Theoretical and Applied Fracture Mechanics最新文献_第4页

Research on the mechanical anisotropy and crack propagation in composite rock masses containing weak interlayers and double fissures 含弱夹层双裂隙复合岩体力学各向异性及裂纹扩展研究

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-01-22 DOI: 10.1016/j.tafmec.2026.105471

Mingchao Wan , Nan Yao , Binyu Luo , Zheng Wan , Yicheng Ye

Layered rock masses, as complex geological media, exhibit mechanical behaviors predominantly controlled by internal weak interlayers and inherent fissures. This study aims to reveal the anisotropic characteristics of the mechanical behavior of layered rock masses under the interaction between weak interlayers and fissures. Uniaxial compression tests were conducted on rock-like specimens containing weak interlayers and prefabricated double fissures, combined with Digital Image Correlation (DIC) and Acoustic Emission (AE) monitoring techniques, to analyze the damage evolution process and the mechanical mechanisms of crack propagation. The results indicate that: (1) The initiation and propagation of tensile wing cracks at the fracture tips exhibit a strong competitive advantage, which weakens as the bedding dip angle increases. (2) The rock bridge serves as a key area for stress concentration and is influenced by the bridging angle β, governing the type of dominant cracks and the pattern of coalescence. (3) The weak interlayer significantly alters the interlayer stress field, inducing cracks to initiate vertically to the interlayer interface or to deflect, while demonstrating typical “barrier” and “guiding” dip effects on tip cracks. (4) The failure mode of the rock mass is primarily characterized by composite failure involving tensile cracking at the tips and penetration through the weak interlayer and hard rock layers. The propagation path is jointly influenced by the fracture dip angle, bridging angle, and the activation state of interlayer shear slip. This study reveals that when the double fissure layout (rock bridge dip angle) is oriented opposite to the dip direction of the weak interlayer, the pillar system is most susceptible to penetrating shear instability failure. Meanwhile, an increase in the bedding dip angle promotes slip along the weak interlayer, which reduces mechanical anisotropy and results in lower overall strength. These findings provide a theoretical reference for optimizing the layout and targeted support design of pillars in multi-layered stratified ore bodies, such as phosphate mines.

层状岩体作为复杂的地质介质，其力学行为主要受内部软弱夹层和固有裂隙的控制。本研究旨在揭示弱夹层与裂隙相互作用下层状岩体力学行为的各向异性特征。对含弱夹层和预制双裂纹的类岩试件进行单轴压缩试验，结合数字图像相关（DIC）和声发射（AE）监测技术，分析损伤演化过程和裂纹扩展的力学机制。结果表明：(1)断裂尖端张拉翼裂纹的萌生和扩展表现出较强的竞争优势，随着层理倾角的增大，这一优势减弱；(2)岩桥是应力集中的关键区域，受桥角β的影响，控制着主裂缝的类型和贯通方式。(3)弱夹层显著改变了层间应力场，诱导裂纹沿层间界面垂直起始或偏转，而对尖端裂纹表现出典型的“屏障”和“导向”倾斜效应。(4)岩体破坏模式主要表现为尖端拉裂、穿透弱夹层和硬岩层的复合破坏。裂缝倾角、桥接角和层间剪切滑移激活状态共同影响裂缝的传播路径。研究表明，当双裂隙布置（岩桥倾角）与弱夹层倾角方向相反时，矿柱体系最容易发生穿透剪切失稳破坏。同时，随着顺层倾角的增大，沿弱夹层滑移加剧，力学各向异性降低，整体强度降低。研究结果为磷矿等多层层状矿体中矿柱的优化布置和针对性支护设计提供了理论参考。

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引用次数: 0

A review on the fracture of brittle and quasi-brittle materials using semi-circular bend (SCB) tests 半圆弯曲试验对脆性和准脆性材料断裂的研究进展

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-02-07 DOI: 10.1016/j.tafmec.2026.105501

Mahinda Kuruppu , Majid R. Ayatollahi , Ken P. Chong

The semi-circular bend (SCB) specimen was originally suggested and developed for testing mode I fracture toughness of rock and other brittle or quasi-brittle materials. Since its introduction, the SCB test has been improved and extended for many other applications. Among them were its suitability for testing mixed mode I and II fracture that has a great deal of practical significance, its adaptability for testing dynamic fracture properties of materials and its applicability to testing a wide variety of materials including asphalt concrete mixes, polymer, nano and bio composites, additively manufactured and smart materials. Recent research findings on the use of appropriate loading and support pins, and the development of the methods to address the specimen size dependence of fracture toughness have enhanced the accuracy of test results. Methods of correction suggested by a number of researchers which enable one to determine a scale independent Mode I fracture toughness using the experimental results are discussed. Following the development of ISRM suggested method for fracture toughness determination of rock materials using the SCB specimen in 2014, four other standards including ASTM to determine the fracture toughness and other related properties of asphalt concrete were developed and their advantages and limitations are discussed.

半圆弯曲（SCB）试样最初是为测试岩石和其他脆性或准脆性材料的I型断裂韧性而提出和发展的。自推出以来，SCB测试已经得到了改进和扩展，适用于许多其他应用。其中，适合于测试具有重要实际意义的I型和II型混合断裂，适合于测试材料的动态断裂性能，适用于测试沥青混凝土混合料、聚合物、纳米和生物复合材料、增材制造和智能材料等多种材料。近年来，在使用合适的加载和支撑销方面的研究成果，以及解决断裂韧性对试样尺寸依赖的方法的发展，提高了测试结果的准确性。讨论了一些研究人员提出的校正方法，这些方法使人们能够根据实验结果确定与尺度无关的I型断裂韧性。继2014年ISRM建议的用SCB试样测定岩石材料断裂韧性的方法发展之后，又发展了ASTM等测定沥青混凝土断裂韧性等相关性能的四个标准，并讨论了它们的优点和局限性。

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引用次数: 0

Shear capacity of reinforced recycled aggregate concrete: Roles of fracture-surface roughness and matrix strength 钢筋再生骨料混凝土抗剪承载力：裂缝表面粗糙度和基体强度的作用

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-02-07 DOI: 10.1016/j.tafmec.2026.105498

Sourav Chakraborty , Kolluru V.L. Subramaniam

Recycled coarse aggregate (RCA) has gained popularity as a sustainable alternative to natural aggregate (NA) in concrete. However, for RCA to be widely adopted in structural applications, it is crucial to develop a thorough understanding of its behavior under various loading conditions. In particular, attention must be paid to the mechanisms governing failure and to the capacity of recycled aggregate concrete (RAC) under brittle failure modes. Two critical scenarios in this context are mode-I fracture, which is associated with tensile cracking, and flexure-shear loading conditions, which often dictate the ultimate strength and serviceability of reinforced concrete members. This paper investigates cracking under mode-I fracture and failure under flexure-shear loading in RAC for two different concrete matrix strengths. While RAC exhibited lower mechanical strengths than natural aggregate concrete (NAC), the 3D mapping of crack profiles revealed that shear performance is dictated by crack morphology. Increasing the matrix strength produces rougher crack surfaces in RAC, enhancing stress transfer. The progression of flexure-shear cracks is analyzed using digital image correlation (DIC). The failure is identified with a loss of shear stress transfer across the primary shear crack. Tensile strength (f_t), represented by the square root of compressive strength, does not capture the observed variation in the shear capacity in RAC. This study demonstrates that the reduced crack roughness in RCA results in an overall reduction in flexure-shear capacity in lower-strength mixes, while increased roughness offsets reduced tensile strength in higher-strength RAC. Consequently, compressive-strength-based conventional design criteria provide an inconsistent margin of safety because crack roughness is not accounted for. Design equations for consistent safety need to consider surface roughness as an input variable.

再生粗骨料（RCA）作为混凝土中天然骨料（NA）的可持续替代品而受到欢迎。然而，为了在结构应用中广泛采用RCA，深入了解其在各种载荷条件下的行为是至关重要的。特别是，必须注意控制破坏的机制和再生骨料混凝土（RAC）在脆性破坏模式下的能力。在这种情况下，两种关键情况是i型断裂，这与拉伸开裂有关，以及弯曲-剪切加载条件，这通常决定了钢筋混凝土构件的极限强度和使用能力。本文研究了两种不同混凝土基体强度下RAC型断裂开裂和弯剪荷载下的破坏。虽然RAC表现出比天然骨料混凝土（NAC）更低的机械强度，但裂缝剖面的三维映射显示，剪切性能由裂缝形态决定。在RAC中，增加基体强度会使裂纹表面变得粗糙，从而增强应力传递。利用数字图像相关（DIC）分析了弯剪裂纹的演化过程。破坏是通过主剪切裂缝上剪切应力传递的损失来确定的。抗拉强度（ft），由抗压强度的平方根表示，不能捕获在RAC中观察到的剪切能力变化。该研究表明，在低强度混合料中，RCA中裂纹粗糙度的降低导致弯曲-剪切能力的整体降低，而在高强度RAC中，粗糙度的增加抵消了抗拉强度的降低。因此，基于抗压强度的传统设计标准提供了不一致的安全裕度，因为没有考虑裂纹粗糙度。一致性安全的设计方程需要考虑表面粗糙度作为输入变量。

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引用次数: 0

Coupled effects of brittleness and fracture geometry on the damage evolution and mechanical degradation of sandstone 脆性和断裂几何对砂岩损伤演化和力学退化的耦合影响

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-02-03 DOI: 10.1016/j.tafmec.2026.105480

Dejun Liu , Hai Pu , Xiaoding Xu , Yunhui Fan , Kangsheng Xue , LuluLiu , Hao Zhang , Qingyu Yi

Understanding the coupled influence of material brittleness and fracture geometry on the mechanical degradation and failure behavior of fractured rock is critical for assessing instability in deep underground engineering. In this study, sandstone specimens with two distinct levels of brittleness were prepared with prefabricated fractures characterized by varying inclination angles and rock-bridge angles. A multiscale experimental framework integrating AE-DIC monitoring was employed to systematically investigate damage evolution and fracture mechanisms. To quantitatively characterize mechanical weakening, strength-degradation and elastic-modulus-degradation indices were proposed. The results show that prefabricated fractures significantly reduce the peak strength of sandstone. Increasing the fracture inclination angle leads to higher peak strength, whereas increasing the rock-bridge angle results in a non-monotonic decrease–increase trend. High-brittleness sandstone exhibits larger fluctuations in strength and stiffness under geometric disturbance, indicating stronger sensitivity to fracture-induced heterogeneity. AE-DIC results demonstrate that fracture inclination primarily controls the orientation and intensity of strain localization, while the rock-bridge angle governs the complexity of crack coalescence. High-brittleness specimens develop more concentrated and rapidly evolving strain localization bands, ultimately leading to abrupt mixed tensile–shear failure. Higher brittleness accelerates damage accumulation and promotes shear-dominated microcrack activity, particularly under high fracture inclination and large rock-bridge angles. In contrast, low-brittleness sandstone is characterized by a higher proportion of tensile microcracks and smoother b-value evolution, reflecting more progressive damage development. The degradation indices further reveal that strength deterioration is more pronounced in high-brittleness sandstone, whereas elastic modulus degradation shows greater sensitivity to brittleness reduction in low-brittleness sandstone. Overall, the findings highlight a coupled degradation mechanism in which fracture geometry controls the spatial evolution of damage, while material brittleness governs the rate and severity of mechanical degradation.

了解材料脆性和断裂几何形态对裂隙岩体力学退化和破坏行为的耦合影响，对于评估深部地下工程的失稳至关重要。在本研究中，采用不同倾角和岩桥角度的预制裂缝制备两种不同脆性水平的砂岩试样。采用集成AE-DIC监测的多尺度实验框架，系统研究了损伤演化和断裂机制。为了定量表征机械弱化，提出了强度退化指标和弹性模量退化指标。结果表明：预制裂缝显著降低了砂岩的峰值强度；裂隙倾角越大，峰值强度越高，岩桥倾角越大，峰值强度呈非单调的减小-增大趋势。高脆性砂岩在几何扰动下强度和刚度波动较大，表明其对裂缝非均质性的敏感性较强。AE-DIC结果表明，裂缝倾角主要控制应变局部化的方向和强度，而岩桥角控制裂纹合并的复杂性。高脆性试样的应变局部化带更为集中且演化迅速，最终导致突然性的拉剪混合破坏。较高的脆性加速了损伤积累，促进了剪切主导的微裂纹活动，特别是在高断裂倾角和大岩桥角度下。低脆性砂岩的拉伸微裂纹比例更高，b值演化更平滑，损伤发育更渐进。强度退化在高脆性砂岩中更为明显，而弹性模量退化对低脆性砂岩的脆性降低更为敏感。总的来说，研究结果强调了一种耦合退化机制，其中断裂几何形状控制着损伤的空间演变，而材料脆性控制着机械退化的速度和严重程度。

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引用次数: 0

From stiffness degradation to fatigue life prediction: A nonlinear dynamic signature-based framework for asphalt mixtures 从刚度退化到疲劳寿命预测：基于非线性动态特征的沥青混合料框架

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-02-05 DOI: 10.1016/j.tafmec.2026.105495

Weimin Song

Fatigue cracking in asphalt pavements stems from the complex, nonlinear accumulation of damage, a process further complicated by the use of reclaimed asphalt pavement (RAP) and fiber reinforcements. Traditional fatigue characterization, focusing on macroscopic endpoints, failing to capture the intrinsic dynamic patterns of damage evolution. This study proposes a paradigm shift by conceptualizing fatigue damage accumulation as a nonlinear dynamical system. From stiffness degradation time series, this investigation developed a novel framework that extracts dynamic signatures, including approximate entropy (ApEn), the maximum Lyapunov exponent (λ), and damage rate fluctuation (DRF). These signatures quantitatively describe the complexity, predictability, and stability of the damage process itself. Applying this framework to four types of asphalt mixtures with different contents of RAP and glass fiber tested under direct tension reveals that: 1) incorporating 25% RAP enhances fatigue life by 130% and increases damage complexity (ApEn); 2) an optimal 0.1% glass fiber content maximizes fatigue life (a 214% increase over H-25R) by significantly stabilizing the damage process (lowest DRF); 3) fatigue life correlates strongly with these dynamic signatures. Crucially, a multilinear regression model integrating ApEn and DRF provides accurate fatigue life prediction, resolving the paradoxical roles of damage complexity (beneficial) and instability (detrimental). The framework moves beyond correlation by offering a quantitative, systems-based language to describe damage evolution, thereby providing a critical link between macroscopic performance and the underlying dynamical behavior of the material, and guiding future micromechanical investigations.

沥青路面的疲劳开裂源于复杂的、非线性的损伤积累，而再生沥青路面（RAP）和纤维增强材料的使用使这一过程进一步复杂化。传统的疲劳表征，侧重于宏观端点，未能捕捉损伤演化的内在动态模式。本研究提出了一种范式转换，将疲劳损伤积累概念化为一个非线性动力系统。从刚度退化时间序列中，本研究开发了一个新的框架，可以提取动态特征，包括近似熵（ApEn）、最大Lyapunov指数（λ）和损伤率波动（DRF）。这些特征定量地描述了破坏过程本身的复杂性、可预测性和稳定性。将该框架应用于四种不同RAP和玻璃纤维含量的沥青混合料的直接拉伸试验，结果表明：1)加入25% RAP的沥青混合料的疲劳寿命提高了130%，损伤复杂性（ApEn）增加；2) 0.1%的最佳玻璃纤维含量通过显著稳定损伤过程（最低DRF）使疲劳寿命最大化（比H-25R增加214%）；疲劳寿命与这些动态特征密切相关。最重要的是，集成了ApEn和DRF的多元线性回归模型提供了准确的疲劳寿命预测，解决了损伤复杂性（有益）和不稳定性（有害）的矛盾作用。该框架通过提供一种定量的、基于系统的语言来描述损伤演变，从而超越了相关性，从而提供了材料宏观性能和潜在动态行为之间的关键联系，并指导未来的微观力学研究。

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引用次数: 0

Study on the mixed mode I/III fracture behavior of autoclaved aerated concrete 加气混凝土I/III混合模式断裂行为研究

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-01-20 DOI: 10.1016/j.tafmec.2026.105476

M. Ghadim-Ghobadi , S. Pirmohammad , M. Bakhshizadeh

This study examined fracture behavior of Autoclaved Aerated Concrete (AAC) using a newly developed Modified Edge Notched Disc Bend (MENDB) specimen under five distinct loading conditions, including pure mode I, pure mode III, and three mixed-mode I/III states. The traditional ENDB geometry was prone to premature failure in porous materials due to excessive stress concentration at the supports. To overcome this limitation, the MENDB configuration incorporated truncated supports that prevented crushing near contact regions and allowed accurate fracture testing across a wide range of crack orientations. A finite element (FE) parametric study was conducted to quantify the influence of support span ratio (S/R = 0.7–0.9), crack length ratio (a/B = 0.4–0.6), and crack angle (α = 0°–75.5°) on the geometry factors (Y_I, Y_III) and normalized T-stress. The FE results indicated that increasing α progressively shifted the loading condition from pure mode I to pure mode III; meanwhile, larger S/R values enhanced Y_I at low α but reduced it at higher angles, while Y_III consistently increased with S/R. In contrast, increasing a/B raised Y_I at small α but decreased it for dominant mode III conditions. Furthermore, experiments showed that the fracture resitance (K_f) decreased with increasing mode III contribution, with pure mode III K_f being approximately 61% lower than pure mode I one.

本研究使用新开发的改良边缘缺口盘弯曲（MENDB）试件，在五种不同的加载条件下，包括纯I模式、纯III模式和三种I/III混合模式，测试了加气混凝土（AAC）的断裂行为。传统的ENDB几何结构在多孔材料中容易过早失效，因为支架处应力过于集中。为了克服这一限制，MENDB配置了截断支撑，防止了接触区域附近的破碎，并允许在大范围的裂缝方向上进行精确的断裂测试。通过有限元参数化研究，量化了支撑跨度比（S/R = 0.7 ~ 0.9）、裂缝长度比（A /B = 0.4 ~ 0.6）和裂缝角度（α = 0°~ 75.5°）对几何因子（YI、YIII）和归一化t应力的影响。结果表明，α的增加使加载状态由纯ⅰ型逐渐转变为纯ⅲ型；同时，较大的S/R值在低α时增加了YI，但在高角度时降低了YI，而YIII随着S/R的增加而增加。相比之下，在小α条件下，增加a/B会提高YI，但在优势模式III条件下会降低YI。此外，实验表明，断裂阻力（Kf）随着III型贡献的增加而降低，纯III型Kf比纯I型Kf低约61%。

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引用次数: 0

Study on crack propagation law and plastic failure mechanism around extraction borehole 抽采钻孔周围裂纹扩展规律及塑性破坏机理研究

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-01-15 DOI: 10.1016/j.tafmec.2026.105462

Yongzan Wen , Wei Yang , Mengfei Song , Tianfu Wang , Yihan Wang , Minghua Lin

The evolution of cracks and the formation of plastic failure zones around boreholes constitute crucial seepage channels for efficient gas extraction. To investigate the crack propagation behavior and plastic failure mechanisms surrounding boreholes, cubic coal specimens with various spatial configurations were tested. The surface strain field evolution during uniaxial compression tests was monitored using the Digital Image Correlation (DIC) technique. Combined with elastoplastic mechanics theory, a computational model for the plastic zone boundary around boreholes was established to explore the influencing factors of the plastic region. The results show that circular boreholes, as initial defects, significantly deteriorate the mechanical properties of coal specimens. Both uniaxial compressive strength and elastic modulus decrease markedly with an increasing number of boreholes. The evolution of “butterfly-shaped” strain concentration zones around boreholes dominates crack initiation and propagation, while the superposition of strain fields among multiple boreholes is the primary cause of accelerated degradation of the specimens. Furthermore, the cooperative interaction among multiple boreholes expands the influence range of the plastic zones. Theoretical analysis indicates that under deviatoric stress conditions, a “butterfly-shaped” plastic zone forms around the borehole, with the butterfly lobes oriented at approximately θ ≈ 45°, representing preferential zones for shear crack development. The extent of the plastic zone is positively correlated with the borehole radius and lateral pressure coefficient, but negatively correlated with coal cohesion and internal friction angle. The butterfly-shaped plastic zone around the borehole defines the “effective permeability enhancement zone” for gas extraction. Utilizing the superposition effect of plastic zones induced by multi-borehole disturbance can extend the permeability enhancement range and enlarge the fracture connectivity region, thereby providing a theoretical basis for optimizing the borehole layout in gas drainage operations.

钻孔周围裂隙的演化和塑性破坏带的形成是有效抽采瓦斯的重要渗流通道。为了研究钻孔周围裂纹扩展行为和塑性破坏机制，对不同空间构型的立方煤试件进行了试验。采用数字图像相关（DIC）技术对单轴压缩试验过程中的表面应变场演化进行了监测。结合弹塑性力学理论，建立了钻孔周边塑性区边界的计算模型，探讨了塑性区的影响因素。结果表明：圆孔作为初始缺陷，会显著破坏煤样的力学性能；随着钻孔数的增加，单轴抗压强度和弹性模量均显著降低。孔周围“蝴蝶形”应变集中区的演化主导了裂纹的萌生和扩展，而多个孔间应变场的叠加是试件加速退化的主要原因。此外，多钻孔间的协同作用扩大了塑性区的影响范围。理论分析表明，在偏应力条件下，井眼周围形成“蝴蝶形”塑性区，其蝶叶方向约为θ≈45°，是剪切裂缝发育的优先区域。塑性区范围与钻孔半径、侧压系数呈正相关，与煤体黏聚力、内摩擦角呈负相关。井眼周围的蝴蝶状塑性区定义了天然气开采的“有效增渗区”。利用多井眼扰动引起的塑性区叠加效应，可以扩大渗透率增强范围，扩大裂缝连通性区域，从而为瓦斯抽采作业中优化井眼布置提供理论依据。

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引用次数: 0

Influence of stress dwell location on the creep–fatigue behavior of notched nickel-based single-crystal superalloy specimens at 900 °C 应力驻留位置对缺口镍基单晶高温合金900℃蠕变疲劳行为的影响

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-01-20 DOI: 10.1016/j.tafmec.2026.105469

Jundong Wang , Xiaolei Gu , Xiangqian Xu , Zhixun Wen , Zhufeng Yue

Nickel-based single-crystal superalloys are widely employed in critical hot-section components of aero-engines and industrial gas turbines. In this study, high-temperature creep-fatigue interaction tests were conducted on notched specimens of a nickel-based single-crystal superalloy under different stress dwell locations, including baseline cycling without dwell (baseline), dwell at maximum stress (“max dwell”), and dwell at minimum stress (“min dwell”). The results demonstrate that the stress dwell location exerts a pronounced influence on the fatigue life and failure modes of notched specimens. Specifically, under baseline cycling and min dwell conditions, failure is dominated by the initiation and propagation of surface-initiated fatigue cracks. In contrast, under max dwell conditions, the fracture surfaces exhibit a mixed morphology characterized by the coexistence of quasi-cleavage facets and dimpled microvoid coalescence. A damage-coupled viscoplastic constitutive model was employed to simulate the cyclic response of notched specimens under different dwell conditions by finite element analysis, and the predictions indicate that the model can reasonably reproduce the crack initiation and evolution behavior over a range of stress dwell locations. On this basis, the classical Basquin fatigue life model was modified by incorporating stress triaxiality and damage evolution metrics, thereby establishing a life prediction methodology applicable to high-temperature notched creep-fatigue interaction, which captures the observed trends in life degradation with satisfactory accuracy.

镍基单晶高温合金广泛应用于航空发动机和工业燃气轮机的关键热截面部件。在本研究中，对镍基单晶高温合金的缺口试样进行了不同应力驻留位置下的高温蠕变-疲劳相互作用试验，包括无驻留基线循环（基线）、最大驻留应力（“最大驻留”）和最小驻留应力（“最小驻留”）。结果表明，应力驻留位置对缺口试样的疲劳寿命和破坏模式有显著影响。具体来说，在基线循环和最小停留条件下，失效主要是由表面疲劳裂纹的萌生和扩展引起的。相反，在最大停留条件下，断口表面表现为准解理面和微孔聚结共存的混合形貌。采用损伤耦合粘塑性本构模型对缺口试件在不同静置条件下的循环响应进行了有限元模拟，结果表明，该模型能够较好地再现缺口试件在不同应力静置位置下的裂纹萌生与演化行为。在此基础上，通过引入应力三轴性和损伤演化指标对经典Basquin疲劳寿命模型进行修正，建立了一种适用于高温缺口蠕变-疲劳相互作用的寿命预测方法，该方法以令人满意的精度捕获了观察到的寿命退化趋势。

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引用次数: 0

Mechanical behavior and fracture evolution of ice-filled fissured red sandstone under coupled temperature-inclination effects 温度-倾斜度耦合作用下充冰裂隙红砂岩力学行为及裂缝演化

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-02-10 DOI: 10.1016/j.tafmec.2026.105507

Zhen Wang , Zilong Zhou , Dong Wang , Jun Hou , Jiaming Wang

Ice-filled fissures are widely developed in rock masses in cold regions, and their dynamic mechanical behavior directly affects the stability and safety of engineering rock structures. This paper systematically investigates the mechanical response and fracture evolution characteristics of red sandstone with ice-filled fissures under dynamic impact loading using a split Hopkinson pressure bar (SHPB) experimental system combined with high-speed photography and digital image correlation (DIC) technology, while controlling the inclination angle of ice-filled fissures, temperature, and impact velocity. Results show that the dynamic peak strength and energy dissipation vary non-monotonically with fissure inclination angle, reaching their lowest values at 60° (approximately 47.15% lower than that of 0° inclination at −30 °C). Temperature influences the mechanical behavior differently across inclination angles: specimens with 0° and 90° fissures exhibit the highest strength at −30 °C (123 MPa and 117 MPa, respectively), while those with 30° and 60° fissures reach peak strength at −40 °C (85 MPa and 78 MPa, respectively). With increasing impact velocity, the peak stress of all specimen types rises significantly. Quantitative DIC strain field analysis indicates that specimens with 0° and 90° fissures primarily undergo tensile failure, whereas those with 30° and 60° fissures exhibit tensile–shear composite failure, with the most pronounced strain localization and unstable crack propagation observed at 60° inclination. Finally, the study reveals the strengthening–damage competition mechanism in specimens under dynamic loading from the perspectives of stress wave propagation and micro-damage evolution, providing experimental and theoretical support for safety control in rock engineering in cold regions.

冰雪裂隙在寒区岩体中广泛发育，其动力力学行为直接影响工程岩体结构的稳定与安全。采用分离式霍普金森压杆（SHPB）实验系统，结合高速摄影和数字图像相关（DIC）技术，在控制冰缝倾角、温度和冲击速度的条件下，系统研究了含冰缝红砂岩在动态冲击载荷作用下的力学响应和裂缝演化特征。结果表明：动态峰值强度和能量耗散随裂缝倾角呈非单调变化，在60°时达到最小值（在- 30°C时比0°倾角时低约47.15%）；温度对不同倾角下试件力学行为的影响不同：0°和90°裂缝试件在- 30℃时强度最高（分别为123 MPa和117 MPa），而30°和60°裂缝试件在- 40℃时强度最高（分别为85 MPa和78 MPa）。随着冲击速度的增加，各试样的峰值应力均显著升高。定量DIC应变场分析表明，裂隙为0°和90°的试样以拉伸破坏为主，而裂隙为30°和60°的试样则表现为拉剪复合破坏，且在倾角为60°时应变局部化最为明显，裂纹扩展不稳定。最后，从应力波传播和微损伤演化的角度揭示了动荷载作用下试件的强化-损伤竞争机制，为寒区岩石工程的安全控制提供了实验和理论支持。

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引用次数: 0

Mixed-mode(I/II) fracture behaviour and criterion-based analysis of banana fiber reinforced epoxy composites using asymmetric SCB specimens 香蕉纤维增强环氧复合材料的I/II混合模式断裂行为及基于准则的非对称SCB试样分析

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-04-01 Epub Date: 2026-01-02 DOI: 10.1016/j.tafmec.2025.105433

L.C. Shashidhar , Saravanabavan , Rajeev Kumar Gupta , S.C. Ramesh Kumar , R. Vara Prasad Kaviti , M.A. Umarfarooq , Vinayak S. Uppin , B.H. Maruthi Prashanth

This work investigates the mixed-mode (I/II) fracture behaviour of banana fiber-reinforced epoxy composite using asymmetric semi-circular bend (ASCB) specimens. Laminates were fabricated via hand layup-assisted vacuum bag moulding, with banana fibers integrated into an epoxy matrix. Three-point bending tests were conducted on ASCB specimens (radius 60 mm, thickness 6 mm, and notch length 30 mm) under varying asymmetric support spans (40–40 mm to 40–20 mm) to transition from pure mode I to mixed-mode I/II loading. Results showed a non-monotonic mode I fracture toughness (K_I) trend (1.70 MPa.m^1/2 decreasing to 1.54 MPa.m^1/2, then increasing to 1.92 MPa.m^1/2) and rising mode II fracture toughness (K_II) (0.30 to 0.87 MPa.m^1/2) with increasing mode II contribution, attributed to fiber-matrix interactions.

Experimental results were compared with analytical predictions based on the Power Law, maximum tangential stress (MTS), generalised maximum tangential stress (GMTS), and maximum energy release rate (Gmax) criteria. The Power Law criterion underestimated fracture resistance failing to capture constraint effects and fiber-related toughening. Incorporation of T-stress in the MTS and GMTS models improved predictions, though both overestimated crack initiation angles. Among the compared criteria, Gmax provided the closest correlation with crack initiation angles (0° to −17.26°), highlighting its suitability for natural fiber composites. Overall, the findings reveal a strong dependence of mixed-mode fracture behaviour on fiber-matrix interaction mechanisms, confirming the suitability of energy-based criteria for accurately modelling the fracture response of anisotropic natural fiber composites.

本文采用非对称半圆弯曲（ASCB）试样研究了香蕉纤维增强环氧复合材料的混合模式（I/II）断裂行为。层压板是通过手工分层辅助真空袋成型制造的，香蕉纤维集成到环氧树脂基体中。对ASCB试件（半径60 mm，厚度6 mm，缺口长度30 mm）在不同的非对称支承跨度（40-40 mm ~ 40-20 mm）下进行了由纯I型加载过渡到混合I/II型加载的三点弯曲试验。结果表明，断裂韧性呈非单调I型（1.70 MPa）趋势。m1/2减小到1.54 MPa。m1/2，然后增加到1.92 MPa。m1/2)， II型断裂韧性（KII）上升（0.30 ~ 0.87 MPa）。m1/2)，模式II贡献增加，归因于纤维-基质相互作用。实验结果与基于幂律、最大切向应力（MTS）、广义最大切向应力（GMTS）和最大能量释放率（Gmax）准则的分析预测结果进行了比较。幂律准则低估了断裂抗力，未能捕捉到约束效应和纤维相关的增韧。在MTS和GMTS模型中加入t应力改进了预测，尽管两者都高估了裂纹起裂角。其中，Gmax与裂纹起裂角（0°~ - 17.26°）的相关性最密切，突出了其对天然纤维复合材料的适用性。总的来说，研究结果揭示了混合模式断裂行为对纤维-基质相互作用机制的强烈依赖，证实了基于能量的标准准确模拟各向异性天然纤维复合材料断裂响应的适用性。

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引用次数: 0