Engineering Fracture Mechanics最新文献_第7页

Effect of coarse aggregates on contact explosion resistance of concrete—A mesoscopic investigation 粗集料对混凝土抗接触爆炸性的影响--介观研究

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-19 DOI: 10.1016/j.engfracmech.2024.110576

Xiaopeng Qi , Jie Zhang , Anupoju Rajeev , Jian Liu , Zhiyong Wang , Zhifang Liu , Fengling Zhang , Zhihua Wang

The intricate relationship between the mechanical properties of concrete and its internal microstructure underscores the importance of comprehending explosion performance and damage mechanisms at a mesoscopic level to effectively enhance blast resistance. This study employed three-dimensional (3D) mesoscale models to numerically investigate the dynamic behavior of concrete mixed with coarse aggregates under contact explosion. Rigorous validation of numerical models and simulation techniques was untaken through the contact explosion tests. The study explored mesoscopic damage mechanisms in heterogeneous concrete targets with randomly distributed coarse aggregates, drawing comparisons with a homogeneous concrete target. Critical mesoscopic parameters influencing the contact explosion resistance of concrete were thoroughly examined. Structural effects of coarse aggregates emerge as pivotal, shifting the damage mode from overall failure with spalling-dominated damage in homogeneous concrete to localized failure in mesoscopic concrete. The mesoscopic concrete experienced a distinct four-stage damage evolution—cratering, crack initiation, perforation, and dynamic fragmentation—diverging from homogeneous concrete with multi-layer spalling originating from the boundaries. The exponential attenuation of shock waves observed in homogeneous concrete was locally disrupted by coarse aggregates in mesoscopic concrete, attributed to wave impedance mismatch and aggregate extrusion effects. Mortar strength primarily contributed to concrete cracking, with minimal impact on damage modes. Failure modes were predominantly influenced by the content and particle size of coarse aggregates. Higher volumetric fractions significantly reduced concrete spalling, while increased coarse aggregate size exacerbated perforation failure. This comprehensive study advances our understanding of blast-resistant concrete design at a mesoscopic level, providing valuable insights for strategies aimed at enhancing structural resilience.

混凝土的力学性能与其内部微观结构之间存在着错综复杂的关系，这凸显了在中观层面理解爆炸性能和破坏机制以有效提高抗爆性能的重要性。本研究采用三维（3D）中观模型对掺有粗骨料的混凝土在接触爆炸下的动态行为进行了数值研究。通过接触爆炸试验对数值模型和模拟技术进行了严格验证。研究探索了随机分布粗集料的异质混凝土目标的中观破坏机制，并与均质混凝土目标进行了比较。深入研究了影响混凝土抗接触爆炸性的关键中观参数。粗集料的结构效应至关重要，它将破坏模式从均质混凝土中以剥落为主的整体破坏转变为中观混凝土中的局部破坏。中观混凝土经历了截然不同的四阶段破坏演化--开裂、裂缝萌生、穿孔和动态碎裂--与匀质混凝土不同，中观混凝土的多层剥落源于边界。在均质混凝土中观察到的冲击波指数衰减在中观混凝土中被粗骨料局部破坏，这归因于波阻抗失配和骨料挤出效应。砂浆强度主要导致混凝土开裂，对破坏模式的影响微乎其微。破坏模式主要受粗骨料含量和粒径的影响。较高的体积分数可显著减少混凝土的剥落，而粗骨料粒径的增加则会加剧穿孔破坏。这项综合研究推进了我们对中观层面抗爆混凝土设计的理解，为旨在增强结构韧性的策略提供了宝贵的见解。

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引用次数: 0

Model for predicting type Ι fatigue crack growth rate in RKE field considering stress gradient 考虑应力梯度的 RKE 场中Ι型疲劳裂纹生长率预测模型

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-19 DOI: 10.1016/j.engfracmech.2024.110579

Fawang Lian , Juntai Hu , Jianhui Liu , Jianping Xu , Yangyang Zhao

Based on the stress–strain field at the crack tip of Rice-Kujawski-Ellyin (RKE) and considering the stress gradient effect near the crack tip of type I, a fatigue crack growth rate prediction model L-SG (RKE) for type I is proposed in this paper. Firstly, the stress gradient change value of 1 % at the crack tip is considered as the characteristic distance (stress gradient influence range), and the ratio of the equivalent stress to the far-field stress in the stress gradient influence range is defined as the stress gradient influence coefficient ρ; Secondly, the new model L-SG (RKE) is proposed to quantitatively describe the fatigue crack growth behavior by using the stress–strain field at the crack tip of RKE, and the stress gradient influence coefficient ρ is introduced, and then the crack tip passivation radius r_p is defined to eliminate the crack tip singularity, and the plastic strain energy failure criterion is combined.; Finally, the prediction effect of the L-SG (RKE) model is verified by 6 metal materials and the fatigue crack growth rate test results of 2 groups of 45 steel CT specimens, and compared with the SHI-CAI (RKE) model. At the same time, based on the R² fitting effect and the different requirements of the three stages of fatigue crack propagation, the prediction effect of the two prediction models is analyzed, and comprehensive evaluation from two aspects of safety and accuracy. The results show that the L-SG (RKE) prediction model can better reflect the actual fatigue crack propagation behavior, and can meet the requirements of practical engineering for the accuracy and safety of the prediction model. Especially, the prediction results of physical cracks in 45 steel shaft parts by this model agrees well with the experimental data.

本文以 Rice-Kujawski-Ellyin (RKE) 裂纹尖端的应力应变场为基础，考虑 I 型裂纹尖端附近的应力梯度效应，提出了 I 型疲劳裂纹生长率预测模型 L-SG (RKE)。首先，将裂纹尖端 1 % 的应力梯度变化值视为特征距离（应力梯度影响范围），并将应力梯度影响范围内的等效应力与远场应力之比定义为应力梯度影响系数 ρ；其次，提出新模型 L-SG (RKE)，利用 RKE 的裂纹尖端应力应变场定量描述疲劳裂纹生长行为，并引入应力梯度影响系数 ρ，然后定义裂纹尖端钝化半径 rp 以消除裂纹尖端奇异性，并结合塑性应变能失效准则。最后，通过 6 种金属材料和 2 组 45 个钢 CT 试件的疲劳裂纹生长率测试结果验证了 L-SG （RKE）模型的预测效果，并与 SHI-CAI （RKE）模型进行了比较。同时，基于 R2 拟合效果和疲劳裂纹扩展三个阶段的不同要求，分析了两种预测模型的预测效果，并从安全性和准确性两个方面进行了综合评价。结果表明，L-SG（RKE）预测模型能较好地反映实际疲劳裂纹扩展行为，能满足实际工程对预测模型准确性和安全性的要求。特别是该模型对 45 个钢轴零件物理裂纹的预测结果与实验数据吻合较好。

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引用次数: 0

Acoustic Emission characteristics and damage evolution of Concrete-Encased CFST columns under compressive load 抗压荷载下混凝土嵌入式 CFST 柱的声发射特性和损伤演变

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-19 DOI: 10.1016/j.engfracmech.2024.110578

Wei Shen , Hao Bai , Fei Wang , Cong Li , Fangzhu Du

Concrete-Encased Concrete Filled Steel Tubular (CE-CFST) is usually served as a compression member in engineering structures due to its high performance. It is crucial to reveal its compressive failure mechanism and the damage evolution law. This study used Acoustic Emission (AE) technology to monitor the compressive failure behavior of seven groups of CE-CFST columns with different diameter-width ratio, slenderness ratio and eccentricity, and then the AE signal characteristics and structural damage evolution law were discussed. Results show that the curve of AE characteristics can be used for effectively identifying the damage stages of CE-CFST structures. The failure process can be divided into six stages: initial compaction, stable growth of micro cracks, unstable propagation of macro cracks, collapsing of the outer RC structure, bulging of the core CFST structure and overall failure. The AE characteristic parameters, RA-AF value and b value are closely related to stress and crack of structure, and can be used for early warning of structural failure during the stage of unstable crack propagation. Particularly, the failure of outer concrete can be judged as b value drops to the minimum. The current study is of great significance for understanding the damage evolution process and achieving damage assessment of CE-CFST structures.

混凝土套筒混凝土填充钢管（CE-CFST）因其高性能，通常在工程结构中用作受压构件。揭示其抗压破坏机理和损伤演变规律至关重要。本研究采用声发射（AE）技术监测了 7 组不同径宽比、细长比和偏心率的 CE-CFST 柱的受压破坏行为，并探讨了 AE 信号特征和结构损伤演变规律。结果表明，AE 特性曲线可用于有效识别 CE-CFST 结构的破坏阶段。破坏过程可分为六个阶段：初始压实、微裂纹稳定增长、宏观裂纹不稳定扩展、外层 RC 结构坍塌、核心 CFST 结构隆起和整体破坏。AE 特性参数、RA-AF 值和 b 值与结构的应力和裂缝密切相关，可用于不稳定裂缝扩展阶段的结构破坏预警。特别是当 b 值降至最小值时，可判断外层混凝土的破坏。本研究对于理解 CE-CFST 结构的损伤演变过程和实现损伤评估具有重要意义。

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引用次数: 0

Experimental study on fracture properties of heat-treated granite in I-II mixed mode suffered from water and liquid nitrogen cooling methods 水和液氮冷却方法导致 I-II 混合模式热处理花岗岩断裂特性的实验研究

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-18 DOI: 10.1016/j.engfracmech.2024.110570

Yao Li , Lei Zhou , Xiaodong Xiao , Xian Liang , Haohan Wang , Hongdan Zhang , Bang Liu

Hot dry rock (HDR) development is significant for solving energy problems and realizing energy conservation and emission reduction. Liquid nitrogen (LN₂) fracturing and hydraulic fracturing can form cracks in the HDR and improve the efficiency of geothermal energy mining. Therefore, it is necessary to study the fracture characteristics of high-temperature granite under different cooling methods. In this study, the deterioration of the physical and mechanical properties of granite subjected to high-temperature treatment under water cooling and LN₂ cooling was studied. Two I/II mixed modes (tensile orientation mode and shear orientation mode) and a pure II mode fracture characteristics of cracked straight-through Brazilian disc (CSTBD) specimens made of granite were explored. The displacement and strain fields of cracked granite specimens were measured by using a digital image correlation (DIC) method. The results show that when the temperature is 25℃, 200℃, and 400℃, the loading angle and cooling method have a great influence on the fracture mechanical characteristics of the granite. In general, the increase of loading angle and LN₂ cooling will lead to the decrease of peak load. For example, at 200℃, β = 15°, the deterioration degree of water-cooled and LN₂-cooled specimens is 13.77 % and 16.69 %, respectively. When β = 23°, it increases to 14.62 % and 19.91 %, respectively. At the same time, an interesting phenomenon was found in the study. At 400℃, due to the Leidenfrost effect, the peak load of LN₂-cooled specimens was higher than that of water-cooled specimens, and the further increase of temperature weakened the effect. When the temperature is 600℃, the difference between the loading angle and the cooling method is weakened.

干热岩（HDR）开发对解决能源问题、实现节能减排意义重大。液氮（LN2）压裂和水力压裂可以在高温干岩体中形成裂缝，提高地热能开采效率。因此，有必要研究高温花岗岩在不同冷却方式下的断裂特征。在本研究中，研究了在水冷和 LN2 冷却条件下，经过高温处理的花岗岩的物理和机械性能的恶化情况。研究了花岗岩直通巴西圆盘（CSTBD）裂纹试样的两种 I/II 混合模式（拉伸取向模式和剪切取向模式）和纯 II 模式断裂特征。采用数字图像相关（DIC）方法测量了开裂花岗岩试样的位移和应变场。结果表明，当温度为 25℃、200℃ 和 400℃时，加载角度和冷却方式对花岗岩的断裂力学特性有很大影响。一般来说，加载角度和 LN2 冷却方式的增加会导致峰值载荷的降低。例如，在 200℃、β = 15° 时，水冷试样和 LN2 冷却试样的劣化程度分别为 13.77 % 和 16.69 %。当 β = 23° 时，恶化程度分别增加到 14.62 % 和 19.91 %。同时，研究还发现了一个有趣的现象。在 400℃时，由于莱顿弗罗斯特效应，LN2 冷却试样的峰值载荷高于水冷试样，而温度的进一步升高削弱了这种效应。当温度为 600℃时，加载角度与冷却方式之间的差异减弱。

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引用次数: 0

The field-enriched finite element method with gravity effects for simulating the cracking behaviors of large-scale engineering rock masses 用于模拟大型工程岩体开裂行为的重力效应现场富集有限元法

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-18 DOI: 10.1016/j.engfracmech.2024.110569

Xiaoping Zhou , Longfei Wang , Jinhui Zhang , Zheng Li , Yulin Zou

The field-enriched finite element method uses a scalar field defined as a field variable to describe cracks and characterize their impact on the displacement field and stress field of the solution model. It is capable of avoiding remeshing and employing level set functions to describe cracks when simulating the propagation of cracks. In this work, a field-enriched finite element model with gravity effects is proposed to simulate the large-scale failure process of engineering rock masses, and several numerical cases of geotechnical engineering are successfully analyzed. First, by introducing the unified tensile fracture criterion into the numerical model, the large-scale failure process of the intact slope is simulated. Second, the sliding process of rock slopes containing en echelon joints is numerically investigated. Third, the cracking process of the concrete dam is analyzed. Finally, the effects of joint and bedding plane inclination angles on the stability of tunnel chamber in transversely isotropic rock mass are studied. The numerical results indicate that the numerical method proposed in this work can accurately solve the large-scale failure process of rock masses.

场富集有限元法使用定义为场变量的标量场来描述裂纹，并描述裂纹对求解模型的位移场和应力场的影响。在模拟裂纹扩展时，它能够避免重网格化，并采用水平集函数来描述裂纹。本文提出了一种具有重力效应的场富集有限元模型来模拟工程岩体的大尺度破坏过程，并成功地分析了岩土工程中的几个数值案例。首先，通过在数值模型中引入统一拉伸断裂准则，模拟了完整边坡的大尺度破坏过程。其次，数值研究了含有梯形节理的岩石边坡的滑动过程。第三，分析了混凝土坝的开裂过程。最后，研究了节理和垫层平面倾角对横向各向同性岩体中隧道洞室稳定性的影响。数值结果表明，本文提出的数值方法可以精确地解决岩体的大规模破坏过程。

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引用次数: 0

Modelling of fracture-involved large strain behaviors of amorphous glassy polymers via a unified physically-based constitutive model coupled with phase field method 通过基于物理的统一构成模型和相场法模拟无定形玻璃态聚合物的断裂大应变行为

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-18 DOI: 10.1016/j.engfracmech.2024.110546

Kaixing Li , Hui Deng , Wujiao Xu , Yonggang Liu

To promote the application of amorphous glassy polymers in structural components, a reliable prediction of the deformation and the potential fracturing behaviors is in demand. This work aims to provide a simple and feasible computational method to analyze the large strain behaviors, including elasticity, viscoplasticity, and the subsequent fracture, of amorphous glassy polymers. This is achieved by incorporating a physically-based constitutive model coupled with the fracture phase field method into the commercial finite element software Abaqus/Explicit. Inside the constitutive model, shear-yielding, crazing, and disentangling are considered as the underlying mechanisms for viscoplastic deformation and damage initiation. It is noteworthy that a unified craze-initiation criterion with a clear physical meaning is proposed, distinguishing this work from the previous in the literature. Moreover, a relatively user-friendly numerical implementation is suggested by exploiting the built-in features of Abaqus/Explicit. Taking the typical amorphous glassy polymers for example, i.e., polycarbonate (PC) and poly-methyl-methacrylate (PMMA), various experiments from the literature have been simulated. The proposed approach has been validated, since an acceptable agreement between the simulated and experimental results is realized.

为了促进无定形玻璃态聚合物在结构部件中的应用，需要对其变形和潜在断裂行为进行可靠的预测。本研究旨在提供一种简单可行的计算方法，用于分析无定形玻璃态聚合物的大应变行为，包括弹性、粘塑性以及随后的断裂。为此，我们在商用有限元软件 Abaqus/Explicit 中加入了基于物理的构成模型和断裂相场方法。在该构成模型中，剪切屈服、龟裂和解理被视为粘塑性变形和损伤引发的基本机制。值得注意的是，本文提出了一个具有明确物理意义的统一开裂起始准则，使其有别于以往的文献。此外，通过利用 Abaqus/Explicit 的内置功能，提出了一种相对友好的数值实现方法。以典型的无定形玻璃聚合物（即聚碳酸酯（PC）和聚甲基丙烯酸甲酯（PMMA））为例，模拟了文献中的各种实验。由于模拟结果与实验结果之间达到了可接受的一致，因此所提出的方法得到了验证。

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引用次数: 0

A novel experimental method for studying rock collision 研究岩石碰撞的新型实验方法

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-17 DOI: 10.1016/j.engfracmech.2024.110542

Zong-Xian Zhang , Kasper Hahtonen , Liyuan Chi , Toochukwu Ozoji

This paper introduces a new experimental method for studying rock collision by making full use of the beauty of stress wave theory. In this method, a newly developed energy transmission component was placed between the gas gun and the transmitted bar of a split Hopkinson pressure bar (SHPB). The forementioned component consists of an incident bar which moves frictionlessly within a specified distance, a circular steel plate welded to the incident bar, and a support base which is bolted to the SHPB bed. A rock specimen is attached to the farther end of the incident bar. When the striker bar, propelled by the gas gun impacts the incident bar, a compressive stress wave is transmitted from the incident bar to the rock specimen. When the compressive wave arrives at the free end of the rock specimen, it is reflected into a tensile wave. Then when the pure stress becomes tensile and it is over the tensile strength of the glue at the interface between the rock specimen and the incident bar, the rock specimen is ejected, and then the ejected specimen will collide with the transmitted bar. During specimen flight, the velocity of the rock specimen can be measured by a laser instrument, while the remained energy transferred to the transmitted bar is measured by strain gauges attached to it. The process of rock specimen flight before collision and fragment flight after collision can be photographed using a high-speed camera. This experimental method can be used to not only study a collision between a moving rock and another object, but also imitate a drop weight test. By using this new method, seven rock collision tests were successfully conducted.

本文介绍了一种充分利用应力波理论研究岩石碰撞的新实验方法。在该方法中，在气枪和分体式霍普金森压力棒（SHPB）的传输棒之间放置了一个新开发的能量传输组件。上述组件包括一个在指定距离内无摩擦移动的入射杆、一个焊接在入射杆上的圆形钢板和一个用螺栓固定在分体式霍普金森压力棒基座上的支撑底座。入射杆的远端连接着岩石试样。当由气枪推动的击杆撞击入射杆时，压缩应力波会从入射杆传递到岩石试样。当压缩波到达岩石试样的自由端时，它被反射成拉伸波。当纯应力变成拉应力，并超过岩石试样和入射棒之间界面上胶水的拉伸强度时，岩石试样就会被弹出，然后弹出的试样会与传输棒相撞。在试样飞行过程中，岩石试样的速度可通过激光仪器测量，而传递到传输棒上的剩余能量则可通过其上的应变计测量。岩石试样在碰撞前的飞行过程和碰撞后的碎片飞行过程可以用高速照相机拍摄下来。这种实验方法不仅可以用来研究移动岩石与另一物体之间的碰撞，还可以用来模仿落重试验。利用这种新方法，成功地进行了七次岩石碰撞试验。

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引用次数: 0

Data-driven evaluation of the Paris’ law parameters in polyethylene pipe grades — Increasing the precision of fracture mechanical lifetime estimation 数据驱动的聚乙烯管材牌号巴黎定律参数评估 - 提高断裂机械寿命估算的精度

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-16 DOI: 10.1016/j.engfracmech.2024.110540

Mario Messiha , Johannes Wiener , Florian Arbeiter , Gerald Pinter

The Paris’ Law parameters

A

and

m

are a necessity for predicting lifetimes of structural components under static or fatigue loading that fail due to crack initiation and propagation. Conventional methods require measurements of crack growth kinetics that involve direct or indirect monitoring of physical crack extension during long-term experiments. Usually, measurement series also involve multiple specimens in order to obtain a crack growth controlled failure diagram of an investigated material under relevant load conditions. In this contribution a combination of simple numerical, statistical and analytical approaches is presented to obtain

A

and

m

without the need to measure actual crack growth. This is accomplished by reformulating the Paris’ Law to express

A

as a function of

m

. The parameter

m

is varied within a reasonable range to generate an analytical function for

A

that solves the equation of the Paris’ Law based lifetime for a single specimen. A subsequent superposition of all available specimens reveals an intersection of all

A

functions at the technically relevant pair of

A

and

m

values that are capable of describing the lifetime of all specimens with a minimum error. The obtained best-fitting

A

and

m

are in good agreement with literature and are able to predict the lifetime of previously published sample data based upon cyclic Cracked Round Bar test results with an average error of 3.30 ± 2.67%.

帕里斯定律参数 A 和 m 是预测静态或疲劳载荷下因裂纹产生和扩展而失效的结构部件寿命的必要条件。传统方法需要测量裂纹生长动力学，包括在长期实验中直接或间接监测物理裂纹扩展。通常情况下，测量系列还涉及多个试样，以便在相关载荷条件下获得受研材料的裂纹生长受控失效图。本文将结合简单的数值、统计和分析方法，在无需测量实际裂纹生长的情况下获得 A 和 m。参数 m 在合理范围内变化可生成 A 的分析函数，该函数可求解基于巴黎定律的单个试样寿命方程。随后对所有可用试样进行叠加，就会发现所有 A 函数在 A 和 m 的技术相关值对上的交集，该值能够以最小误差描述所有试样的寿命。所获得的最佳拟合 A 和 m 与文献资料十分吻合，能够预测基于循环裂纹圆棒测试结果的先前公布的样本数据的寿命，平均误差为 3.30 ± 2.67%。

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引用次数: 0

An advanced fast multipole dual boundary element method for analyzing multiple cracks propagation 用于分析多裂纹扩展的先进快速多极双边界元方法

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-16 DOI: 10.1016/j.engfracmech.2024.110547

Cong Li , Bin Hu , Zhongrong Niu , Yan Meng

A new fast multipole dual boundary element method (FMDBEM) is developed to analyze multiple crack propagations. To evaluate accurately the stress fields around the crack tip, a variable-order asymptotic element (VAE) is first proposed to express the singular behavior. This VAE is also suitable for the V-notches with different opening angles, requiring only minor adjustments of stress exponents. Then the VAE is introduced into the FMDBEM framework, where several singularity problems of integrals are solved. Finally, the FMDBEM with VAEs, combined with an adaptive scheme, is used to determine the crack propagation paths. Numerical examples show that the present method is accurate and easy to implement, making it an appealing tool for analyzing large complex structures that include randomly distributed cracks and notches.

本文开发了一种新的快速多极双边界元法（FMDBEM）来分析多裂纹扩展。为了准确评估裂纹尖端周围的应力场，首先提出了一种可变阶渐近元素（VAE）来表达奇异行为。这种 VAE 也适用于不同开口角度的 V 形缺口，只需对应力指数稍作调整即可。然后，将 VAE 引入 FMDBEM 框架，解决了积分的几个奇异性问题。最后，将带有 VAE 的 FMDBEM 与自适应方案相结合，确定裂纹扩展路径。数值示例表明，本方法准确且易于实施，是分析包含随机分布裂纹和缺口的大型复杂结构的理想工具。

引用次数: 0

Creep-to-rupture of T91 steel in static liquid lead-bismuth eutectic: Effects of cyclic temperature and oxygen environment 静态液态铅铋共晶中 T91 钢的蠕变到破裂：循环温度和氧气环境的影响

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-10-16 DOI: 10.1016/j.engfracmech.2024.110539

Zhikun Zhou , Chenwen Tian , Qun Zhang , Juan Du , Chuang Zhang , Hengjie Liu , Xing Gong , Magd Abdel Wahab , Ziguang Chen

The creep-to-rupture behavior of T91 steel in static liquid lead–bismuth eutectic (LBE) is investigated, focusing on the impacts of cyclic temperature and oxygen condition. The results indicate that thermal cycling, oxygen deficiency, and high applied stress levels significantly accelerate creep deformation and reduce the creep-to-rupture lifetime of T91 steel in LBE. Surface oxide scales on T91 steel and their self-healing mechanisms play a crucial role in enhancing the creep resistance by isolating the LBE contact and delaying crack initiation and propagation. However, the integrity of this oxide scale is compromised under cyclic thermal conditions and low oxygen levels, leading to premature failure. Microstructural examinations reveal the evolution of oxide scale damage and self-healing mechanisms. The findings suggest that oxide scale failure mechanisms should be considered when designing the long-term operational performance of advanced LBE-based reactors.

研究了 T91 钢在静态液态铅铋共晶（LBE）中的蠕变到脆化行为，重点是循环温度和氧气条件的影响。结果表明，热循环、缺氧和高外加应力显著加速了 T91 钢在 LBE 中的蠕变变形，并缩短了其蠕变脆化寿命。T91 钢表面的氧化鳞片及其自修复机制通过隔离 LBE 接触、延迟裂纹的产生和扩展，在增强抗蠕变性方面发挥了重要作用。然而，在循环热条件和低氧水平下，这种氧化鳞片的完整性会受到破坏，从而导致过早失效。微观结构检查揭示了氧化鳞片损坏的演变过程和自修复机制。研究结果表明，在设计基于 LBE 的先进反应堆的长期运行性能时，应考虑氧化鳞片的失效机制。

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引用次数: 0