International Journal of Fatigue最新文献_第6页

Blunt and sharp notches: Revisiting the limit notch radius via the averaged SED method and validating it against a wide fatigue strength reduction database 钝口和尖口：通过平均SED方法重新访问极限缺口半径，并根据广泛的疲劳强度降低数据库进行验证

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-19 DOI: 10.1016/j.ijfatigue.2026.109496

Pietro Foti , Michele Zappalorto , Filippo Berto

When designing mechanical components, their functional requirements often lead to geometrical discontinuities with severe stress concentrations and gradients. These discontinuities, known as notches, can markedly reduce the structural reliability and fatigue strength of components. Depending on the notch severity, conventional point-based approaches may significantly overestimate their detrimental effects on fatigue behaviour. Notches are generally classified as blunt or sharp with the fatigue behaviour of the sharp ones not accurately captured by point-based approaches. Numerous studies have attempted to define the transition between these two behaviour and to develop design methodologies capable of consistently addressing both. Among these, the averaged Strain Energy Density (SED) method has demonstrated high accuracy and robustness for both blunt and sharp notches. In this work, the SED method is employed to identify a limiting condition, expressed through a limit notch radius,

ρ_{limit}

, that distinguishes between blunt and sharp notches. This condition is investigated through numerical simulations and validated against an extensive fatigue database from the literature. Defining the limit condition as a notch radius simplifies components design and may also serve as guideline for determining the required notches tolerances. Finally, a methodology is proposed for fatigue-oriented material selection, coupling bulk material properties, component geometry and notch sensitivity. Indeed, in fatigue design, the highest-performing component is not necessarily obtained using the material with the highest intrinsic fatigue strength. For sharp notches, materials with lower intrinsic fatigue strength, but reduced notch sensitivity, can indeed yield superior fatigue performance. The methodology can be readily extended to lightweight design applications.

在设计机械部件时，其功能要求常常导致具有严重应力集中和梯度的几何不连续。这些被称为缺口的不连续性会显著降低构件的结构可靠性和疲劳强度。根据缺口的严重程度，传统的基于点的方法可能大大高估了它们对疲劳行为的有害影响。缺口一般分为钝的或锐的，锐的疲劳行为不能被基于点的方法准确捕获。许多研究试图定义这两种行为之间的转换，并开发能够始终解决这两种行为的设计方法。其中，平均应变能密度（SED）方法对钝切口和锐切口均具有较高的精度和鲁棒性。在这项工作中，SED方法被用来识别一个极限条件，通过一个极限缺口半径表示，ρ极限，区分钝和锋利的缺口。这种情况通过数值模拟进行了研究，并通过文献中广泛的疲劳数据库进行了验证。将极限条件定义为缺口半径可以简化零件的设计，也可以作为确定所需缺口公差的指南。最后，提出了一种面向疲劳的材料选择、耦合体材料特性、部件几何形状和缺口灵敏度的方法。事实上，在疲劳设计中，性能最高的部件不一定是使用具有最高固有疲劳强度的材料获得的。对于锋利的缺口，材料具有较低的固有疲劳强度，但降低缺口灵敏度，确实可以产生良好的疲劳性能。该方法可以很容易地扩展到轻量级设计应用程序。

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引用次数: 0

In-situ observations of cyclic deformation in an extruded Mg-2Nd-1Y-0.1Zr-0.1Ca alloy 挤压Mg-2Nd-1Y-0.1Zr-0.1Ca合金循环变形的原位观察

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-18 DOI: 10.1016/j.ijfatigue.2026.109489

Arianna Mena , Jiashi Miao , Daniel Veghte , Bruce Williams , Aeriel D. Murphy-Leonard

In this study, the evolution of deformation mechanisms during cyclic loading in an extruded, solution-treated Mg–2Nd–1Y–0.1Zr–0.1Ca alloy was investigated using a combination of in-situ loading, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and focused ion beam (FIB) nanofabrication. The initial microstructure exhibited a crystallographic texture where the c-axis were orie. Flat, rectangular dog-bone specimens were subjected to load-controlled, fully reversed fatigue for 50 cycles, during which the same region was sequentially mapped to track microstructural changes. After 10 cycles of loading deformation twins were observed. During tensile reloading detwinning or narrowing of those twinned regions occurred. After 20 cycles, detwinning ceased and residual twins remained in the material. SEM imaging revealed numerous surface slip traces after cyclic loading. EBSD-assisted slip trace analysis identified the activation of prismatic < a > and pyramidal < c + a > slip systems during low-cycle fatigue. Site-specific scanning transmission electron microscopy (STEM) further revealed that deformation was also accommodated by basal < a > slip and the dissociation of < c + a > dislocations. Center-of-symmetry (COS) analysis confirmed that the dissociation of < c + a > dislocations resulted in the formation of I₁ intrinsic stacking faults after cyclic loading. These findings provide new insights into the complex interplay of dislocation mechanisms governing fatigue deformation in rare-earth-containing Mg alloys.

本研究采用原位加载、扫描电子显微镜（SEM）、电子背散射衍射（EBSD）和聚焦离子束（FIB）纳米加工相结合的方法，研究了挤压、固溶处理Mg-2Nd-1Y-0.1Zr-0.1Ca合金在循环加载过程中的变形机制演变。初始微观结构表现为c轴偏纵的晶体织构。扁平的矩形狗骨试件经受载荷控制的完全反向疲劳50次，在此期间，同一区域被依次绘制以跟踪微观结构变化。在10次循环加载后，观察到变形孪晶。在拉伸再加载过程中，孪晶区域发生脱孪或缩窄。20次循环后，脱孪生停止，材料中仍有残留的孪晶。扫描电镜成像显示了循环加载后大量的表面滑动痕迹。EBSD-assisted滑痕量分析确定激活棱镜 & lt;  比; 和锥体 & lt; c +  祝辞 滑移系统在低循环疲劳。特定站点扫描透射电子显微镜(STEM)进一步显示,变形也适应了基底 & lt;  比; 滑的离解 & lt; c +  祝辞 混乱。对称中心（COS）分析证实，循环加载后， <； c + a >； 位错的解离导致I1本征层错的形成。这些发现为研究控制稀土镁合金疲劳变形的位错机制的复杂相互作用提供了新的见解。

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引用次数: 0

Understanding the bi-modal fatigue behavior of the case-hardened M50NiL steel 了解淬火M50NiL钢的双模态疲劳行为

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-16 DOI: 10.1016/j.ijfatigue.2026.109495

Aniclelson Raony Alves de Moura , Franck Morel , Etienne Pessard , Daniel Bellett , Louis Augustins , Damien Herisson

The gears used in aircraft engines are typically made from high-strength steels reinforced by thermochemical treatments (TCT). These treatments increase surface fatigue strength through microstructural modifications, enhancing hardness and adding compressive residual stresses. In some cases, the combination of material, TCT, and applied stress can lead to a bi-modal fatigue behavior, notably in failures at the gear tooth root. This work investigates the bi-modal fatigue response of M50NiL case-hardened steel by characterizing and analyzing crack initiation mechanisms to propose a relevant fatigue modeling approach. A comprehensive experimental fatigue test campaign was carried out on notched specimens under plane bending and on gear specimens using a Single Tooth Bending Fatigue (STBF) method. The resulting Wöhler diagram shows significant scatter in fatigue life for several stress levels, suggesting a bi-modal behavior with two distinct populations. Fractographic analyses confirmed the competition between two different crack initiation mechanisms depending on stress level and number of cycles to failure. A statistical analysis using a mixture model also indicates that a bi-modal distribution best represents the results. Accordingly, a probabilistic model is proposed to describe the bi-modal fatigue behavior from a global perspective, based on the maximum applied hot-spot surface stress for a fixed stress ratio. Finally, a complementary local stress analysis shows that the combined effect of stress and material property distributions significantly influences local maximum stress variation. Correcting for these factors reduces scatter in the bi-modal stress levels.

飞机发动机中使用的齿轮通常由高强度钢制成，经热化学处理（TCT）增强。这些处理通过改变微观组织、提高硬度和增加压残余应力来提高表面疲劳强度。在某些情况下，材料、TCT和施加应力的组合可能导致双峰疲劳行为，特别是在齿轮齿根处的失效。本文研究了M50NiL淬火钢的双模态疲劳响应，对裂纹起裂机制进行了表征和分析，提出了相应的疲劳建模方法。采用单齿弯曲疲劳法对缺口试件和齿轮试件进行了全面的平面弯曲疲劳试验。由此得出的Wöhler图显示了几种应力水平下疲劳寿命的显著分散，表明具有两个不同种群的双峰态行为。断口分析证实了两种不同的裂纹起裂机制之间的竞争，这取决于应力水平和失效循环次数。使用混合模型的统计分析也表明，双峰分布最能代表结果。因此，提出了一个基于固定应力比下热点表面最大应力的概率模型，从全局角度描述双峰疲劳行为。最后，互补的局部应力分析表明，应力和材料性能分布的共同作用对局部最大应力变化有显著影响。校正这些因素可减少双模态应力水平的分散。

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引用次数: 0

Near-threshold fatigue resistance of micrometer-grained steel welds: mechanisms and modeling 微米晶粒钢焊缝的近阈值抗疲劳：机理与建模

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-16 DOI: 10.1016/j.ijfatigue.2026.109494

Quan-Heng Yao, Rong Chen, Wen-Qing Lu, Xu-Yang Mo, Ming-Liang Zhu, Fu-Zhen Xuan

Materials with coarse grains are believed to have higher fatigue threshold with respect to damage tolerance design, in such a context, the mechanisms for fine grains governing fatigue crack propagation are not clear. In this study, the near-threshold fatigue crack propagation behavior of L907A steel welded joints with micrometer-size grains (∼2.5 μm) was investigated, and the associated damage mechanisms near crack-tip were analyzed. It was found that fine grains tended to have lower transition rate down to the near-threshold regime due to the interaction of cyclic plasticity and microstructures, which promoted the formation of nanovoids, nanograins, and amorphization near crack-tip. A modified Zhu-Xuan model was established by taking into account the local microhardness and stress ratios. These findings underscore the importance of grain size engineering in enhancing fatigue resistance and show promise for streamlining the fatigue threshold testing process, thereby reducing associated time and costs.

粗晶材料在损伤容限设计中被认为具有更高的疲劳阈值，在这种情况下，细晶控制疲劳裂纹扩展的机制尚不清楚。本文研究了L907A钢微米级（~ 2.5 μm）晶粒焊接接头的近阈值疲劳裂纹扩展行为，并分析了裂纹尖端附近的损伤机制。结果表明，由于循环塑性和微观组织的相互作用，细晶向近阈值区转变的速率较低，促进了裂纹尖端附近纳米孔洞、纳米晶粒的形成和非晶化。考虑了局部显微硬度和应力比，建立了修正的Zhu-Xuan模型。这些发现强调了晶粒尺寸工程在提高抗疲劳性能方面的重要性，并显示出简化疲劳阈值测试过程的希望，从而减少了相关的时间和成本。

引用次数: 0

Shear fatigue life prediction method for plug welded joints based on the equivalent structural stress model 基于等效结构应力模型的塞焊接头剪切疲劳寿命预测方法

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-15 DOI: 10.1016/j.ijfatigue.2026.109500

Long Yang , Xiao An , Wenyang Shao , Guangwu Yang , Bing Yang , Tao Zhu , Zhe Zhang

Fatigue fracture often occurs in plug welded joints under shear loads, but an accurate fatigue life evaluation method for this special type of joint has not yet been proposed. Therefore, the fatigue failure behavior of plug welded joints through extensive shear fatigue tests was investigated in this study. To this end, the fatigue failure process and failure modes of plug welded joints under shear loading were obtained, and F_a–N curves were established. The investigation revealed that the overall F_a–N curve exhibited poor correlation and did not satisfy the engineering requirements. Consequently, an equivalent structural stress model that accurately captures the stress state of plug welded joints using the coupled node loads as input conditions was derived. A beam-shell finite element (FE) model that can accurately simulate the stress distribution of the plug welded joint was subsequently established to obtain the load inputs for the model. The forces and moments of the coupled nodes extracted from the FE model were input into the equivalent structural stress model to obtain the equivalent structural stress σ_s of the plug welded joint. Finally, S_s–N and P–S_s–N curves normalized for different F_a–N curves were developed, and a shear fatigue life prediction method for plug welded joints based on the equivalent structural stress method was established. The accuracy of this method was verified through random vibration fatigue test. The findings of this study provide a reference for the structural design and life prediction of plug welded joints.

塞焊接头在剪切载荷作用下经常发生疲劳断裂，但目前还没有针对这种特殊类型的接头提出准确的疲劳寿命评估方法。因此，本研究通过广泛的剪切疲劳试验对塞焊接头的疲劳破坏行为进行了研究。为此，获得了塞焊接头在剪切载荷作用下的疲劳破坏过程和破坏模式，并建立了Fa-N曲线。调查发现，总体Fa-N曲线相关性较差，不满足工程要求。在此基础上，建立了以耦合节点荷载为输入条件的等效结构应力模型，该模型能准确地捕捉塞焊接头的应力状态。建立了能准确模拟塞焊接头应力分布的梁-壳有限元模型，得到了模型的载荷输入。将有限元模型中提取的耦合节点的力和弯矩输入到等效结构应力模型中，得到塞焊接头的等效结构应力σs。最后，建立了不同Fa-N曲线归一化后的Ss-N和P-Ss-N曲线，建立了基于等效结构应力法的塞焊接头剪切疲劳寿命预测方法。通过随机振动疲劳试验验证了该方法的准确性。研究结果可为塞焊接头的结构设计和寿命预测提供参考。

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引用次数: 0

Effects of chloride ion concentration on the LCF performance of 316L austenitic stainless steel in high-temperature pressurized water 氯离子浓度对316l奥氏体不锈钢高温加压水中LCF性能的影响

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-15 DOI: 10.1016/j.ijfatigue.2026.109490

Shizhuang Liu , Hongjun Yu , Shihan Man , Xun Zhang , Yaode Yin , Xiaoming Bai , Ziheng Tang , Licheng Guo

This investigation examines the influence of the chloride ion concentrations (0.05%–5%) on the low-cycle fatigue (LCF) behavior of 316L austenitic stainless steel (316L SS) under high-temperature pressurized water (HTPW) conditions. Experimental results indicate that chloride ions substantially decrease fatigue life, with maximum reductions reaching ∼55% relative to pure water conditions. To enable quantitative fatigue life assessment, a progressive modeling approach is developed and validated. Initially, the strain amplitude effect is incorporated into the environmental fatigue correction factor under pure water conditions. Building on this foundation, the effect of chloride ion concentration is introduced to establish a logarithmic predictive model that demonstrates accuracy across the 0.05%–5% range. Validation experiments at intermediate concentrations (0.3% and 3%) yield prediction errors within 10%. Analysis of the cyclic stress response (CSR) reveals that chloride addition shortens the peak stress saturation stage and accelerates stress degradation. Fractographic examination reveals that increasing chloride concentration accelerates fatigue degradation mechanisms, characterized by expanded fatigue striation spacing and increased oxide particle coarsening. These findings advance the mechanistic understanding of chloride-mediated corrosion fatigue. Overall, a logarithmic predictive model is proposed to predict the fatigue life of 316L SS in chloride-containing HTPW environments, with improved predictive accuracy for the 316L SS.

本文研究了氯离子浓度（0.05% ~ 5%）对316L奥氏体不锈钢（316L SS）在高温加压水（HTPW）条件下低周疲劳（LCF）行为的影响。实验结果表明，氯离子大大降低了疲劳寿命，与纯水条件相比，最大降幅可达55%。为了实现疲劳寿命的定量评估，开发并验证了一种渐进式建模方法。在纯水条件下，将应变幅值效应纳入环境疲劳修正系数。在此基础上，引入氯离子浓度的影响，建立了精度在0.05% ~ 5%范围内的对数预测模型。验证实验在中间浓度（0.3%和3%）下的产率预测误差在10%以内。循环应力响应分析表明，氯化物的加入缩短了峰值应力饱和阶段，加速了应力降解。断口分析表明，氯离子浓度的增加加速了疲劳降解机制，表现为疲劳条纹间距的扩大和氧化物颗粒粗化的增加。这些发现促进了对氯化物介导的腐蚀疲劳机理的理解。总体而言，提出了一种对数预测模型来预测316L SS在含氯化物HTPW环境中的疲劳寿命，提高了316L SS的预测精度。

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引用次数: 0

Fatal defect determination and nanotwin-assisted early damage in ultra-high cycle fatigue of additively manufactured titanium alloy 增材制造钛合金超高周疲劳致命缺陷确定及纳米孪晶辅助早期损伤

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-14 DOI: 10.1016/j.ijfatigue.2026.109491

MingHui Dai , Kun Yang , Xue Li , YaoHan Du , HaiTao Zhu , HongPing Zhang , JingJiang Wei , ChengLai Xin , QingYuan Wang

Additively manufactured (AM) titanium alloys have attracted wide attention due to their high specific strength and excellent corrosion resistance. However, fatal AM defect determination before fatigue loading and defect-induced early damage mechanism in the ultra-high cycle fatigue (UHCF) regime have been studied rarely. In this study, ultrasonic fatigue tests were carried out to study the UHCF behavior of AM Ti-6Al-4V (Ti64) alloy with low porosity (0.002 %). As a result, the difference in the crack initiation location doesn’t cause a significant difference in fatigue life. The lack of fusion defects are responsible for fatigue failure. Fatigue failure is not necessarily induced by the largest defect in size, but also depends on the location and shape of defects. The defect shape is considered to develop the new Y-parameter model, which can better predict fatigue life and determine the fatal defect before fatigue loading. During the early damage process, many {10–11} compressive nanotwins are generated, and which assist lath refinement to nanoparticles near the crack tip. Discontinuous intergranular microcracks prevail, microcrack evolution is accompanied by grain refinement.

增材制造钛合金因其高比强度和优异的耐腐蚀性而受到广泛关注。然而，对AM材料疲劳加载前致命缺陷的确定和超高周疲劳状态下缺陷诱发的早期损伤机制的研究却很少。通过超声疲劳试验研究了低孔隙率（0.002%）AM Ti-6Al-4V （Ti64）合金的UHCF行为。结果表明，裂纹起裂位置的差异不会导致疲劳寿命的显著差异。缺乏熔合缺陷是造成疲劳失效的主要原因。疲劳失效不一定是由最大缺陷的尺寸引起的，还取决于缺陷的位置和形状。考虑缺陷的形状，建立了新的y参数模型，该模型能较好地预测疲劳寿命，并在疲劳加载前确定致命缺陷。在早期损伤过程中，产生了许多{10-11}压缩纳米孪晶，这有助于板条细化到裂纹尖端附近的纳米颗粒。晶间微裂纹以不连续为主，微裂纹演化伴随着晶粒细化。

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引用次数: 0

Deterioration mechanism of the macroscopic properties and microstructure of concrete under low-temperature cyclic fatigue action 低温循环疲劳作用下混凝土宏观性能和微观结构劣化机理

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-14 DOI: 10.1016/j.ijfatigue.2026.109493

Liu Jin, Xiang Chen, Jieqiong Wu, Jian Yang, Xiuli Du

This study investigates the microstructural and macro-mechanical property degradation mechanisms of concrete subjected to low-temperature freeze–thaw cycles (LFC, –40 ℃ to 20 ℃) in four representative solutions (C₂H₆O₂ (ethylene glycol), H₂O, 3.5% NaCl, and 3.5% Na₂SO₄). The correlations between microstructures and macro-mechanical properties are analyzed with the aid of innovative techniques including vickers hardness, nanoindentation, etc. Results show that compared with the freeze–thaw with minimum temperature of almost –20 °C, LFC lead to more severe damage and alter the damage order as: 3.5% NaCl > 3.5% Na₂SO₄ > H₂O > C₂H₆O₂, originated from expansion effects including the water ice expansion, corrosion product expansion, and uneven expansion (or contraction) due to temperature gradients. Although the low-temperature expansion rates of 3.5% Na₂SO₄ and 3.5% NaCl solutions are lower than that of water, their damage is severe: the former involves synergistic damage from ice and ettringite expansion, while the latter is exacerbated by hysteretic low-temperature expansion and hygroscopicity of NaCl. Besides, LFC increase the porosity, the more-harmful pore proportion, porous phase, while decrease the nano-indentation elastic modulus of the cement matrix and the high-density C-S-H content with more severe damage to the cement matrix than the aggregates, leading to the concrete strength degradation. Furthermore, the strength damage is linearly correlated with the more-harmful pore proportion, vickers hardness damage, nano-indentation elastic modulus, but non-linearly related to the porosity, porous phase, and high-density C-S-H content.

研究了低温冻融循环（LFC, -40℃~ 20℃）下混凝土在四种代表性溶液（C2H6O2（乙二醇）、H2O、3.5% NaCl和3.5% Na2SO4）中的微观结构和宏观力学性能退化机理。利用维氏硬度、纳米压痕等新技术分析了合金的微观组织与宏观力学性能之间的关系。结果表明：与最低温度接近-20℃的冻融相比，LFC损伤更为严重，损伤顺序依次为：3.5% NaCl > 3.5% Na2SO4 > H2O > C2H6O2，其原因是水冰膨胀、腐蚀产物膨胀以及温度梯度引起的不均匀膨胀（或收缩）。虽然3.5% Na2SO4和3.5% NaCl溶液的低温膨胀率低于水，但其破坏程度较严重：前者是冰和钙矾石膨胀的协同破坏，后者是NaCl的滞后性低温膨胀和吸湿性加剧的破坏。此外，LFC增加了孔隙率、更有害的孔隙比例、多孔相，降低了水泥基体的纳米压痕弹性模量和高密度C-S-H含量，对水泥基体的损伤比骨料更严重，导致混凝土强度退化。强度损伤与更有害孔隙比例、维氏硬度损伤、纳米压痕弹性模量呈线性相关，而与孔隙率、多孔相和高密度C-S-H含量呈非线性相关。

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引用次数: 0

Multicondition fatigue behaviors of GH4169 alloy film cooling holes under thermo-mechanical coupling effects 热-力耦合作用下GH4169合金薄膜冷却孔的多工况疲劳行为

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-14 DOI: 10.1016/j.ijfatigue.2026.109492

Longqing Lei , Zhengqiu Zhang , Weibing Liu , Yuefei Luo , Wei Chen , Yangjie Zuo

The fatigue behavior of film cooling hole structures in hot-section components, particularly under thermo-mechanical coupling effects, is crucial for enhancing the durability and performance of gas turbines. This study investigates the fatigue performance of four typical film-cooling hole configurations (30° and 45° cylindrical holes (CH-30° and CH-45°), fan-shaped holes (FSH), and laidback fan-shaped holes (LFSH)) fabricated from the GH4169 alloy. A combined experimental and numerical approach was employed, examining the fatigue life and crack propagation under three temperature conditions: 25 °C, 500 °C, and 500 °C with coolant pass through the hole, which simulated the film cooling. The results demonstrate that fatigue life is significantly influenced by the geometry of the cooling holes and thermal environment. CH-30° consistently exhibited superior fatigue resistance across all temperature conditions. At 500 °C, the introduction of coolant notably improved fatigue life, especially for configurations such as LFSH, which showed an enhanced fatigue life compared to conventional shapes. The study also reveals that crack initiation and propagation predominantly occur at the upstream edge of the film holes, with significant variations in crack evolution mechanisms observed across different hole types and thermal conditions. This research provides a comprehensive understanding of the fatigue behavior of film-cooling hole structures with different thermal conditions and offers valuable insights into the optimization of hole geometries for improved fatigue resistance in high-temperature applications.

热截面部件的气膜冷却孔结构的疲劳性能，特别是在热-力耦合作用下的疲劳性能，对提高燃气轮机的耐久性和性能至关重要。研究了GH4169合金四种典型的气膜冷却孔结构（30°和45°圆柱孔（CH-30°和CH-45°）、扇形孔（FSH）和懒散扇形孔（LFSH））的疲劳性能。采用实验与数值相结合的方法，在25°C、500°C和500°C三种温度条件下，研究了冷却剂通过孔的疲劳寿命和裂纹扩展，模拟了膜状冷却。结果表明，冷却孔的几何形状和热环境对疲劳寿命有显著影响。CH-30°在所有温度条件下均表现出优异的抗疲劳性能。在500°C时，冷却剂的引入显著提高了疲劳寿命，特别是对于LFSH这样的配置，与传统形状相比，它的疲劳寿命得到了提高。研究还表明，裂纹的起裂和扩展主要发生在膜孔的上游边缘，不同孔类型和热条件下裂纹的演化机制存在显著差异。该研究提供了对不同热条件下气膜冷却孔结构疲劳行为的全面理解，并为优化孔几何形状以提高高温应用中的抗疲劳性提供了有价值的见解。

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引用次数: 0

From stress field to multiaxial fatigue life: A novel physics-guided neural network framework accounting for stress ratio, phase angle, and biaxiality ratio 从应力场到多轴疲劳寿命：一种新的物理导向神经网络框架，用于计算应力比、相位角和双轴比

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-13 DOI: 10.1016/j.ijfatigue.2026.109497

Amir Mohammad Mirzaei

Predicting the fatigue life under multiaxial loading is challenging because failure is governed by local stress fields and evolution of the stress state. The central idea of this study is to represent the geometric effect (including plain and notched configurations) by the spatial distributions of the three principal stresses in the potential region of failure, discretised over a set of nodes. Sampling these fields over one load cycle captures the loading history (stress ratio, biaxiality ratio, and phase angle) for constant-amplitude multiaxial loading, without introducing any additional ad hoc or phenomenological scalar damage parameter. To encode this loading history, a lightweight temporal Conv1D encoder is followed by a compact fully-connected regression head. The framework is validated on EN-GJS-600-3 using leave-one-case-out splits over 18 geometry–loading cases covering multiple geometries, axial, torsional, and multiaxial loading, three stress ratios, two biaxiality ratios, and three phase angles. Across this broad set, the model achieves R² = 0.70, while adding the nominal metadata increases the prediction accuracy to R² = 0.75. Compared with classical critical-plane benchmarks (SWT and FS), the proposed framework achieves higher accuracy and remains applicable to both plain and notched specimens, whereas critical-plane criteria degrade strongly when plain data are included (due to differences in the dominant failure mechanisms). Sensitivity analyses confirmed robustness to reasonable choices of spatial and temporal discretisation. Gradient-based saliency illustrates mechanistic insights: spatial importance concentrates at the notch tip, and temporal importance is dominated by the first principal-stress, consistent with tensile crack-opening and with SWT, which outperforms the shear-driven FS criterion.

多轴载荷下的疲劳寿命预测具有挑战性，因为失效受局部应力场和应力状态演变的控制。本研究的中心思想是通过在一组节点上离散的潜在破坏区域中的三个主应力的空间分布来表示几何效应（包括平原和缺口结构）。在一个加载周期内对这些场进行采样，可以捕获恒幅多轴加载的加载历史（应力比、双轴比和相位角），而无需引入任何额外的特殊或现象标量损伤参数。为了对这个加载历史进行编码，一个轻量级的临时Conv1D编码器后面跟着一个紧凑的全连接回归头。该框架在EN-GJS-600-3上进行了18种几何载荷工况的验证，包括多种几何载荷、轴向载荷、扭转载荷和多轴载荷、三种应力比、两种双轴比和三种相位角。在这个广泛的集合中，模型达到R2 = 0.70，而添加标称元数据将预测精度提高到R2 = 0.75。与经典的临界平面基准（SWT和FS）相比，所提出的框架具有更高的精度，并且仍然适用于普通和缺口样本，而当包含普通数据时，临界平面标准会严重退化（由于主要破坏机制的差异）。敏感性分析证实了对空间和时间离散化合理选择的鲁棒性。基于梯度的显著性说明了机理见解：空间重要性集中在缺口尖端，时间重要性由第一主应力主导，与拉伸裂缝张开和SWT一致，优于剪切驱动的FS准则。

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