Theoretical and Applied Fracture Mechanics最新文献_第5页

Phase field modeling of combustion-gas induced pressurized fracture within viscoelastic solid propellant grain 黏弹性固体推进剂颗粒内燃气致加压断裂的相场模拟

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-15 DOI: 10.1016/j.tafmec.2026.105464

Jiatong Tan , Qun Li , Zhihong Wang , Xianghua Chen , Yingxuan Dong

Solid propellant grain is a vital part of solid rocket motor (SRM), which provides the combustion product gas and serves as the main energy source. However, the defects like voids and cracks could be formed within grain during the manufacture, transportation, and storage. After ignition, combustion gas might penetrate these cracks, causing rapid pressurization and significant pressure buildup within the cavities. Subsequently, the crack evolution not only produces extra burning areas, but also compromises the structural integrity. This work has developed a phase field model of pressurized fracture for the viscoelastic solid propellant crack. Governing equations of physical model together with the discretization were derived firstly. Constitutive equation and phase field model were verified subsequently. Finally, the crack behaviors and failure mechanisms at different pressurization rates and relaxation times have been analyzed. Simulation results revealed that crack propagated along the initial direction with the minimum pressurization rate, and crack tip experienced significant tensile stress. As the pressurization rate increased, crack propagation was initiated and followed by crack branching, while the failure mechanism was tension-controlled. Crack branching occurred earlier with a further increasing of pressurization rate, and crack evolution became dominated by shear failure. Furthermore, decreasing relaxation time advanced the onset of crack propagation and diminished the stress at crack tip. These crack behaviors are consistent with experimental conclusions in the literature, making it possible to implement this model for the engineering analysis.

固体推进剂颗粒是固体火箭发动机的重要组成部分，提供燃烧产物气体，是发动机的主要能量来源。然而，在制造、运输和储存过程中，晶粒内部容易形成空洞和裂纹等缺陷。点火后，燃烧气体可能会穿透这些裂缝，导致腔内快速加压和显著的压力积聚。随后，裂纹的演化不仅会产生额外的燃烧区域，而且会损害结构的完整性。本文建立了粘弹性固体推进剂裂纹受压断裂的相场模型。首先推导了物理模型的控制方程，并进行了离散化处理。随后对本构方程和相场模型进行了验证。最后，分析了不同加压速率和松弛时间下的裂纹行为和破坏机制。模拟结果表明，在最小增压速率下，裂纹沿初始方向扩展，裂纹尖端承受较大的拉应力。随着加压速率的增加，裂纹扩展开始，随后出现裂纹分支，破坏机制为张力控制。随着加压速率的进一步增大，裂纹分支发生的时间提前，裂纹演化以剪切破坏为主。同时，减小弛豫时间有利于裂纹扩展的开始和裂纹尖端应力的减小。这些裂纹行为与文献中的实验结论相吻合，为该模型在工程分析中的应用提供了可能。

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引用次数: 0

Modeling crack behavior with a state-based peridynamics approach: a fatigue damage framework incorporating elasto-plastic deformation fields 基于状态动力学方法的裂纹行为建模：含弹塑性变形场的疲劳损伤框架

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-15 DOI: 10.1016/j.tafmec.2026.105465

D. Bang , A. Ince

Fatigue crack growth in metallic alloys is strongly influenced by elastic–plastic deformation at the crack tip, which is not fully captured by traditional linear elastic fracture mechanics (LEFM) and existing peridynamics (PD) fatigue models. This study introduces a novel peridynamics (PD) elastic-plastic fatigue damage framework that directly computes crack-tip elastic–plastic stress–strain fields and couples them with a Smith–Watson–Topper (SWT) strain-energy-density driving force. Hencky's plasticity equations, the multiaxial Neuber rule, and a stress-redistribution factor are integrated within the ordinary state-based PD formulation to obtain nonlocal elastic–plastic fields under cyclic loading. The SWT parameter is evaluated at the bond level using these fields to determine the number of cycles to bond failure and to drive crack growth. The proposed framework is verified by comparing PD elastic–plastic stress distributions against finite element (FE) solutions for SAE 1070 steel, and it is validated against experimental crack growth data for 6061-T6, A356-T6, and 7075-T6 aluminum alloys. Across all materials, the model correlates well with the crack growth responses and stress field data near the crack tip with good accuracy by demonstrating that incorporating elastic–plastic strain energy within a state-based PD framework provides a physically consistent and predictive tool for fatigue crack growth analysis. The study shows that incorporating elastic–plastic strain energy within a state-based PD framework provides a physically consistent and predictive tool for fatigue crack growth analysis.

金属合金的疲劳裂纹扩展受裂纹尖端的弹塑性变形的强烈影响，传统的线弹性断裂力学（LEFM）和现有的周动力学（PD）疲劳模型不能完全反映这种影响。本研究提出了一种新的周动力学弹塑性疲劳损伤框架，该框架直接计算裂纹尖端弹塑性应力-应变场，并将其与Smith-Watson-Topper （SWT）应变-能量密度驱动力耦合。将Hencky塑性方程、多轴Neuber规则和应力重分布因子整合到普通的基于状态的PD公式中，得到循环加载下的非局部弹塑性场。SWT参数使用这些字段在键合水平上进行评估，以确定键合失效的循环次数并驱动裂纹扩展。通过将PD弹塑性应力分布与SAE 1070钢的有限元解进行比较，并与6061-T6、A356-T6和7075-T6铝合金的裂纹扩展实验数据进行了验证。在所有材料中，该模型都能很好地与裂纹扩展响应和裂纹尖端附近的应力场数据相关联，并具有很高的准确性，证明了在基于状态的PD框架内结合弹塑性应变能，为疲劳裂纹扩展分析提供了物理上一致的预测工具。研究表明，在基于状态的PD框架中结合弹塑性应变能，为疲劳裂纹扩展分析提供了一种物理上一致的预测工具。

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引用次数: 0

Fracture mechanical properties of ultra-high performance concrete under mode I/II mixed fracture: A study on the coupling effect of steel Fiber content and crack-to-depth ratio I/II型混合断裂下超高性能混凝土的断裂力学性能——钢纤维掺量与裂缝深度比耦合效应研究

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-12 DOI: 10.1016/j.tafmec.2026.105451

Zhiqing Zhao, Xiangfei Cheng, Guoqing Li, Xingqing Gu, Chen Wu, Peiwei Gao

Ultra-high performance concrete (UHPC) is a widely used material in long-span structures, and its service performance and failure process are often governed by Mode I/II mixed fracture. To reveal the mixed-mode fracture mechanism of UHPC beams under the coupling effect of steel fiber content (referring to volume fraction V_f) and Crack-to-depth Ratio (CDR), a three-point bending experiment for UHPC specimens with inclined prefabricated cracks was designed in this study by considering the V_f range of 0%–3% and the CDR range of 0.15–0.80. Specifically, the data of load, displacement, and crack propagation path evolution throughout the entire fracture process were obtained via the load-crack mouth opening displacement (P-CMOD) curves by employing the digital image correlation (DIC) technology. The Mode I/II components of the crack initiation toughness and unstable fracture toughness were derived using the single-specimen η-method combined with linear elastic finite element analysis. The results indicate that increasing the steel fiber content can significantly enhance the unstable load, whereas a higher CDR weakens the fiber strengthening efficacy and reduces the unstable load of the material. Both Mode I and Mode II components of the crack initiation toughness reached their threshold values at a CDR of 0.45. As the fiber content and CDR increased further, the unstable fracture gradually transitioned from being Mode I-dominated to Mode II-dominated. DIC analysis shows that when CDR < 0.60, steel fibers primarily retarded crack propagation by inhibiting the equivalent crack opening displacement (COD_eff); when CDR ranged from 0.60 to 0.80, steel fibers achieved energy dissipation at the crack tip by restricting the equivalent crack sliding displacement (CSD_eff). By revealing the coupling mechanism between geometric constraints and fiber bridging, this study quantified the dynamic correlations among displacement, load, and crack propagation under Mode I/II mixed fracture, providing important theoretical support for the crack resistance design and performance evaluation of UHPC structures.

超高性能混凝土（UHPC）是大跨度结构中广泛应用的材料，其使用性能和破坏过程往往受I/II型混合断裂的支配。为了揭示钢纤维含量（指体积分数Vf）和裂纹深度比（CDR）耦合作用下UHPC梁的混合模式断裂机理，本研究设计了具有倾斜预制裂缝的UHPC试件三点弯曲试验，Vf范围为0% ~ 3%，CDR范围为0.15 ~ 0.80。具体而言，采用数字图像相关（DIC）技术，通过载荷-裂纹开口位移（P-CMOD）曲线获得整个断裂过程中的载荷、位移和裂纹扩展路径演化数据。采用单试样η法结合线弹性有限元分析，推导了裂纹起裂韧性和不稳定断裂韧性的I/II型分量。结果表明：增加钢纤维含量可显著增强材料的不稳定载荷，而较高的CDR会减弱纤维增强效果，降低材料的不稳定载荷。裂纹起裂韧性的模式I和模式II分量均在CDR为0.45时达到阈值。随着纤维含量和CDR的进一步增加，不稳定断裂逐渐由i型为主过渡到ii型为主。DIC分析表明，当CDR <； 0.60时，钢纤维主要通过抑制等效裂纹张开位移（CODeff）来延缓裂纹扩展；当CDR在0.60 ~ 0.80范围内时，钢纤维通过限制等效裂纹滑动位移（CSDeff）来实现裂纹尖端的能量耗散。通过揭示几何约束与纤维桥接之间的耦合机制，量化了I/II型混合断裂下位移、荷载与裂纹扩展之间的动态关联，为UHPC结构的抗裂设计和性能评价提供了重要的理论支持。

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引用次数: 0

Determination and evolution of mode-I dynamic fracture toughness in granite under coupled water pressure and static stress 水压与静应力耦合作用下花岗岩i型动态断裂韧性的测定与演化

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-12 DOI: 10.1016/j.tafmec.2026.105459

Jiefang Jin, Xiaowang Peng, Daoxue Yang, Youfeng Xiao, Huiying Xiong, Shuang Hao, Lixing Fang, Wei Yuan

Disasters such as water inrush induced by blasting and excavation frequently occur in deep rock engineering. These are closely associated with microcrack formation and expansion in rock. Their prevention requires a thorough understanding of the dynamic fracture behavior of rocks under coupled static stress and water pressure conditions. To address this issue, a testing method for determining the mode-I dynamic fracture toughness of rocks under such coupled conditions was developed using a self-designed rock dynamics system capable of applying static stress and water pressure. Dynamic fracture experiments were conducted on granite specimens to investigate the effects of dynamic loading rate and water pressure on mode-I dynamic fracture toughness. An evolution model was then established. The evolution mechanism was further elucidated through combined macroscopic and microscopic fracture analyses. Results indicate that, under a constant water pressure, the mode-I dynamic fracture toughness follows a power-function increase with increasing loading rate, although the enhancement becomes less pronounced at high loading rates. Under a fixed loading rate, the toughness rises linearly with water pressure. Macroscopically, higher water pressure and loading rate reduce both fracture expansion contour roughness and fractal dimension. Microscopically, the fracture mechanism transitions from intergranular to transgranular failure. These findings provide theoretical guidance for preventing water inrush disasters induced by blasting and excavation.

在深部岩体工程中，爆破开挖引起突水等灾害是常见的灾害。它们与岩石微裂纹的形成和扩展密切相关。预防这些问题需要彻底了解岩石在静应力和水压耦合条件下的动态破裂行为。为了解决这一问题，利用自行设计的能够施加静应力和水压的岩石动力学系统，开发了在这种耦合条件下确定岩石i型动态断裂韧性的测试方法。通过对花岗岩试件进行动态断裂试验，研究动加载速率和水压对花岗岩ⅰ型动态断裂韧性的影响。然后建立了进化模型。通过宏观与微观相结合的断裂分析进一步阐明了其演化机制。结果表明，在恒定水压条件下，随着加载速率的增加，ⅰ型动态断裂韧性呈幂函数增长，但在高加载速率下，这种增强不明显；在一定加载速率下，韧性随水压线性上升。宏观上，较高的水压和加载速率降低了裂缝扩展轮廓粗糙度和分形维数。微观上，断裂机制由晶间断裂向穿晶断裂转变。研究结果对防治爆破开挖突水灾害具有一定的理论指导意义。

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引用次数: 0

Study on the mechanical properties and fracture behavior of coal gangue aggregate concrete modified by physical-chemical composite 物化复合改性煤矸石骨料混凝土力学性能及断裂行为研究

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-09 DOI: 10.1016/j.tafmec.2026.105452

Xiangdong Zhang , Yao Dong , Wenliang Li , Yu Zhang , Lijuan Su , Guanjun Cai , Qiong Wu

The accumulation of coal gangue (CG) as an industrial solid waste has become increasingly severe, and its resource utilization is of great significance for promoting low-carbon development in the construction industry. To enhance the utilization of coal gangue (CG), this study introduces for the first time a composite modification technique combining “physical coating and chemical immersion” for coal gangue aggregate (CGA), which was used to fabricate coal gangue aggregate concrete (CGAC). Through multi-scale experiments and characterization techniques, the synergistic modification mechanisms of the composite method on the properties of coal gangue aggregate (CGA) and concrete are systematically investigated, with a focus on analyzing the mechanical characteristics and fracture behavior of CGAC. Experimental results indicate that the composite modification significantly improves the fundamental physical and mechanical properties of CGA, optimizing its morphological characteristics, including sphericity, elongation, flatness, and angularity. The mechanical properties of the modified CGAC are notably enhanced, with 28d compressive strength, splitting tensile strength, and flexural strength increasing by 39.7%, 45.1%, and 42.5%, respectively, compared to the control group. Based on three-point bending fracture tests combined with digital image correlation (DIC) technology, it is found that the cracking load, ultimate load, fracture toughness, and fracture energy of the composite-modified CGAC are significantly improved, demonstrating superior crack resistance. Microscopic tests reveal that sodium silicate and silane coupling agents chemically strengthen the interfacial bonding between the cement matrix and CGA, forming a dense interfacial transition zone (ITZ), which further enhances the overall performance of CGAC. By leveraging the synergistic mechanism of “physical coating to address structural defects + chemical immersion to enhance interfacial chemistry,” this approach achieves dual reinforcement of the interfacial transition zone (ITZ). Compared to single modification methods, it leads to significant improvements in key properties such as aggregate mechanical strength and concrete fracture toughness. This study provides a solid theoretical foundation and practical technical support for the research on the fracture mechanical properties of CGAC.

煤矸石作为一种工业固体废弃物，其积累日益严重，其资源化利用对于推动建筑行业低碳发展具有重要意义。为提高煤矸石的利用率，首次提出了煤矸石骨料“物理包覆-化学浸渍”复合改性技术，用于制备煤矸石骨料混凝土（CGAC）。通过多尺度实验和表征技术，系统研究了复合方法对煤矸石骨料（CGA）和混凝土性能的协同改性机理，重点分析了CGAC的力学特性和断裂行为。实验结果表明，复合改性显著改善了CGA的基本物理力学性能，优化了其形貌特征，包括球度、伸长率、平整度和角度。改性后的CGAC力学性能明显增强，28d抗压强度、劈裂抗拉强度和抗弯强度分别比对照组提高39.7%、45.1%和42.5%。结合数字图像相关（DIC）技术进行三点弯曲断裂试验，发现复合改性CGAC的开裂载荷、极限载荷、断裂韧性和断裂能均有显著提高，具有较好的抗裂性能。微观试验表明，水玻璃和硅烷偶联剂化学强化了水泥基体与CGAC之间的界面结合，形成致密的界面过渡区（ITZ），进一步提高了CGAC的整体性能。通过利用“物理涂层解决结构缺陷+化学浸泡增强界面化学”的协同机制，该方法实现了界面过渡区（ITZ）的双重强化。与单一改性方法相比，它能显著改善骨料机械强度和混凝土断裂韧性等关键性能。本研究为CGAC断裂力学性能的研究提供了坚实的理论基础和实践技术支持。

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引用次数: 0

Effect of testing temperatures on the toughness properties of Q355 steel welded at ambient and low temperatures 试验温度对Q355钢常温和低温焊接韧性性能的影响

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-09 DOI: 10.1016/j.tafmec.2026.105457

Tong Sun , Jianlei Zou , Yuanqing Wang , Yongjiu Shi

This study systematically investigates the coupled influence of welding environmental temperature and testing temperature on the fracture behavior and ductile-to-brittle transition characteristics of Q355 steel welded joints. Charpy impact and fracture toughness tests were performed on the weld metal (WM) and heat-affected zone (HAZ) over a testing temperature range from 23 °C to −100 °C under two welding conditions: room-temperature welding (23 °C) and low-temperature welding (−10 °C). The transition behavior was evaluated using the Master Curve methodology and Boltzmann fitting from both impact- and fracture-mechanics-based perspectives. The results demonstrate that low-temperature welding significantly enhances low-temperature fracture toughness and reduces data scatter in both WM and HAZ. Both the reference temperature T₀ and the ductile-to-brittle transition temperature T_t are shifted to lower values under low-temperature welding, reflecting reduced embrittlement sensitivity. While the WM consistently exhibits higher fracture toughness than the HAZ, the HAZ remains more sensitive to low temperatures. Moreover, discrepancies between impact-based and fracture-mechanics-based transition temperatures are minor in the WM but pronounced in the HAZ, highlighting the different sensitivities of the two methods to fracture mechanisms. These findings provide mechanistic insight into low-temperature embrittlement of welded joints and offer practical guidance for optimizing welding procedures and fracture safety assessment of Q355 steel structures operating in cold environments.

系统研究了焊接环境温度和试验温度对Q355钢焊接接头断裂行为和韧脆转变特性的耦合影响。在室温焊接（23°C）和低温焊接（- 10°C）两种焊接条件下，在23°C至- 100°C的测试温度范围内，对焊缝金属（WM）和热影响区（HAZ）进行了Charpy冲击和断裂韧性测试。从冲击和断裂力学的角度，利用主曲线方法和玻尔兹曼拟合来评估过渡行为。结果表明，低温焊接显著提高了材料的低温断裂韧性，降低了WM和HAZ中的数据散射。低温焊接时，参考温度T0和韧脆转变温度Tt均降低，反映出脆性敏感性降低。虽然WM始终表现出比HAZ更高的断裂韧性，但HAZ对低温更加敏感。此外，基于冲击和基于断裂机制的转变温度之间的差异在WM中很小，但在HAZ中却很明显，这突出了两种方法对断裂机制的不同敏感性。这些研究结果为研究焊接接头低温脆的机理提供了理论依据，为Q355钢结构在低温环境下的焊接工艺优化和断裂安全评价提供了实践指导。

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引用次数: 0

Physics-informed learning of fatigue crack growth in corroded steel: A Paris-law extension with corrosion degree and stress ratio optimized by Bayesian tuning 腐蚀钢疲劳裂纹扩展的物理信息学习：一个由贝叶斯调谐优化的腐蚀程度和应力比的巴黎定律扩展

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-09 DOI: 10.1016/j.tafmec.2026.105456

Yiwei Wang , Yong Zeng , Jinrui Tang , Hongmei Tan , Tuoying Sun , Chao Wu

Fatigue degradation of corroded steels presents complex interactions between mechanical loading, stress ratio, and corrosion-induced defects, which are difficult to capture using empirical models. A Physics-Informed Neural Network (PINN) framework is developed, that embeds the residual form of Paris law into its loss function, enabling the prediction of fatigue crack growth rates in chloride-corroded Q690 steel. Then, A dimensionally consistent extension of the Paris equation is proposed by incorporating the corrosion degree (P) and stress ratio (R), calibrated through single-edge notched tension (SENT) tests. Furthermore, Bayesian Optimization (BO) is employed to automatically tune key hyperparameters of the PINN, improving convergence stability and predictive accuracy. The proposed model achieves superior agreement with experimental data compared with conventional Paris-type formulations and data-driven baselines, demonstrating the feasibility of combining physics-informed learning with corrosion-aware modeling for reliable fatigue life prediction in structural steels.

腐蚀钢的疲劳退化表现出机械载荷、应力比和腐蚀缺陷之间复杂的相互作用，这很难用经验模型来捕捉。提出了一种基于物理信息的神经网络（PINN）框架，该框架将巴黎定律的残余形式嵌入到其损失函数中，从而能够预测氯化物腐蚀Q690钢的疲劳裂纹扩展速率。然后，结合腐蚀程度(P)和应力比(R)，通过单刃缺口拉伸（SENT）试验校准，提出了巴黎方程的维度一致扩展。此外，采用贝叶斯优化（BO）方法自动调整PINN的关键超参数，提高了收敛稳定性和预测精度。与传统的paris型公式和数据驱动基线相比，所提出的模型与实验数据的一致性更好，证明了将物理知识学习与腐蚀感知建模相结合的可行性，可以可靠地预测结构钢的疲劳寿命。

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引用次数: 0

An elasto-plastic phase field framework for hydrogen-assisted failure with a stress-state-dependent critical fracture energy 具有应力状态依赖临界断裂能的氢辅助破坏弹塑性相场框架

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-09 DOI: 10.1016/j.tafmec.2026.105455

Sarnath Thoudam , Daniel C.F. Ferreira , Claudio Ruggieri , Diego F.B. Sarzosa

A coupled mechanical-diffusion-damage model has been developed to simulate hydrogen-assisted failure. The adopted framework is codified in Abaqus/Standard routines, including a UMAT for updating the mechanical constitutive response and a UEL for solving the hydrogen diffusion and phase-field damage evolution. A new feature is the implementation of a critical fracture energy

G_{c}

, which depends on the Lode angle

(θ)

and the stress triaxility

(η)

. Likewise, an energy-based damage threshold parameter is also obtained in terms of the stress invariants. A numerical study is conducted to demonstrate the capabilities of the proposed model. The model is subsequently calibrated and verified using notched specimens of high-strength AISI 4135 steel. After calibration using specimens having a notch radius of

R

=0.1 mm, the simulated fracture strengths match the experimental results. For specimens with

R

=0.8 mm, which exhibit a different constraint level than the hydrogen-charged specimens used for calibration, the model yields conservative predictions of fracture strength, with an average deviation of 26%. The FORTRAN subroutines are freely available for teaching and research from the following link https://sites.usp.br/namef/vumat-umat/.

建立了一个力学-扩散-损伤耦合模型来模拟氢辅助破坏。采用Abaqus/Standard程序编制框架，包括用于更新力学本构响应的UMAT和用于求解氢扩散和相场损伤演化的UEL。一个新的特征是临界断裂能Gc的实现，它取决于Lode角（θ）和应力三轴性（η）。同样，根据应力不变量，得到了基于能量的损伤阈值参数。通过数值研究验证了该模型的有效性。该模型随后使用高强度AISI 4135钢的缺口试样进行校准和验证。采用缺口半径R=0.1 mm的试样进行校正后，模拟的断裂强度与实验结果吻合。对于R=0.8 mm的试样，其约束水平与用于校准的带电试样不同，该模型对断裂强度的预测较为保守，平均偏差为26%。FORTRAN子程序可从以下链接https://sites.usp.br/namef/vumat-umat/免费用于教学和研究。

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引用次数: 0

Investigation of mixed mode I-II damage and fracture properties of concrete subjected to sulfate corrosion and freeze-thaw cycles 硫酸盐腐蚀和冻融循环作用下混凝土I-II混合模式损伤与断裂特性研究

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-08 DOI: 10.1016/j.tafmec.2026.105453

Bing Fan , Li Song , Bowen Guo , Guojie Luo , Zhimeng Gao , Weiping Wu , Hongliang Fang , Tong Li , Zhong Liu

This study investigates the influence of sulfate corrosion and freeze-thaw cycles on the mixed mode I-II damage and fracture behavior of concrete. First, the mass loss and dynamic elastic modulus of concrete beams after different freeze-thaw cycles were measured, and the internal pore structure and mineral composition were analyzed using NMR and XRD. Subsequently, fracture tests under quasi-static loading were conducted on concrete beams in combination with the acoustic emission technique. The evolution patterns of the AE energy, AF-RA parameters, and b-value under sulfate corrosion and freeze-thaw cycles were systematically analyzed. Finally, the finite element method was employed to explore the mixed mode I-II damage scale and double-K fracture parameters. Results indicate that: (1) the coupling effect of freeze-thaw cycles and sulfate erosion exhibits a dual-mechanism behavior, characterized by initial matrix micro-densification followed by accelerated damage propagation, which ultimately culminates in significant deterioration of the fracture bearing capacity of the material. (2) with an increase in freeze-thaw cycles, the accumulated AE energy at peak load, the shear failure ratio, the critical damage scale, and the double-K fracture toughness for both mode I and mixed mode I-II cracks exhibit a consistent pattern of an initial increase followed by a subsequent decrease. (3) compared with mode I fracture, mixed mode I-II fracture exerts effects on the proportion of shear failure, critical damage scale, and cumulative AE energy, whereas it exerts a relatively minor effect on the double-K fracture parameters. (4) in contrast to water freeze-thaw environment, sulfate solution freeze-thaw induces significantly different evolutionary patterns in cumulative AE energy, AF, RA, and b-value

研究了硫酸盐腐蚀和冻融循环对混凝土I-II混合模式损伤和断裂行为的影响。首先，测量了不同冻融循环次数后混凝土梁的质量损失和动弹性模量，并利用NMR和XRD分析了混凝土梁的内部孔隙结构和矿物成分。随后，结合声发射技术对混凝土梁进行了准静荷载下的断裂试验。系统分析了硫酸盐腐蚀和冻融循环作用下声发射能、AF-RA参数和b值的演化规律。最后，采用有限元法对混合模式I-II损伤尺度和双k断裂参数进行了探索。结果表明：(1)冻融循环与硫酸盐侵蚀的耦合作用表现为初始基体微致密化，随后损伤扩展加速，最终导致材料断裂承载能力显著恶化的双机制行为；(2)随着冻融循环次数的增加，ⅰ型和ⅰ-ⅱ型混合裂纹的峰值累积声发射能、剪切破坏比、临界损伤尺度和双k断裂韧性均表现出先增大后减小的规律。(3)与I型断裂相比，I- ii型混合断裂对剪切破坏比例、临界损伤尺度和累积声发射能量有影响，而对双k断裂参数的影响相对较小。(4)与水冻融环境相比，硫酸盐溶液冻融环境对累积声发射能量、AF、RA和b值的演化模式有显著差异

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引用次数: 0

A peridynamic physics-informed U-net transfer learning framework for progressive crack prediction of fiber reinforced composites 基于动态物理的纤维增强复合材料渐进裂纹预测U-net迁移学习框架

IF 5.6 2区工程技术 Q1 ENGINEERING, MECHANICAL

Theoretical and Applied Fracture Mechanics

Pub Date : 2026-01-07 DOI: 10.1016/j.tafmec.2026.105448

Xihong Zhang , Kunpang Kou , Chichiu Lam , Yang Yang

In this paper, a peridynamic physics-informed U-net transfer learning framework is specifically designed for predicting the progressive crack in fiber reinforced composites (FRC). This framework addresses the challenges associated with undefined differentiation at displacement discontinuities that are often encountered in traditional physics-informed neural networks (PINNs). It also tackles the stiffness ill-conditioning that arises from significant differences in material properties between the fiber and the matrix. In the U-net-PINN model, a non-local convolution kernel has been developed based on the non-local characteristics of peridynamics. The introduction of a wavelet activation function further improves the network's convergence efficiency. A specially designed loss function combines the current boundary conditions and the minimum potential energy increment for FRC and fiber bonds derived from bond-based peridynamic with stretch and rotation. By applying the transfer learning technique, the U-net-PINN models are enhanced to predict the crack propagation in the FRC for various fiber directions. Several numerical results demonstrate that the nonlocal U-net-PINN can more accurately identify the crack initiation and propagation in FRC with high accuracy, efficiency, and ease of implementation. Its data-free characteristic enables the nonlocal U-net-PINN framework to predict the crack propagation in FRC, where the traditional numerical method may fall short.

本文针对纤维增强复合材料（FRC）的渐进裂纹预测，设计了一个基于动态物理的U-net迁移学习框架。该框架解决了传统物理信息神经网络（pinn）在位移不连续处经常遇到的未定义微分所带来的挑战。它还解决了由于纤维和基体之间材料特性的显著差异而产生的刚度失调。在U-net-PINN模型中，基于周期动力学的非局部特性，提出了一种非局部卷积核。小波激活函数的引入进一步提高了网络的收敛效率。一个特别设计的损失函数结合了当前边界条件和纤维纤维键的最小势能增量，由基于键的周动力学与拉伸和旋转导出。通过应用迁移学习技术，对U-net-PINN模型进行了改进，以预测纤维纤维纤维中不同方向的裂纹扩展。数值结果表明，非局部U-net-PINN方法能较准确地识别FRC裂纹的萌生和扩展，具有较高的精度、效率和易于实现的特点。它的无数据特性使得非局部U-net-PINN框架能够较好地预测FRC中裂纹的扩展，这是传统数值方法难以实现的。

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引用次数: 0