International Journal of Fatigue最新文献_第6页

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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引用次数: 0

Microstructural evolution for enhanced high temperature fretting fatigue resistance in GH4169 via laser assisted ultrasonic surface rolling process 激光辅助超声表面轧制增强GH4169耐高温微动疲劳性能的组织演变

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-12 DOI: 10.1016/j.ijfatigue.2026.109487

Hao Zhang , Daoxin Liu , Jing Yang , Mengyao Li , Junnan Wu , Yueyang Li , Yanjie Liu , Yu Zhang , Xiaohua Zhang , Chang Ye

Laser assisted ultrasonic surface rolling process (LA-USRP) was applied to GH4169 superalloy to improve its high temperature fretting fatigue resistance. Conventional USRP increased the fretting fatigue life under axial tension–tension cyclic loading (stress ratio R = 0.1, frequency of 131 ± 2 Hz, maximum stress of 800 MPa, and contact pressure of 85 MPa) at 600 °C by a factor of 3.3, whereas LA-USRP achieved a 14.7-fold enhancement compared to the base material. This superior performance is primarily attributed to advantageous microstructural evolution, including a thicker gradient nanostructured surface layer (average surface grain size around 25 nm), higher compressive residual stresses (surface −2079 MPa, maximum −2443 MPa at around 35 μm depth), and the formation of refined nanotwins and stabilized 9R phase. These features significantly improve cyclic stability of compressive residual stresses (relaxation reduced from 89.6 % in USRP to 35.9 % in LA-USRP after fatigue) and impede dislocation motion at elevated temperatures. These findings offer a promising approach for enhancing the high temperature fretting fatigue performance of critical aero-engine components.

为提高GH4169高温合金的耐高温微动疲劳性能，采用激光辅助超声表面轧制工艺（LA-USRP）对其进行了加工。传统USRP在600 °C时，将轴向拉伸-拉伸循环加载（应力比R = 0.1，频率为131 ± 2 Hz，最大应力为800 MPa，接触压力为85 MPa）下的微动疲劳寿命提高了3.3倍，而LA-USRP则比基材提高了14.7倍。这种优异的性能主要归功于有利的微观结构演变，包括更厚的梯度纳米结构表面层（平均表面晶粒尺寸约为25 nm），更高的压缩残余应力（表面- 2079 MPa，深度约为35 μm时最大- 2443 MPa），以及精炼纳米孪晶和稳定9R相的形成。这些特征显著提高了压缩残余应力的循环稳定性（疲劳后松弛从USRP的89.6% %降低到LA-USRP的35.9% %），并阻碍了位错在高温下的运动。这些发现为提高航空发动机关键部件的高温微动疲劳性能提供了一条有希望的途径。

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引用次数: 0

Data-driven fatigue life prediction of corroded steel wires: A transfer learning on stacking interpretable model and feature sensitivity analysis 数据驱动的锈蚀钢丝疲劳寿命预测：基于叠加可解释模型和特征敏感性分析的迁移学习

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-12 DOI: 10.1016/j.ijfatigue.2026.109498

Tao Huang , Chunfeng Wan , Tingbin Liu , Yucheng Zhang , Xiangtao Lu , Youliang Ding , Hanwei Zhao , Changqing Miao , Songtao Xue

The study of the fatigue performance of corroded steel wires in bridge cables holds significant scientific value for advancing structural theory and informing engineering practice. To address key challenges in fatigue life prediction such as the scarcity of the complexity of nonlinear relationships and the lack of model interpretability, this study proposes a progressive solution framework consisting of integrated optimization, transfer validation, model interpretation, platform development. A dual-source heterogeneous database (A/B) was first constructed by integrating 422 sets of specimens data from the literature with 30 sets of experimental data obtained through independently conducted corrosion tests. An integration strategy based on stacked-transfer models is used to couple the strengths of six different machine learning (ML) models. The improved sparrow optimisation (ISSA) algorithm was employed for hyperparameter optimization. The results demonstrate that the proposed Stacking model surpasses both individual base learners and existing mathematical models from literature and specifications in prediction accuracy. When transferred to new independent datasets, the model maintains excellent predictive performance, validating its strong generalization capability. Furthermore, by incorporating the SHAP framework, the study systematically deciphers the model’s decision-making mechanism and quantifies the contribution distribution of individual parameters to fatigue life. Finally, to enhance model applicability, a web-based human–computer interaction platform for intelligent fatigue life prediction was developed based on the stacking-SHAP model. This study provides a data-algorithm-platform trinity solution for the whole life cycle management of bridge cables.

研究桥梁缆索腐蚀钢丝的疲劳性能，对于推进结构理论和指导工程实践具有重要的科学价值。针对疲劳寿命预测中非线性关系复杂性不足和模型可解释性不足等关键问题，本文提出了一个由集成优化、传递验证、模型解释和平台开发组成的渐进式解决方案框架。首先将文献中422组试样数据与独立进行腐蚀试验获得的30组实验数据进行整合，构建双源异构数据库（A/B）。采用基于堆叠迁移模型的集成策略，对六种不同机器学习模型的优势进行了耦合。采用改进的麻雀优化算法（ISSA）进行超参数优化。结果表明，本文提出的叠加模型在预测精度上优于单个基础学习器和现有文献和规范的数学模型。当转移到新的独立数据集时，该模型保持了良好的预测性能，验证了其强大的泛化能力。结合SHAP框架，系统解读了模型的决策机制，量化了各参数对疲劳寿命的贡献分布。最后，为了提高模型的适用性，开发了基于web的基于堆叠- shap模型的智能疲劳寿命预测人机交互平台。本研究为桥梁电缆全生命周期管理提供了数据-算法-平台三位一体的解决方案。

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引用次数: 0

Competing role of volumetric defects and microstructure on the fatigue behavior of additively manufactured Inconel 718: An experimental study 体积缺陷和微观组织对增材制造Inconel 718疲劳性能影响的实验研究

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-10 DOI: 10.1016/j.ijfatigue.2026.109486

Indrajit Nandi , Sajith Soman , Reza Molaei , Will Tilson , Nima Shamsaei , Shuai Shao

This study investigates the competing role of volumetric defects and microstructure on the fatigue behavior of additively manufactured Inconel 718 (IN718), with emphasis on the crack initiation mechanism. IN718 rods were fabricated using laser powder bed fusion with tuned process parameters and heat treatments to obtain diverse defect contents and microstructures. Both uniaxial tensile and fully-reversed, force-controlled fatigue tests were performed, and fractography was conducted to analyze various features observed at fatigue crack initiation sites. The influence of defects and microstructure was more pronounced on fatigue behavior than on tensile behavior. Both microstructure- and defect-mediated fatigue crack initiations were observed. For the former, facets were observed at the crack initiation sites which were due to the formation and operation of persistent slip bands. Interestingly, results revealed a similar dependence of fatigue life on the feature size at the crack initiation sites, regardless of the crack initiation mechanism.

本文研究了体积缺陷和微观组织对增材制造IN718疲劳性能的影响，重点研究了裂纹的起裂机理。通过调整工艺参数和热处理，采用激光粉末床熔合法制备了不同缺陷含量和显微组织的IN718棒。进行了单轴拉伸和完全反向力控制疲劳试验，并进行了断口分析，分析了疲劳裂纹萌生部位的各种特征。缺陷和显微组织对疲劳性能的影响大于对拉伸性能的影响。观察到微观组织和缺陷介导的疲劳裂纹萌生。对于前者，在裂纹起裂部位观察到由于持续滑移带的形成和作用而产生的切面。有趣的是，结果显示，无论裂纹起裂机制如何，疲劳寿命与裂纹起裂部位的特征尺寸有相似的依赖关系。

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引用次数: 0

Fatigue mechanisms and life prediction of cracked steel elements repaired with cold-expanded crack-stop holes 冷扩止裂孔修复裂纹钢构件的疲劳机理及寿命预测

IF 6.8 2区材料科学 Q1 ENGINEERING, MECHANICAL

International Journal of Fatigue

Pub Date : 2026-01-10 DOI: 10.1016/j.ijfatigue.2026.109484

Lu Ke , Youlin Li , Chuanxi Li , Xu Jiang , Jun Ye , Ailong Chen , Guojin Li

Fatigue cracks in steel elements repaired with traditional crack-stop holes are susceptible to perforation, enabling propagation and resulting in inadequate fatigue life improvement. The fatigue performance of cracked steel elements repaired by cold-expanded crack-stop holes was experimentally investigated, and the effects of cold expansion ratios and hole-to-crack tip distances on the fatigue life were examined. Finite element (FE) simulation tests were conducted to reveal the residual stress distributions around the crack-stop holes after cold expansion. The results show that higher cold expansion ratios significantly enhance fatigue life under an identical hole-to-crack tip distance. When the hole-to-crack tip distance was 0 mm, a cold expansion ratio of 2% yielded the greatest fatigue life improvement, with a 50.82% increase compared to specimens without cold expansion. Moreover, the residual stress was distributed nonlinearly along the thickness direction of the steel elements, with the peak residual stress occurring near the exit side of the cold expansion mandrel. Finally, based on the critical distance theory and residual stress weight allocation coefficient, a fatigue life prediction model for the crack initiation at the hole edges was developed. Simultaneously, based on linear elastic fracture mechanics, a fatigue life prediction model for the crack growth was proposed. The results indicated that the experimental and predicted values of the total fatigue life are in good agreement. This study offers a cold expansion technique for crack-stop holes, providing a novel technique for extending the fatigue life of cracked steel structures.

传统止裂孔修复钢构件疲劳裂纹容易穿孔，容易扩展，导致疲劳寿命提高不足。试验研究了冷扩止裂孔修复裂纹钢构件的疲劳性能，考察了冷扩比和孔-裂纹尖端距离对疲劳寿命的影响。通过有限元模拟试验，揭示了冷胀后止裂孔周围的残余应力分布。结果表明，在相同的孔-裂纹尖端距离下，较高的冷膨胀率显著提高了疲劳寿命。当孔-裂纹尖端距离为0 mm时，冷膨胀率为2%的试样疲劳寿命提高幅度最大，比未冷膨胀的试样疲劳寿命提高50.82% %。残余应力沿钢件厚度方向呈非线性分布，残余应力峰值出现在冷胀芯筒出口侧附近。最后，基于临界距离理论和残余应力权重分配系数，建立了孔边缘裂纹起裂疲劳寿命预测模型。同时，基于线弹性断裂力学，提出了裂纹扩展的疲劳寿命预测模型。结果表明，总疲劳寿命的实验值与预测值吻合较好。本研究提出了一种止裂孔的冷扩技术，为延长裂纹钢结构的疲劳寿命提供了一种新技术。

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