International Journal of Fatigue最新文献_第4页

Effect of water saturation on uniaxial constant amplitude tensile fatigue performance of ECC and its statistical analysis of fatigue life 水饱和度对 ECC 单轴恒幅拉伸疲劳性能的影响及其疲劳寿命统计分析

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-24 DOI: 10.1016/j.ijfatigue.2024.108666

Shuling Gao , Qingyuan Xu , Zhengwen Wang , Yanping Zhu

The degree of water saturation has a significant influence on the tensile fatigue properties of Engineered Cementitious Composites (ECC). The half-saturated and saturated state ECC can be rapidly prepared by a vacuum saturation equipment. The fatigue tensile mechanical tests under five tensile stress levels and corresponding studies on the damage morphology, fatigue life, S-N relationship, fatigue strain and fatigue damage on dry, half-saturated, and saturarted state were conducted. The mathematical and statistical analysis method was also utilized to predict ECC’s fatigue life and strength with high confidence and high reliability, providing a reference for assessing structural safety. The study found that free water significantly reduces ECC fatigue strength, with fatigue life decreasing as water content increases. At 2 million cycles, fatigue strength reduction coefficients for 0%, 50%, and 100% water saturation are 0.623, 0.550, and 0.423, respectively. The three-parameter Weibull distribution best describes ECC fatigue life. Using this model, S-N and P-S-N curves were developed, incorporating confidence limits to derive γ-P-S-N relationships, ensuring high confidence and reliability.

水饱和度对工程水泥基复合材料（ECC）的拉伸疲劳性能有重要影响。半饱和及饱和状态的 ECC 可通过真空饱和设备快速制备。在五个拉伸应力水平下进行了疲劳拉伸力学试验，并对干燥、半饱和和饱和状态下的损伤形态、疲劳寿命、S-N 关系、疲劳应变和疲劳损伤进行了相应的研究。并利用数理统计分析方法对 ECC 的疲劳寿命和强度进行了高置信度和高可靠性预测，为评估结构安全性提供了参考。研究发现，游离水会显著降低 ECC 的疲劳强度，疲劳寿命随着含水量的增加而降低。在 200 万次循环中，0%、50% 和 100% 水饱和度的疲劳强度降低系数分别为 0.623、0.550 和 0.423。三参数 Weibull 分布最能说明 ECC 的疲劳寿命。利用该模型，绘制了 S-N 和 P-S-N 曲线，并结合置信区间推导出 γ-P-S-N 关系，确保了高置信度和可靠性。

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引用次数: 0

High temperature fatigue behavior of coated and uncoated nickel-based single crystal superalloy DD6: Microstructures evolution, damage mechanisms and lifetime prediction 有涂层和无涂层镍基单晶超合金 DD6 的高温疲劳行为：微结构演变、损伤机制和寿命预测

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-24 DOI: 10.1016/j.ijfatigue.2024.108670

Jiaping Li, Xiaochao Jin, Dongxu Li, Jingjing Yang, Xueling Fan

Thermal barrier coatings (TBCs) are widely used to further extend the lifetime of turbine blades by protecting the blades from high temperature corrosion and oxidation. However, the mechanical behavior of turbine blades is obviously affected by the TBCs. In this study, microstructures evolution, damage mechanisms and life prediction of coated and uncoated nickel-based single crystal (NBSX) superalloy DD6 under isothermal fatigue load were investigated at 980 °C. The effects of TBCs on fatigue failure behavior and lifetime of DD6 were addressed. The results showed that the fatigue lifetime reduced with the increase of load. The effect of TBCs on the fatigue lifetime was related to the stress amplitude, as the effect was beneficial at high stress but almost negligible at low stress. Fracture morphologies showed that the cracks more likely initiated and propagated from basal defects for both coated and uncoated DD6, and the microstructure evolution also showed stress amplitude dependence. The crack density of uncoated DD6 increased first and then decreased with the increase of stress amplitude. However, the TBCs reduced the number of cracks that penetrate into the DD6 substrate, and the stress amplitude exerted a significant effect on crack propagation paths. In addition, the rafting behaviors of the DD6 substrate of coated and uncoated samples was compared, and results showed that TBCs could reduce the rafting degree of DD6. Finally, the fatigue lifetime of coated samples was predicted based on the modified Basquin model, and the prediction results fitted well with the experimental results.

热障涂层（TBC）通过保护叶片免受高温腐蚀和氧化，被广泛用于进一步延长涡轮叶片的使用寿命。然而，涡轮叶片的机械性能显然会受到热障涂层的影响。在本研究中，研究了在 980 °C 等温疲劳载荷下，涂覆和未涂覆镍基单晶 (NBSX) 超合金 DD6 的微观结构演变、损伤机理和寿命预测。研究探讨了 TBC 对 DD6 疲劳失效行为和寿命的影响。结果表明，疲劳寿命随着载荷的增加而缩短。TBC 对疲劳寿命的影响与应力幅值有关，因为在高应力下这种影响是有益的，而在低应力下几乎可以忽略不计。断裂形态显示，有涂层和无涂层 DD6 的裂纹更有可能从基底缺陷开始并扩展，而且微观结构的演变也与应力振幅有关。随着应力振幅的增大，未涂层 DD6 的裂纹密度先增大后减小。然而，TBC 减少了穿透 DD6 基材的裂纹数量，应力振幅对裂纹扩展路径有显著影响。此外，还比较了涂覆和未涂覆样品的 DD6 基底的筏化行为，结果表明 TBC 可降低 DD6 的筏化程度。最后，根据改进的 Basquin 模型预测了涂层样品的疲劳寿命，预测结果与实验结果吻合良好。

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引用次数: 0

MT-CrackNet:A multi-task deep learning framework for automatic in-situ fatigue micro-crack detection and quantification MT-CrackNet：用于原位疲劳微裂纹自动检测和量化的多任务深度学习框架

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-23 DOI: 10.1016/j.ijfatigue.2024.108667

Xiangyun Long, Hongyu Ji, Jinkang Liu, Xiaogang Wang, Chao Jiang

Characterizing fatigue micro-cracks is crucial for understanding the mechanisms and behaviors of material damage. In-situ fatigue testing is an essential method for observing the evolution of fatigue micro-cracks; however, the process often requires significant time, making the measurement of micro-cracks a tedious task. This paper introduces a multi-task deep learning framework called MT-CrackNet, which enables automatic detection and quantification of in-situ fatigue micro-cracks. The framework is capable of recognizing or segmenting multiple tasks such as micro-cracks, text, and scales simultaneously, and its effectiveness is not limited by the magnification of in-situ images. By integrating attention mechanisms and multi-scale strategies, the model enhances its ability to handle long-range dependencies and preserve detail information, accurately identifying and measuring the length of micro-cracks. The effectiveness of the proposed MT-CrackNet is validated through three in-situ fatigue micro-crack propagation experiments.

表征疲劳微裂纹对于了解材料损伤的机理和行为至关重要。原位疲劳测试是观察疲劳微裂纹演变的重要方法，但这一过程通常需要大量时间，因此测量微裂纹是一项繁琐的任务。本文介绍了一种名为 MT-CrackNet 的多任务深度学习框架，它可以自动检测和量化原位疲劳微裂纹。该框架能够同时识别或分割微裂纹、文本和尺度等多个任务，其有效性不受原位图像放大倍数的限制。通过整合注意力机制和多尺度策略，该模型增强了处理长距离依赖关系和保留细节信息的能力，从而准确识别和测量微裂缝的长度。通过三个原位疲劳微裂纹传播实验，验证了所提出的 MT-CrackNet 的有效性。

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引用次数: 0

Fatigue properties of non-press-fitted part of full-scale induction-hardened axles of medium-carbon steel for high-speed railway vehicles 高速铁路车辆用中碳钢全尺寸感应淬火车轴非压装部分的疲劳特性

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-21 DOI: 10.1016/j.ijfatigue.2024.108664

T. Makino , C. Kozuka , T. Hata , T. Kato , M. Yamamoto , K. Minoshima

This study aimed to examine the stress–number of cycles (S–N) curve and fatigue limit of non-press-fitted parts to improve the sophistication of the design method of induction-hardened axles for medium-carbon steel high-speed railway cars. Macroscopic cracks were generated in the non-press-fitted parts of the axles by selecting appropriate fatigue test methods. Thus, the S–N curve was approximated, and the fatigue limit was obtained. The value of an index in the power-law expression of the S–N curve was 11, which was proposed to fatigue damage evaluation standard. Moreover, we constructed a prediction model for high-and very-high-cycle fatigue limits based on the local fatigue-limit approach and fatigue test results of cut-out specimens from several depth regions of induction-hardened axles. The fatigue limit predicted by the model agrees with the experimental high-cycle fatigue limit. The model estimated that the fatigue limit did not decrease in the very-high-cycle regime.

本研究旨在研究非压配部件的应力-循环次数（S-N）曲线和疲劳极限，以提高中碳钢高速铁路车辆感应淬火车轴设计方法的先进性。通过选择适当的疲劳试验方法，在车轴的非压装部分产生了宏观裂纹。因此，对 S-N 曲线进行了近似，并得出了疲劳极限。在 S-N 曲线的幂律表达式中，一个指数的值为 11，并将其作为疲劳损伤评价标准。此外，我们还根据局部疲劳极限方法和感应淬火车轴多个深度区域切口试样的疲劳试验结果，构建了高循环和超高循环疲劳极限预测模型。该模型预测的疲劳极限与实验得出的高循环疲劳极限一致。模型估计，疲劳极限在极高循环状态下不会降低。

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引用次数: 0

Fatigue life prediction for Q420qFNH weathering steel welded joints considering the effect of multiple cracks 考虑多裂纹影响的 Q420qFNH 耐候钢焊接接头疲劳寿命预测

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-21 DOI: 10.1016/j.ijfatigue.2024.108665

Yan Ma , Chuang Cui , Qing-hua Zhang , Kun Tang , Zhen-yu Cheng

Multiple semi-elliptical cracks frequently develop at the weld toes of welded joints. These interfering multiple cracks significantly accelerate crack growth rates and reduce the fatigue life of a welded joint compared to a single crack. This study proposes a method for predicting the fatigue life of a welded joint with multiple cracks, considering weld toe amplification effect, multiple crack interference amplification effect, and crack closure effect. The method is validated through fatigue tests on Q420qFNH weathering steel welded joints. The main factors influencing the interference amplification effect are investigated, and theoretical formulas for the interference amplification factor of the stress intensity factor are derived using the finite element method and the superposition principle. The initiation, aggregation, and morphological evolution during the propagation process of multiple cracks is accurately simulated, and the fatigue life of both cruciform-welded and butt-welded joints is predicted. Additionally, a quantitative analysis is conducted to assess the impact of the number of fatigue cracks on fatigue strength. The results indicate that the interference amplification effect of cracks depends on their distance and mainly affects the surface point where the crack front is closest. The proposed fatigue life prediction method can accurately estimate the fatigue life of Q420qFNH steel welded joints considering the effect of multi-cracks. The interference and coalescence of multiple cracks significantly reduce the fatigue life of welded joints. An increase in the number of fatigue cracks notably decreases the fatigue strength.

在焊接接头的焊点处经常会出现多条半椭圆形裂纹。与单条裂纹相比，这些相互影响的多条裂纹大大加快了裂纹的生长速度，降低了焊点的疲劳寿命。本研究提出了一种预测多裂纹焊接接头疲劳寿命的方法，其中考虑了焊趾放大效应、多裂纹干涉放大效应和裂纹闭合效应。该方法通过 Q420qFNH 耐候钢焊接接头的疲劳试验进行了验证。研究了影响干涉放大效应的主要因素，并利用有限元法和叠加原理推导出了应力强度因子干涉放大系数的理论公式。精确模拟了多条裂纹在扩展过程中的萌发、聚集和形态演变，并预测了十字形焊接接头和对接焊接接头的疲劳寿命。此外，还进行了定量分析，以评估疲劳裂纹数量对疲劳强度的影响。结果表明，裂纹的干涉放大效应取决于裂纹的距离，主要影响裂纹前沿最近的表面点。考虑到多裂纹的影响，所提出的疲劳寿命预测方法可以准确估计 Q420qFNH 钢焊接接头的疲劳寿命。多裂纹的干涉和凝聚会显著降低焊接接头的疲劳寿命。疲劳裂纹数量的增加会明显降低疲劳强度。

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引用次数: 0

Corrosion and corrosion-fatigue properties of composite ceramic coated aluminum alloy formed by combining surface nanocrystallization pre-treatment, micro-arc oxidation, and sealing post-treatment 结合表面纳米结晶预处理、微弧氧化和密封后处理形成的复合陶瓷涂层铝合金的腐蚀和腐蚀疲劳性能

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-20 DOI: 10.1016/j.ijfatigue.2024.108661

Kaixin Su , Jiwang Zhang , Shengchuan Wu , Jinfa Guan , Hang Li , Dongdong Ji , Honglan Xie

The aluminum alloy components of the high-speed railway catenary, when exposed to the corrosive media in coastal regions, are confronted with a significant issue of corrosion-fatigue failure. Therefore, this study prepares a kind of composite ceramic coating formed by combining shot peening surface nanocrystallization pre-treatment, micro-arc oxidation (MAO) ceramic coating, and acrylic resin sealing post-treatment on 6082-T6 aluminum alloy used for high-speed railway catenary. Then, the corrosion and corrosion-fatigue properties of composite ceramic coated 6082-T6 aluminum alloy are investigated. Results indicate that the pre-treatment increases the thickness of ceramic coating, however results in larger internal defects connecting ceramic coating’s outer surface, leading to inferior corrosion resistance compared to plain ceramic coatings. However, owing to the presence of compressive residual stress and grain-refined layers within the substrate beneath the ceramic coating, ceramic coated specimens subjected to the pre-treatment exhibit superior corrosion-fatigue properties compared to plain coated specimens. Additionally, the post-treatment effectively reduces coating porosity and enhances corrosion resistance. In conclusion, the composite ceramic coating in this paper is demonstrated to exhibit a combination of superior corrosion resistance, fatigue and corrosion-fatigue properties.

高速铁路接触网的铝合金部件在沿海地区暴露于腐蚀性介质时，面临着严重的腐蚀疲劳失效问题。因此，本研究制备了一种由喷丸表面纳米结晶前处理、微弧氧化（MAO）陶瓷涂层和丙烯酸树脂密封后处理组合而成的复合陶瓷涂层，用于高速铁路接触网用 6082-T6 铝合金。然后，研究了复合陶瓷涂层 6082-T6 铝合金的腐蚀和腐蚀疲劳性能。结果表明，前处理增加了陶瓷涂层的厚度，但会导致陶瓷涂层外表面连接处的内部缺陷增大，从而导致耐腐蚀性能比普通陶瓷涂层差。然而，由于陶瓷涂层下的基体内部存在压缩残余应力和晶粒细化层，与普通涂层试样相比，经过前处理的陶瓷涂层试样表现出更优越的腐蚀疲劳性能。此外，后处理还能有效减少涂层孔隙率，提高耐腐蚀性能。总之，本文中的复合陶瓷涂层表现出了卓越的耐腐蚀性、疲劳性和腐蚀疲劳性能。

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引用次数: 0

Small fatigue crack behavior of CP-Ti in thin-walled cruciform specimens under biaxial loading 双轴加载下薄壁十字形试样中 CP-Ti 的微小疲劳裂纹行为

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-20 DOI: 10.1016/j.ijfatigue.2024.108662

Le Chang, Zhuowu Wang, Hongpeng Xie, Chao Lv, Wei Zhang, Changyu Zhou

This study investigates the small fatigue crack propagation behavior of commercially pure titanium (CP-Ti) using thin-walled cruciform specimens under in-plane biaxial loading, considering the effects of biaxial ratio and phase angle. Increasing phase angle results in more secondary cracks merging with main cracks perpendicular to the rolling direction (RD) and transverse direction (TD), a phenomenon attributed to the rise in shear stress that accelerates main crack growth. Higher loading biaxiality or a lower phase angle leads to decreased crack propagation rates and increased biaxial fatigue life. Electron backscatter diffraction (EBSD) analysis reveals that when the maximum normal stress aligns with the RD, prismatic slip primarily governs crack propagation, thereby accelerating crack propagation rates. Conversely, alignment with the TD reduces prismatic slip activity and crack propagation rates. Under equi-biaxial loading, prismatic slip activity decreases further, and crack propagation is dominated by multiple slip and twinning, consequently resulting in the slowest propagation rates. Additionally, a higher proportion of prismatic slip under high phase angle also accelerates crack propagation. Finally, incorporating Findley equivalent stress into the Chapetti model, which considers the crack length-dependent threshold effect, a highly accurate biaxial small fatigue crack propagation rate model is proposed.

本研究使用薄壁十字形试样研究了商用纯钛（CP-Ti）在平面双轴载荷下的微小疲劳裂纹扩展行为，并考虑了双轴比和相位角的影响。相位角的增加会导致更多的次裂纹与垂直于滚动方向（RD）和横向方向（TD）的主裂纹合并，这种现象归因于剪应力的增加加速了主裂纹的生长。加载双轴度越高或相位角越小，裂纹扩展率越低，双轴疲劳寿命越长。电子反向散射衍射（EBSD）分析表明，当最大法向应力与 RD 对齐时，棱柱滑移主要控制裂纹扩展，从而加快裂纹扩展速率。相反，与 TD 对齐时，棱柱滑移活动减少，裂纹扩展速率降低。在等轴向加载下，棱柱滑移活动进一步减少，裂纹扩展主要受多重滑移和孪生影响，因此扩展速率最慢。此外，高相位角下棱柱滑移比例较高也会加速裂纹扩展。最后，将 Findley 等效应力纳入 Chapetti 模型，考虑了与裂纹长度相关的阈值效应，提出了一个高度精确的双轴小疲劳裂纹扩展速率模型。

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引用次数: 0

Simulation of fatigue crack growth in aluminium alloy 7075-T7351 under spike overload and aircraft spectrum loading 模拟铝合金 7075-T7351 在尖峰过载和飞机频谱加载下的疲劳裂纹增长

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-20 DOI: 10.1016/j.ijfatigue.2024.108660

K.F. Walker , A. Grice , J.C. Newman Jr. , R. Zouev , S.A. Barter , D. Russell

The trend towards virtual testing and digital-twin assisted management means that the accurate and reliable simulation of fatigue crack propagation behaviour is more important than ever. Reliable but conservative approaches to support this are in widespread use in the aerospace industry. Nevertheless, the conservatism comes at a significant cost in terms of reduced structural life and an increased ongoing inspection requirement and, as such leads to questions about the economic burden of these approaches. Recent comparisons between blind predictions and test results revealed the extent of the issue for cracking in aluminium alloy 7075-T7351 coupons with configuration and loading representative of military transport aircraft wing skins. The current models were generally conservative by a factor of two or more in terms of crack propagation life. This suggested that there was significant scope to improve the modelling to better reflect all the complex contributing factors. The current work has investigated the issue of changes in the crack front constraint as the crack progresses from a state of high constraint (close to plane strain) to a lower constraint (approaching plane stress). This issue was investigated both experimentally and with the development of an improved analytical model. A test program was conducted on several specimens, loaded under constant-amplitude, constant-amplitude with spike-overloads and a variable amplitude spectrum. Crack-opening stress levels were measured at key points in the tests and the results were used to develop and evaluate improved modelling approaches. The improved model was generally able to predict crack growth within about ± 30 % of that demonstrated along with the correct form of the crack growth, which is a significant advance and will lead to reduced costs and increased safety.

虚拟测试和数字孪生辅助管理的发展趋势意味着对疲劳裂纹扩展行为进行准确可靠的模拟比以往任何时候都更加重要。可靠但保守的方法在航空航天工业中得到了广泛应用。然而，保守的代价是结构寿命的缩短和持续检查要求的增加，因此，这些方法的经济负担问题也随之而来。最近，盲目预测与测试结果之间的比较揭示了铝合金 7075-T7351 试样开裂问题的严重程度，其配置和载荷代表了军用运输机机翼蒙皮。就裂纹扩展寿命而言，目前的模型通常保守了两倍或更多。这表明模型还有很大的改进空间，以更好地反映所有复杂的影响因素。目前的工作研究了当裂纹从高约束状态（接近平面应变）发展到低约束状态（接近平面应力）时裂纹前约束的变化问题。该研究通过实验和开发改进的分析模型对这一问题进行了研究。对几个试样进行了测试程序，分别在恒定振幅、恒定振幅带尖峰过载和可变振幅频谱下加载。在测试的关键点测量了开裂应力水平，并利用测量结果开发和评估了改进的建模方法。改进后的模型一般能够预测裂纹的增长，其预测结果与正确的裂纹增长形式相差约 ± 30%，这是一项重大进步，将有助于降低成本和提高安全性。

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引用次数: 0

Fatigue behavior of additively manufactured 316L stainless steel: Competition between the effects of defects and microstructure 添加剂制造的 316L 不锈钢的疲劳行为：缺陷与微观结构效应之间的竞争

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-20 DOI: 10.1016/j.ijfatigue.2024.108658

Hugo Roirand , Anis Hor , Benoit Malard , Nicolas Saintier

Laser Powder Bed Fusion (LPBF) process, is becoming more and more widespread in industry. The possibilities of microstructural control offered by this process are an opportunity to study the contribution of the different length scales of microstructure to the fatigue behavior. This paper is devoted to the understanding of this fatigue behavior resulting from the interactions between the process induced defects and the different polycrystal length scales. Two distinct defect − microstructure competition regimes have been identified. The first concerns microstructures containing large Lack of Fusion (LoF) defects. These LoFs drastically reduce the fatigue life, while microstructure has no influence on the fatigue strength. The second regime concerns microstructures containing small defects. A limited effect of the polycrystalline microstructure was revealed. Furthermore, this paper demonstrates that the ratio between damage initiation defect size and grain size, used in literature to describe the defect and microstructure sensitivity of fatigue strength, is not applicable over a wide range of defects and microstructures, such as obtained by additive manufacturing processes. Finally, the comparison between the fatigue behavior of different microstructure and defect features shows that producing a finer microstructure improves fatigue strength despite the presence of a significant defect population.

激光粉末床熔融（LPBF）工艺在工业中的应用越来越广泛。这种工艺提供的微观结构控制可能性为研究不同长度尺度的微观结构对疲劳行为的影响提供了机会。本文致力于了解这种疲劳行为是由工艺诱导的缺陷和不同多晶体长度尺度之间的相互作用引起的。本文确定了两种不同的缺陷--微结构竞争机制。第一种情况是微结构中含有大的熔合缺陷（LoF）。这些 LoF 大幅降低了疲劳寿命，而微结构对疲劳强度没有影响。第二种情况涉及含有小缺陷的微结构。多晶微结构的影响有限。此外，本文还证明了文献中用来描述疲劳强度的缺陷和微结构敏感性的损伤起始缺陷尺寸和晶粒尺寸之间的比率不适用于广泛的缺陷和微结构，例如通过增材制造工艺获得的缺陷和微结构。最后，不同微结构和缺陷特征的疲劳行为比较表明，尽管存在大量缺陷，但制造更精细的微结构可提高疲劳强度。

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引用次数: 0

A novel prediction method for rolling contact fatigue damage of the pearlite rail materials based on shakedown limits and rough set theory with cloud model 基于抖动极限和粗糙集理论与云模型的珠光体轨道材料滚动接触疲劳损伤预测新方法

IF 5.7 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2024-10-19 DOI: 10.1016/j.ijfatigue.2024.108654

Yulong Xie , Haohao Ding , Zhiyong Shi , Enrico Meli , Jun Guo , Qiyue Liu , Roger Lewis , Wenjian Wang

Evaluation and prediction of wheel-rail rolling contact fatigue (RCF) damage can provide important theoretical guarantees for the service safety of wheels and rails and help make maintenance easier to plan. This study aims to develop a novel method for evaluating and predicting RCF damage of the pearlite rail materials with various initial shear yield strengths (k_e). Based on the rough set mathematical theory incorporated within the cloud model of the comprehensive evaluation index (P₀/k_e*μ^t), a novel evaluation and prediction method for RCF damage states of various pearlite rail materials was constructed using the shakedown limits for pearlite rail materials with various initial shear yield strengths. To develop this novel prediction method, different evaluation indices for RCF damage states were designed. A comprehensive certainty approach was introduced to quantitatively analyze the actual measured values of distinct evaluation indices that corresponds to different RCF damage states, wherein the maximum value rule was applied. Moreover, the prediction results were confirmed after further verifying using the actual measured value of the P₀/k_e*μ^t. The results indicated that the predicted results were consistent with the test outcomes. The key feature of this prediction method was that it involved both the intrinsic shear yield strength of evaluated pearlite rail materials and wheel-rail rolling contact variables. On the basis of the two-dimensional classical shakedown map, a three-dimensional shakedown limit diagram for rail materials with varying initial shear yield strengths was further constructed using this novel prediction method. The three-dimensional shakedown limit diagram featured an inclined curved surface. As the initial shear yield strength of the pearlite rail materials increased, the curved surface tilted downward, indicating that an increase in the initial k_e value of the pearlite rail materials could result in a lower shakedown limit.

轮轨滚动接触疲劳（RCF）损伤的评估和预测可为车轮和钢轨的使用安全提供重要的理论保障，并有助于使维护计划更容易制定。本研究旨在开发一种新方法，用于评估和预测具有不同初始剪切屈服强度（ke）的珠光体钢轨材料的 RCF 损伤。基于综合评价指数（P0/ke*μt）云模型中包含的粗糙集数学理论，利用具有不同初始剪切屈服强度的珠光体钢轨材料的晃动极限，构建了一种新型的评价和预测各种珠光体钢轨材料 RCF 损伤状态的方法。为了开发这种新型预测方法，设计了不同的 RCF 损伤状态评价指标。引入了一种综合确定性方法来定量分析与不同 RCF 损伤状态相对应的不同评价指数的实际测量值，其中应用了最大值规则。此外，还利用 P0/ke*μt 的实际测量值进一步验证了预测结果。结果表明，预测结果与测试结果一致。这种预测方法的主要特点是，它同时涉及被评估的珠光体钢轨材料的内在剪切屈服强度和轮轨滚动接触变量。在二维经典晃动图的基础上，利用这种新颖的预测方法进一步构建了不同初始剪切屈服强度钢轨材料的三维晃动极限图。三维晃动极限图是一个倾斜的曲面。随着珠光体钢轨材料初始剪切屈服强度的增加，弧面向下倾斜，表明珠光体钢轨材料初始柯值的增加可导致较低的晃动极限。

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引用次数: 0