23% in the number of load cycles after 1 mm of crack growth.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108706"},"PeriodicalIF":5.7,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663219","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}
Pub Date : 2024-11-08DOI: 10.1016/j.ijfatigue.2024.108701
Fuhao Deng , Zhao Wang , Yuanhao Wei
The ultra-high-strength engineering cementitious composites demonstrates pseudo strain hardening behavior when subjected to uniaxial tension, making it a promising material for enduring repeated or fatigue loads. Extensive research has been conducted on the quasi-static, dynamic, and fatigue behavior of this composites. However, due to the challenges of conducting direct tensile testing on concrete, investigations into the tensile fatigue behavior of ECC, particularly for ultra-high-strength ECC, remain limited. The fatigue behavior of concrete can be influenced by various factors. This study focuses on the impact of loading frequency. Several series of tensile fatigue tests were conducted under different loading frequencies and stress levels. The test results revealed that fatigue life increases with higher applied loading frequencies and decreases with increasing stress levels. The analysis of the test results includes the examination of failure modes, fatigue life, deformation, and secondary strain rates. A probabilistic model of fatigue failure, considering the discreteness of the initial static strength, was proposed based on the fatigue life. This model aligned well with the experimental results, providing valuable insights into the behavior of ultra-high-strength ECC under tensile fatigue conditions.
{"title":"Effect of loading frequency on tensile fatigue behavior of ultra-high-strength engineered cementitious composites","authors":"Fuhao Deng , Zhao Wang , Yuanhao Wei","doi":"10.1016/j.ijfatigue.2024.108701","DOIUrl":"10.1016/j.ijfatigue.2024.108701","url":null,"abstract":"<div><div>The ultra-high-strength engineering cementitious composites demonstrates pseudo strain hardening behavior when subjected to uniaxial tension, making it a promising material for enduring repeated or fatigue loads. Extensive research has been conducted on the quasi-static, dynamic, and fatigue behavior of this composites. However, due to the challenges of conducting direct tensile testing on concrete, investigations into the tensile fatigue behavior of ECC, particularly for ultra-high-strength ECC, remain limited. The fatigue behavior of concrete can be influenced by various factors. This study focuses on the impact of loading frequency. Several series of tensile fatigue tests were conducted under different loading frequencies and stress levels. The test results revealed that fatigue life increases with higher applied loading frequencies and decreases with increasing stress levels. The analysis of the test results includes the examination of failure modes, fatigue life, deformation, and secondary strain rates. A probabilistic model of fatigue failure, considering the discreteness of the initial static strength, was proposed based on the fatigue life. This model aligned well with the experimental results, providing valuable insights into the behavior of ultra-high-strength ECC under tensile fatigue conditions.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108701"},"PeriodicalIF":5.7,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.ijfatigue.2024.108700
Dariusz Skibicki , Aleksander Karolczuk
Multiaxial fatigue life prediction models rely on intrinsic parameters that provide the balance between arbitrary and reference stress/strain conditions. However, this balance may be compromised due to evolving damage mechanisms, causing initially determined model parameters to deviate from actual values, resulting in life prediction errors. Despite the significant impact of fatigue model parameters on prediction accuracy, this issue is often ignored, with many studies assuming constant parameters to simplify prediction algorithms and reduce computational costs. In this study, we introduce a novel approach to quantify the error introduced into fatigue life predictions by approximate methods for determining model parameters under multiaxial loading paths. For the first time, error estimation was conducted using a life-dependent method, revealing that the error is a function of the selected approximation method and the ratio of slope coefficients from S-N curves for torsional versus uniaxial loading. These findings provide a unique framework for selecting computationally efficient approximation methods while balancing life prediction accuracy. This balance is crucial in the design of metallic components using fatigue topology optimization and finite element analysis. The proposed methodology, validated across eight metallic materials subjected to various multiaxial loading paths, offers valuable insights into the trade-offs between computational cost and prediction accuracy, which are essential for optimized structural design.
{"title":"Error tolerance for effective model parameter estimation in multiaxial fatigue life prediction","authors":"Dariusz Skibicki , Aleksander Karolczuk","doi":"10.1016/j.ijfatigue.2024.108700","DOIUrl":"10.1016/j.ijfatigue.2024.108700","url":null,"abstract":"<div><div>Multiaxial fatigue life prediction models rely on intrinsic parameters that provide the balance between arbitrary and reference stress/strain conditions. However, this balance may be compromised due to evolving damage mechanisms, causing initially determined model parameters to deviate from actual values, resulting in life prediction errors. Despite the significant impact of fatigue model parameters on prediction accuracy, this issue is often ignored, with many studies assuming constant parameters to simplify prediction algorithms and reduce computational costs. In this study, we introduce a novel approach to quantify the error introduced into fatigue life predictions by approximate methods for determining model parameters under multiaxial loading paths. For the first time, error estimation was conducted using a life-dependent method, revealing that the error is a function of the selected approximation method and the ratio of slope coefficients from S-N curves for torsional versus uniaxial loading. These findings provide a unique framework for selecting computationally efficient approximation methods while balancing life prediction accuracy. This balance is crucial in the design of metallic components using fatigue topology optimization and finite element analysis. The proposed methodology, validated across eight metallic materials subjected to various multiaxial loading paths, offers valuable insights into the trade-offs between computational cost and prediction accuracy, which are essential for optimized structural design.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108700"},"PeriodicalIF":5.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.ijfatigue.2024.108696
Chenyu Du , Haitao Cui , Hongjian Zhang
An experiment was conducted to evaluate the creep-thermal fatigue (CTF) behavior of thin-walled structures with holes. To achieve this, a high-temperature hold phase was added in the testing. The crack propagation of CTF is driven by the combined effects of creep, thermal fatigue, and oxidation. Therefore, a creep-thermal fatigue-oxidation phase field model was developed to simulate CTF behavior. The model accounts for the interaction between creep damage and fatigue damage, as well as the oxidation effect. A creep degradation function was formulated based on classical damage theory, and two creep damage models were compared. Two physically meaningful strategies were proposed to describe oxidation-induced fatigue damage. Finally, the applicability of model to creep-fatigue was validated.
{"title":"Creep-thermal fatigue behavior of thin-walled structures with holes and a creep-thermal fatigue-oxidation phase field model","authors":"Chenyu Du , Haitao Cui , Hongjian Zhang","doi":"10.1016/j.ijfatigue.2024.108696","DOIUrl":"10.1016/j.ijfatigue.2024.108696","url":null,"abstract":"<div><div>An experiment was conducted to evaluate the creep-thermal fatigue (CTF) behavior of thin-walled structures with holes. To achieve this, a high-temperature hold phase was added in the testing. The crack propagation of CTF is driven by the combined effects of creep, thermal fatigue, and oxidation. Therefore, a creep-thermal fatigue-oxidation phase field model was developed to simulate CTF behavior. The model accounts for the interaction between creep damage and fatigue damage, as well as the oxidation effect. A creep degradation function was formulated based on classical damage theory, and two creep damage models were compared. Two physically meaningful strategies were proposed to describe oxidation-induced fatigue damage. Finally, the applicability of model to creep-fatigue was validated.</div></div>","PeriodicalId":14112,"journal":{"name":"International Journal of Fatigue","volume":"191 ","pages":"Article 108696"},"PeriodicalIF":5.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142663218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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