Engineering Fracture Mechanics最新文献

Effect of shrinkage-induced initial damage on the frost resistance of concrete in cold regions 收缩引起的初始损伤对寒冷地区混凝土抗冻性的影响

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-15 DOI: 10.1016/j.engfracmech.2024.110652

Yanchun Miao , Wanhao Yu , Lin Jin , Liguo Wang , Junlin Lin , Yali Li , Zeyu Lu , Jinyang Jiang

The shrinkage-induced initial damage poses a threat to the frost resistance of concrete in cold regions with low relative humidity (RH). However, the progression of freeze–thaw damage in concrete affected by this initial damage, along with the quantitative relationships among RH, freeze–thaw damage, and the number of freeze–thaw cycles (FTCs), remains unexplored. This study employed combination of experimental and numerical simulation approaches to address these challenges. Experimentally, the freeze–thaw damage of concrete cured at low RH (40 ± 5 %) was compared with that cured at standard RH (95 ± 5 %) after varying FTCs. Results indicated that the former experienced more severe freeze–thaw damage, characterized by increased surface peeling, higher mass loss rate, and greater compressive strength attenuation. For the simulation aspect, a numerical model incorporating cohesive elements was firstly proposed to study the evolution of freeze–thaw damage in concrete cured at different RH under FTCs, of which the rationality was confirmed through experimental data. Additionally, the effect of FTCs and curing RH on freeze–thaw damage was investigated, revealing a negative correlation between freeze–thaw damage and curing RH, resulting in opposite evolution trend for residual mechanical properties of concrete. Finally, the freeze–thaw damage prediction model was proposed based on simulation results, and the error between the predicted and actual values was only 2.1 %, which confirmed that this model can be adopted to accurately assess the freeze–thaw damage degree of concrete cured by different RH after different FTCs. In conclusion, this study aims to better understand the freeze–thaw damage evolution of concrete cured under low RH, which provides a feasible scheme for the frost resistant design of concrete construction in cold regions.

在相对湿度（RH）较低的寒冷地区，收缩引起的初始破坏对混凝土的抗冻性构成威胁。然而，受这种初始损伤影响的混凝土冻融损伤的发展过程，以及相对湿度、冻融损伤和冻融循环次数（FTCs）之间的定量关系仍有待探索。本研究采用实验和数值模拟相结合的方法来应对这些挑战。通过实验，比较了低相对湿度（40 ± 5 %）和标准相对湿度（95 ± 5 %）下养护的混凝土在不同冻融循环次数后的冻融破坏情况。结果表明，前者经历了更严重的冻融破坏，其特点是表面剥落增加、质量损失率更高、抗压强度衰减更大。在模拟方面，首先提出了一个包含内聚元素的数值模型，以研究在不同相对湿度下养护的混凝土在 FTCs 条件下的冻融破坏演变，并通过实验数据证实了该模型的合理性。此外，研究了 FTCs 和养护相对湿度对冻融破坏的影响，发现冻融破坏与养护相对湿度呈负相关，导致混凝土残余力学性能的演变趋势相反。最后，根据模拟结果提出了冻融破坏预测模型，预测值与实际值的误差仅为 2.1%，证实该模型可用于准确评估不同冻融时间后不同相对湿度养护混凝土的冻融破坏程度。总之，本研究旨在更好地了解低相对湿度条件下混凝土养护的冻融破坏演化过程，为寒冷地区混凝土建筑的抗冻设计提供可行方案。

{"title":"Effect of shrinkage-induced initial damage on the frost resistance of concrete in cold regions","authors":"Yanchun Miao , Wanhao Yu , Lin Jin , Liguo Wang , Junlin Lin , Yali Li , Zeyu Lu , Jinyang Jiang","doi":"10.1016/j.engfracmech.2024.110652","DOIUrl":"10.1016/j.engfracmech.2024.110652","url":null,"abstract":"<div><div>The shrinkage-induced initial damage poses a threat to the frost resistance of concrete in cold regions with low relative humidity (RH). However, the progression of freeze–thaw damage in concrete affected by this initial damage, along with the quantitative relationships among RH, freeze–thaw damage, and the number of freeze–thaw cycles (FTCs), remains unexplored. This study employed combination of experimental and numerical simulation approaches to address these challenges. Experimentally, the freeze–thaw damage of concrete cured at low RH (40 ± 5 %) was compared with that cured at standard RH (95 ± 5 %) after varying FTCs. Results indicated that the former experienced more severe freeze–thaw damage, characterized by increased surface peeling, higher mass loss rate, and greater compressive strength attenuation. For the simulation aspect, a numerical model incorporating cohesive elements was firstly proposed to study the evolution of freeze–thaw damage in concrete cured at different RH under FTCs, of which the rationality was confirmed through experimental data. Additionally, the effect of FTCs and curing RH on freeze–thaw damage was investigated, revealing a negative correlation between freeze–thaw damage and curing RH, resulting in opposite evolution trend for residual mechanical properties of concrete. Finally, the freeze–thaw damage prediction model was proposed based on simulation results, and the error between the predicted and actual values was only 2.1 %, which confirmed that this model can be adopted to accurately assess the freeze–thaw damage degree of concrete cured by different RH after different FTCs. In conclusion, this study aims to better understand the freeze–thaw damage evolution of concrete cured under low RH, which provides a feasible scheme for the frost resistant design of concrete construction in cold regions.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110652"},"PeriodicalIF":4.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel method for failure probability prediction of plain weave composites considering loading randomness and dispersion of strength 考虑加载随机性和强度分散性的平纹复合材料失效概率预测新方法

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-15 DOI: 10.1016/j.engfracmech.2024.110649

Bingyao Li , Youming Li , Jingran Ge , Jianguo Wu , Zengwen Wu , Jun Liang

A new method based on combined residual stiffness-strength degradation is developed to predict the failure probability of plain weave composites subjected to random fatigue loadings. All the parameters presented in the proposed analytical model are characterized using the outcomes from quasi-static and constant amplitude fatigue testing. The evolution of residual strength is obtained based on combined residual stiffness-strength degradation model, which can greatly reduce the cost of the experiments. The Weibull distribution with two parameters is used to account for the dispersion of residual strength. Combing with randomness statistics of the fatigue loadings and the interference criterion of stress-strength, the fatigue failure behavior and failure probability are obtained. The narrow-band random vibration experiments were conducted to generate the random loadings and validate the predicted results. The approach proposed in this paper takes full advantage of residual stiffness or residual strength method and has better accuracy.

本文开发了一种基于残余刚度-强度综合退化的新方法，用于预测平织复合材料在随机疲劳载荷作用下的失效概率。利用准静态和恒定振幅疲劳试验的结果对所提出的分析模型中的所有参数进行了表征。残余强度的演变是基于残余刚度-强度退化组合模型得到的，这可以大大降低实验成本。使用带有两个参数的威布尔分布来解释残余强度的分散性。结合疲劳载荷的随机性统计和应力-强度干涉准则，得到疲劳失效行为和失效概率。通过窄带随机振动实验产生随机载荷，并验证了预测结果。本文提出的方法充分利用了残余刚度或残余强度方法的优势，具有更好的精度。

{"title":"A novel method for failure probability prediction of plain weave composites considering loading randomness and dispersion of strength","authors":"Bingyao Li , Youming Li , Jingran Ge , Jianguo Wu , Zengwen Wu , Jun Liang","doi":"10.1016/j.engfracmech.2024.110649","DOIUrl":"10.1016/j.engfracmech.2024.110649","url":null,"abstract":"<div><div>A new method based on combined residual stiffness-strength degradation is developed to predict the failure probability of plain weave composites subjected to random fatigue loadings. All the parameters presented in the proposed analytical model are characterized using the outcomes from quasi-static and constant amplitude fatigue testing. The evolution of residual strength is obtained based on combined residual stiffness-strength degradation model, which can greatly reduce the cost of the experiments. The Weibull distribution with two parameters is used to account for the dispersion of residual strength. Combing with randomness statistics of the fatigue loadings and the interference criterion of stress-strength, the fatigue failure behavior and failure probability are obtained. The narrow-band random vibration experiments were conducted to generate the random loadings and validate the predicted results. The approach proposed in this paper takes full advantage of residual stiffness or residual strength method and has better accuracy.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110649"},"PeriodicalIF":4.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multiaxial failure of dual-phase elastomeric composites 双相弹性复合材料的多轴失效

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-14 DOI: 10.1016/j.engfracmech.2024.110625

Mohit Goswami , Piyush Gupta , Yoav Lev , Santanu Chattopadhyay , Konstantin Volokh

The natural rubber (NR) and styrene butadiene rubber (SBR) based composites are used in several industrial applications, mainly tires. The mechanical properties can be tailored by blending them in appropriate ratios. In the present study, blended polymer–matrix composites are tested for uniaxial and bulge tests. Simultaneous constitutive modeling with failure description is done for uniaxial and equibiaxial test results. Using the computational modeling we study the problem of cavitation and compare these results with morphological analysis. The finite element analysis (FEA) is used to analyze state of stress throughout the bulge. We find that the rubber composites can behave contradictorily under different types of mechanical testing environments. For instance, the pressure at failure for SBR composite is found to be 3% more than NR composite under bulge test. However, tensile strength of NR composite is found to 40% more than that of SBR composite, when tested uniaxially. The critical hydrostatic tension corresponding to onset of cavitation is observed to decreasing by more than 20% when NR composite is compared with SBR composite. The dual phase rubber composite with 25% NR and 75% SBR exhibits better mechanical properties, when compared with other blended composites.

以天然橡胶（NR）和丁苯橡胶（SBR）为基础的复合材料被广泛应用于多种工业领域，主要是轮胎。通过以适当的比例混合这两种材料，可以定制其机械性能。本研究对共混聚合物基复合材料进行了单轴和隆起试验。针对单轴和等轴测试结果，同时进行了结构建模和失效描述。通过计算建模，我们研究了空化问题，并将这些结果与形态分析进行了比较。有限元分析（FEA）用于分析整个隆起的应力状态。我们发现，在不同类型的机械测试环境下，橡胶复合材料的表现会相互矛盾。例如，在隆起试验中，SBR 复合材料的破坏压力比 NR 复合材料高 3%。然而，在单轴测试中，发现 NR 复合材料的拉伸强度比 SBR 复合材料高 40%。与丁苯橡胶复合材料相比，NR 复合材料对应于空化开始时的临界静水压力降低了 20% 以上。与其他共混复合材料相比，含有 25% NR 和 75% SBR 的双相橡胶复合材料具有更好的机械性能。

{"title":"Multiaxial failure of dual-phase elastomeric composites","authors":"Mohit Goswami , Piyush Gupta , Yoav Lev , Santanu Chattopadhyay , Konstantin Volokh","doi":"10.1016/j.engfracmech.2024.110625","DOIUrl":"10.1016/j.engfracmech.2024.110625","url":null,"abstract":"<div><div>The natural rubber (NR) and styrene butadiene rubber (SBR) based composites are used in several industrial applications, mainly tires. The mechanical properties can be tailored by blending them in appropriate ratios. In the present study, blended polymer–matrix composites are tested for uniaxial and bulge tests. Simultaneous constitutive modeling with failure description is done for uniaxial and equibiaxial test results. Using the computational modeling we study the problem of cavitation and compare these results with morphological analysis. The finite element analysis (FEA) is used to analyze state of stress throughout the bulge. We find that the rubber composites can behave contradictorily under different types of mechanical testing environments. For instance, the pressure at failure for SBR composite is found to be 3% more than NR composite under bulge test. However, tensile strength of NR composite is found to 40% more than that of SBR composite, when tested uniaxially. The critical hydrostatic tension corresponding to onset of cavitation is observed to decreasing by more than 20% when NR composite is compared with SBR composite. The dual phase rubber composite with 25% NR and 75% SBR exhibits better mechanical properties, when compared with other blended composites.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110625"},"PeriodicalIF":4.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Predicting fracture strength of polarized GaN semiconductive ceramics under combined mechanical-current loading 预测机械-电流联合加载下极化氮化镓半导体陶瓷的断裂强度

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-14 DOI: 10.1016/j.engfracmech.2024.110655

GuoShuai Qin , ShiJie Wang , ZhenYu Wang , MingKai Guo , CuiYing Fan , MingHao Zhao , Chunsheng Lu

Gallium nitride (GaN) piezoelectric semiconductor ceramics (PSCs) structures are often subjected to combined mechanical and electrical fields in engineering applications, leading to complex deformation and fracture challenges. This paper presents a fracture predictive model for PSCs under combined mechanical and electrical loading, developed using the boundary effect model rather than relying solely on data fitting. By introducing a current parameter that influences the characteristic crack length, the model effectively predicts the quasi-brittle fracture characteristics of GaN PSCs. Additionally, the model reveals how electric current affects the quasi-brittle fracture behavior of PSCs, providing crucial theoretical support for the reliable design of GaN intelligent semiconductor structures in complex environments.

氮化镓（GaN）压电半导体陶瓷（PSCs）结构在工程应用中经常受到机械和电场的共同作用，从而导致复杂的变形和断裂难题。本文利用边界效应模型，而不是仅仅依赖数据拟合，为 PSCs 提出了一个在机械和电气联合加载下的断裂预测模型。通过引入影响特征裂纹长度的电流参数，该模型可有效预测 GaN PSC 的准脆性断裂特征。此外，该模型还揭示了电流如何影响 PSC 的准脆性断裂行为，为在复杂环境中可靠地设计 GaN 智能半导体结构提供了重要的理论支持。

引用次数: 0

Experimental and numerical investigation on the failure behaviors of laminates with various shaped cutouts under tensile loading 拉伸载荷下带有不同形状切口的层压板破坏行为的实验和数值研究

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-13 DOI: 10.1016/j.engfracmech.2024.110646

Zhengliang Liu , Leilei Yan , Zhen Wu , Jie Zhou

Composite structures in aircraft often contain many cutouts, and failure of these structures is prone to occur near the edge of cutouts. Therefore, the failure behaviors of laminates with various shaped cutouts should be carefully investigated. To this end, experiments and numerical simulations are employed to investigate this issue. The tensile tests of composite laminates with circular, elliptical, square, and rectangular cutouts were carried out. Digital image correlation was utilized to capture the strain fields around the cutout. Combining the strain failure criterion and the modified exponential damage variables, a three-dimensional progressive damage model was established, which can accurately predict the peak loads of composite laminates with diverse cutouts. All errors between the experimental and numerical results are less than 10 %. The experimental and numerical results indicate that the shape of the cutout has a great influence on the peak loads. As the ratio of major axis to minor axis (a/b) is increased from 1 to 5, peak loads obviously increase for the laminates with elliptical cutouts. Experimental results show that the average peak load of the laminates with elliptical cutout (a/b = 4) is 20.0 % higher than that of the laminates with circular cutout (a/b = 1). The dispersed distribution of high strains near the edge of the cutout results in an improvement of bearing capacity. As the ratio of length to width (l/w) in rectangular cutouts is increased from 0.5 to 3, peak loads are also improved obviously, because experimental results show that the average peak load of the laminates with rectangular cutout (l/w = 0.5) is 12.3 % lower than that of the laminates with square cutout (l/w = 1). Therefore, to improve the peak loads, it is very necessary to select the proper ratios of a/b and l/w. The above conclusions can serve as a reference for the design of composite structures.

飞机中的复合材料结构通常包含许多切口，这些结构的失效容易发生在切口边缘附近。因此，应仔细研究具有各种形状切口的层压板的失效行为。为此，我们采用了实验和数值模拟来研究这一问题。对带有圆形、椭圆形、正方形和长方形切口的复合材料层压板进行了拉伸试验。利用数字图像相关技术捕捉切口周围的应变场。结合应变破坏准则和修正的指数破坏变量，建立了一个三维渐进破坏模型，该模型可以准确预测具有不同切口的复合材料层压板的峰值载荷。实验结果与数值结果之间的误差均小于 10%。实验和数值结果表明，切口形状对峰值载荷有很大影响。当主轴与小轴之比（a/b）从 1 增加到 5 时，椭圆形切口层压板的峰值载荷明显增加。实验结果表明，椭圆形切口（a/b = 4）层压板的平均峰值载荷比圆形切口（a/b = 1）层压板高 20.0%。高应变在切口边缘附近的分散分布提高了承载能力。当矩形切口的长宽比（l/w）从 0.5 增加到 3 时，峰值载荷也会得到明显改善，因为实验结果表明，矩形切口（l/w = 0.5）层压板的平均峰值载荷比正方形切口（l/w = 1）层压板低 12.3%。因此，要提高峰值载荷，就必须选择适当的 a/b 和 l/w 比。上述结论可作为复合材料结构设计的参考。

{"title":"Experimental and numerical investigation on the failure behaviors of laminates with various shaped cutouts under tensile loading","authors":"Zhengliang Liu , Leilei Yan , Zhen Wu , Jie Zhou","doi":"10.1016/j.engfracmech.2024.110646","DOIUrl":"10.1016/j.engfracmech.2024.110646","url":null,"abstract":"<div><div>Composite structures in aircraft often contain many cutouts, and failure of these structures is prone to occur near the edge of cutouts. Therefore, the failure behaviors of laminates with various shaped cutouts should be carefully investigated. To this end, experiments and numerical simulations are employed to investigate this issue. The tensile tests of composite laminates with circular, elliptical, square, and rectangular cutouts were carried out. Digital image correlation was utilized to capture the strain fields around the cutout. Combining the strain failure criterion and the modified exponential damage variables, a three-dimensional progressive damage model was established, which can accurately predict the peak loads of composite laminates with diverse cutouts. All errors between the experimental and numerical results are less than 10 %. The experimental and numerical results indicate that the shape of the cutout has a great influence on the peak loads. As the ratio of major axis to minor axis (<em>a</em>/<em>b</em>) is increased from 1 to 5, peak loads obviously increase for the laminates with elliptical cutouts. Experimental results show that the average peak load of the laminates with elliptical cutout (<em>a</em>/<em>b</em> = 4) is 20.0 % higher than that of the laminates with circular cutout (<em>a</em>/<em>b</em> = 1). The dispersed distribution of high strains near the edge of the cutout results in an improvement of bearing capacity. As the ratio of length to width (<em>l</em>/<em>w</em>) in rectangular cutouts is increased from 0.5 to 3, peak loads are also improved obviously, because experimental results show that the average peak load of the laminates with rectangular cutout (<em>l</em>/<em>w</em> = 0.5) is 12.3 % lower than that of the laminates with square cutout (<em>l</em>/<em>w</em> = 1). Therefore, to improve the peak loads, it is very necessary to select the proper ratios of <em>a</em>/<em>b</em> and <em>l</em>/<em>w.</em> The above conclusions can serve as a reference for the design of composite structures.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110646"},"PeriodicalIF":4.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comprehensive analysis of mode-I cracking in ice: Exploring full-range rate dependency 全面分析冰中的 I 型裂纹：探索全范围速率依赖性

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-13 DOI: 10.1016/j.engfracmech.2024.110650

Fuxin Rui , Jiaqing Dong , Xindong Wei , Yan Huang , Gao-Feng Zhao

Ice, as a crystalline material, demonstrates a unique response in its mode-I fracture toughness to variations in loading rates, characterized by an initial decrease and subsequent increase in toughness. This phenomenon has been explored in limited studies. In this work, an extensive numerical analysis of mode-I ice cracking is conducted by using the distinct lattice spring model (DLSM). Norton-Bailey Drucker-Prager DLSM (NB-DP-DLSM) is initially employed to investigate the classical explanations of creep and stress relaxation for the anomaly observed in ice’s fracture toughness at lower loading rates, but this approach does not successfully replicate the experimentally observed strain rate dependency. Then, two rate-dependent constitutive models are introduced to further examine the mode-I fracture mechanics of ice. Our numerical simulations of three-point bending tests show that the relationship between fracture toughness and strain rate at lower levels is more accurately captured by rate-dependent models. For higher strain rates, our numerical modeling of notched semi-circular bending tests indicates that a rate-independent constitutive model can replicate the loading rate dependency of ice’s mode-I fracture toughness. In conclusion, these observations suggest that a reverse-stage-like dynamic constitutive model for DLSM can potentially capture the full range of loading rate dependencies observed in ice.

冰作为一种结晶材料，其 I 型断裂韧性对加载速率变化有独特的反应，其特点是韧性最初降低，随后升高。对这一现象的研究还很有限。在这项工作中，我们使用独特的晶格弹簧模型（DLSM）对模态 I 冰裂纹进行了广泛的数值分析。最初采用 Norton-Bailey Drucker-Prager DLSM（NB-DP-DLSM）来研究蠕变和应力松弛对冰在较低加载速率下断裂韧性异常现象的经典解释，但这种方法并不能成功复制实验观察到的应变速率依赖性。随后，我们引入了两个与速率相关的构成模型，以进一步研究冰的 I 模断裂力学。我们对三点弯曲试验进行的数值模拟表明，依赖速率的模型能更准确地捕捉到低水平断裂韧性与应变速率之间的关系。对于较高的应变速率，我们对缺口半圆形弯曲试验的数值模拟表明，与速率无关的构成模型可以复制冰的 I 型断裂韧性与加载速率的关系。总之，这些观察结果表明，用于 DLSM 的反向阶段式动态构造模型有可能捕捉到在冰中观察到的全部加载速率依赖性。

{"title":"Comprehensive analysis of mode-I cracking in ice: Exploring full-range rate dependency","authors":"Fuxin Rui , Jiaqing Dong , Xindong Wei , Yan Huang , Gao-Feng Zhao","doi":"10.1016/j.engfracmech.2024.110650","DOIUrl":"10.1016/j.engfracmech.2024.110650","url":null,"abstract":"<div><div>Ice, as a crystalline material, demonstrates a unique response in its mode-I fracture toughness to variations in loading rates, characterized by an initial decrease and subsequent increase in toughness. This phenomenon has been explored in limited studies. In this work, an extensive numerical analysis of mode-I ice cracking is conducted by using the distinct lattice spring model (DLSM). Norton-Bailey Drucker-Prager DLSM (NB-DP-DLSM) is initially employed to investigate the classical explanations of creep and stress relaxation for the anomaly observed in ice’s fracture toughness at lower loading rates, but this approach does not successfully replicate the experimentally observed strain rate dependency. Then, two rate-dependent constitutive models are introduced to further examine the mode-I fracture mechanics of ice. Our numerical simulations of three-point bending tests show that the relationship between fracture toughness and strain rate at lower levels is more accurately captured by rate-dependent models. For higher strain rates, our numerical modeling of notched semi-circular bending tests indicates that a rate-independent constitutive model can replicate the loading rate dependency of ice’s mode-I fracture toughness. In conclusion, these observations suggest that a reverse-stage-like dynamic constitutive model for DLSM can potentially capture the full range of loading rate dependencies observed in ice.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110650"},"PeriodicalIF":4.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

An enhanced Hosford–Coulomb fracture model for predicting ductile fracture under a wide range of stress states 用于预测各种应力状态下韧性断裂的增强型霍斯福德-库仑断裂模型

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-12 DOI: 10.1016/j.engfracmech.2024.110635

Yuze Song , Yuhao Guo , Gang Liu , Jinbo Han , Shichao Wang , Weiping He , Shiyang Zhu

In this study, an Enhanced Hosford–Coulomb (EHC) fracture model is proposed, which suits a wide range of stress states. The model is validated by quantitatively investigating the ductile fracture behaviors of Ti-6Al-3Nb-2Zr-1Mo titanium alloy through experiments and numerical simulations, and the fracture morphologies are characterized using scanning electron microscopy. The results show that the EHC model has higher accuracy in predicting ductile fracture strain for Ti-6Al-3Nb-2Zr-1Mo alloy compared to the original Hosford–Coulomb (HC) model. Finally, the accuracy and material applicability of the EHC model are further verified with X80 pipeline steel and AA2024-T351 aluminum alloy, demonstrating its advantages.

本研究提出了适用于多种应力状态的增强型霍斯福德-库仑（EHC）断裂模型。通过实验和数值模拟定量研究了 Ti-6Al-3Nb-2Zr-1Mo 钛合金的韧性断裂行为，验证了该模型，并利用扫描电子显微镜对断口形貌进行了表征。结果表明，与原始的 Hosford-Coulomb (HC) 模型相比，EHC 模型在预测 Ti-6Al-3Nb-2Zr-1Mo 合金的韧性断裂应变方面具有更高的准确性。最后，用 X80 管线钢和 AA2024-T351 铝合金进一步验证了 EHC 模型的准确性和材料适用性，证明了其优势。

引用次数: 0

Effective stress intensity factor range for fatigue cracks propagating in mixed mode I-II loading I-II 混合模式加载下疲劳裂纹扩展的有效应力强度因子范围

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-12 DOI: 10.1016/j.engfracmech.2024.110641

Shuancheng Wang , Shuwei Zhou , Bing Yang , Shoune Xiao , Guangwu Yang , Tao Zhu

The actual service axles are often subjected to mixed-mode loading, and predicting the mixed-mode I-II crack propagation behaviour using the mode I effective stress intensity factor (ΔK_I) differs from the real service conditions. To effectively predict the fatigue crack propagation behaviour of actual service structures, the I-II stress intensity factor range (ΔK_P-R) considering two closure effects was adopted to describe the fatigue crack propagation under mixed mode loading. A test database was established based on monitoring data of mode I and mixed-mode I-II (30/45/60°) crack propagation tests under different stress ratios. Combining domain knowledge and symbolic regression (SR) methods, an angle factor was proposed for constructing correlation functions between ΔK_I and ΔK_P-R. The results showed that the loading angle (α) only affects the initial projection of the load parallel and perpendicular to the fatigue crack growth (FCG) direction. Compared with the geometric correction factor, the correlation function acquired by the angle factor constructed by the SR method has higher accuracy, and the balance parameters (SCORE) obtained by the former are significantly higher than those obtained by the latter under the same function complexity. The SR verification results demonstrated that constructing mode I and I-II correlation functions with angle factors has a good predictive effect.

实际使用的车轴通常承受混合模式加载，使用模式 I 有效应力强度因子 (ΔKI) 预测混合模式 I-II 裂纹扩展行为与实际使用条件存在差异。为有效预测实际使用结构的疲劳裂纹扩展行为，采用考虑两种闭合效应的 I-II 应力强度因子范围 (ΔKP-R) 来描述混合模式加载下的疲劳裂纹扩展。根据不同应力比下模式 I 和混合模式 I-II（30/45/60°）裂纹扩展试验的监测数据，建立了一个试验数据库。结合领域知识和符号回归 (SR) 方法，提出了一个角度因子，用于构建 ΔKI 和 ΔKP-R 之间的相关函数。结果表明，加载角度（α）只影响荷载平行于疲劳裂纹生长（FCG）方向和垂直于疲劳裂纹生长（FCG）方向的初始投影。与几何修正系数相比，用 SR 方法构建的角度系数获得的相关函数具有更高的精度，在相同函数复杂度下，前者获得的平衡参数（SCORE）明显高于后者。SR 验证结果表明，用角度因子构建模式 I 和 I-II 关联函数具有良好的预测效果。

{"title":"Effective stress intensity factor range for fatigue cracks propagating in mixed mode I-II loading","authors":"Shuancheng Wang , Shuwei Zhou , Bing Yang , Shoune Xiao , Guangwu Yang , Tao Zhu","doi":"10.1016/j.engfracmech.2024.110641","DOIUrl":"10.1016/j.engfracmech.2024.110641","url":null,"abstract":"<div><div>The actual service axles are often subjected to mixed-mode loading, and predicting the mixed-mode I-II crack propagation behaviour using the mode I effective stress intensity factor (Δ<em>K</em><sub>I</sub>) differs from the real service conditions. To effectively predict the fatigue crack propagation behaviour of actual service structures, the I-II stress intensity factor range (Δ<em>K</em><sub>P-R</sub>) considering two closure effects was adopted to describe the fatigue crack propagation under mixed mode loading. A test database was established based on monitoring data of mode I and mixed-mode I-II (30/45/60°) crack propagation tests under different stress ratios. Combining domain knowledge and symbolic regression (SR) methods, an angle factor was proposed for constructing correlation functions between Δ<em>K</em><sub>I</sub> and Δ<em>K</em><sub>P-R</sub>. The results showed that the loading angle (<em>α</em>) only affects the initial projection of the load parallel and perpendicular to the fatigue crack growth (FCG) direction. Compared with the geometric correction factor, the correlation function acquired by the angle factor constructed by the SR method has higher accuracy, and the balance parameters (SCORE) obtained by the former are significantly higher than those obtained by the latter under the same function complexity. The SR verification results demonstrated that constructing mode I and I-II correlation functions with angle factors has a good predictive effect.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110641"},"PeriodicalIF":4.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Coupling effects of loading rate and temperature on mode I dynamic fracture characteristics of ductile cast iron 加载速率和温度对球墨铸铁 I 型动态断裂特性的耦合效应

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-12 DOI: 10.1016/j.engfracmech.2024.110651

Changzeng Fan , Kaili Qi , Zhou Zhou , Zejian Xu , Mengyu Su , Zhicheng Cai , Yan Liu , Fenglei Huang

Engineering structures made of ductile cast iron (DCI) have a potential risk of failure due to extreme service environments such as high velocity impacts and sub-zero temperatures. Therefore, it is of great importance to investigate the dynamic fracture behavior of DCI under the coupling effect of rate and temperature. In this paper, two sets of impact velocities (5 m/s and 13.5 m/s), and four sets of temperatures (20 °C, −40 °C, −60 °C, and −80 °C) were specially designed to investigate the coupling effect on the mode I dynamic fracture toughness (DFT). The results show that DFT is positively correlated with impact velocity at 20 °C, −40 °C and −60 °C. However, at −80 °C, the rate effect is reversed. Moreover, DFT decreases with decreasing temperature regardless of impact velocity. With microscopic analysis, the phenomenon of ductile–brittle transition (DBT) was observed in the failure of the material, and it’s verified by dynamic tensile tests. The ductile–brittle transition temperature (DBTT) of DCI is determined as −39.7 °C by comparing the DFT with the strain energy density (SED) characterization method.

由球墨铸铁（DCI）制成的工程结构在高速冲击和零下温度等极端使用环境下具有潜在的失效风险。因此，研究球墨铸铁在速度和温度耦合效应下的动态断裂行为具有重要意义。本文专门设计了两组冲击速度（5 m/s和13.5 m/s）和四组温度（20 °C、-40 °C、-60 °C和-80 °C）来研究模式I动态断裂韧性（DFT）的耦合效应。结果表明，在 20 ℃、-40 ℃ 和 -60 ℃ 时，DFT 与冲击速度呈正相关。然而，在-80 °C时，速度效应则相反。此外，无论冲击速度如何，DFT 都会随着温度的降低而减小。通过微观分析，在材料失效过程中观察到了韧性-脆性转变（DBT）现象，并通过动态拉伸试验得到了验证。通过比较 DFT 和应变能密度（SED）表征方法，确定 DCI 的韧性-脆性转变温度（DBTT）为 -39.7°C。

{"title":"Coupling effects of loading rate and temperature on mode I dynamic fracture characteristics of ductile cast iron","authors":"Changzeng Fan , Kaili Qi , Zhou Zhou , Zejian Xu , Mengyu Su , Zhicheng Cai , Yan Liu , Fenglei Huang","doi":"10.1016/j.engfracmech.2024.110651","DOIUrl":"10.1016/j.engfracmech.2024.110651","url":null,"abstract":"<div><div>Engineering structures made of ductile cast iron (DCI) have a potential risk of failure due to extreme service environments such as high velocity impacts and sub-zero temperatures. Therefore, it is of great importance to investigate the dynamic fracture behavior of DCI under the coupling effect of rate and temperature. In this paper, two sets of impact velocities (5 m/s and 13.5 m/s), and four sets of temperatures (20 °C, −40 °C, −60 °C, and −80 °C) were specially designed to investigate the coupling effect on the mode I dynamic fracture toughness (DFT). The results show that DFT is positively correlated with impact velocity at 20 °C, −40 °C and −60 °C. However, at −80 °C, the rate effect is reversed. Moreover, DFT decreases with decreasing temperature regardless of impact velocity. With microscopic analysis, the phenomenon of ductile–brittle transition (DBT) was observed in the failure of the material, and it’s verified by dynamic tensile tests. The ductile–brittle transition temperature (DBTT) of DCI is determined as −39.7 °C by comparing the DFT with the strain energy density (SED) characterization method.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110651"},"PeriodicalIF":4.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of steam curing on cyclic triaxial characteristics of recycled aggregate concrete: Experimental analysis and DEM simulation 蒸汽养护对再生骨料混凝土循环三轴特性的影响：实验分析与 DEM 模拟

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2024-11-12 DOI: 10.1016/j.engfracmech.2024.110643

Xiangyi Zhu , Peng Lei , Xudong Chen , Jingwu Bu

The engineering application of steam-cured recycled aggregate concrete (often in a cyclic triaxial stress state) can not only improve the recycling efficiency of resources, but also accelerate the construction progress. In this paper, we adopt a combination of laboratory experiments, theoretical analysis and numerical simulation to study the cyclic triaxial characteristics of recycled aggregate concrete (RAC) under different curing regimes (20℃, 40℃, 60℃ and 80℃). The results indicate that as the steam curing temperature increases, the internal damage caused by high temperature continues to intensify, and the cyclic triaxial failure mode of RAC transitions from shear failure to compression failure, and its peak strength, dynamic elastic modulus, and dilatancy angle all show a downward trend. A linear prediction model is established based on the strong correlation between peak strength and steam curing temperature. As the loading cycles increase, the dynamic elastic modulus and dilatancy angle of RAC show exponential and linear downward trends respectively, and the decline rate increases with the increase of steam curing temperature, and the prediction models for dynamic elastic modulus and dilatancy angle are established based on quantitative relationships between variables. On the basis of experimental analysis results, a cyclic triaxial DEM model considering real recycled aggregates is established by introducing steam-cured damage indexes into the mesoscopic parameters, and its applicability in predicting cyclic triaxial mechanical properties of RAC under different curing regimes is verified. The research outcomes can save a lot of test cost and time consumption for developing steam-cured concrete with better performance, and have important theoretical guidance and practical significance for the wide application of steam-cured concrete.

蒸汽养护再生骨料混凝土（通常处于循环三轴应力状态）的工程应用不仅能提高资源的循环利用效率，还能加快施工进度。本文采用实验室实验、理论分析和数值模拟相结合的方法，研究了再生骨料混凝土（RAC）在不同养护制度（20℃、40℃、60℃和 80℃）下的循环三轴特性。结果表明，随着蒸汽固化温度的升高，高温造成的内部破坏不断加剧，RAC 的循环三轴破坏模式从剪切破坏过渡到压缩破坏，其峰值强度、动态弹性模量和膨胀角均呈下降趋势。根据峰值强度与蒸汽固化温度之间的强相关性，建立了一个线性预测模型。随着加载周期的增加，RAC 的动弹性模量和扩张角分别呈指数和线性下降趋势，且下降率随蒸汽固化温度的增加而增加，并根据变量间的定量关系建立了动弹性模量和扩张角的预测模型。在实验分析结果的基础上，通过在中观参数中引入蒸汽固化损伤指标，建立了考虑真实再生骨料的循环三轴 DEM 模型，并验证了其在预测不同固化制度下 RAC 循环三轴力学性能中的适用性。研究成果可为开发性能更优的蒸养混凝土节省大量试验成本和时间消耗，对蒸养混凝土的广泛应用具有重要的理论指导和实践意义。

{"title":"Influence of steam curing on cyclic triaxial characteristics of recycled aggregate concrete: Experimental analysis and DEM simulation","authors":"Xiangyi Zhu , Peng Lei , Xudong Chen , Jingwu Bu","doi":"10.1016/j.engfracmech.2024.110643","DOIUrl":"10.1016/j.engfracmech.2024.110643","url":null,"abstract":"<div><div>The engineering application of steam-cured recycled aggregate concrete (often in a cyclic triaxial stress state) can not only improve the recycling efficiency of resources, but also accelerate the construction progress. In this paper, we adopt a combination of laboratory experiments, theoretical analysis and numerical simulation to study the cyclic triaxial characteristics of recycled aggregate concrete (RAC) under different curing regimes (20℃, 40℃, 60℃ and 80℃). The results indicate that as the steam curing temperature increases, the internal damage caused by high temperature continues to intensify, and the cyclic triaxial failure mode of RAC transitions from shear failure to compression failure, and its peak strength, dynamic elastic modulus, and dilatancy angle all show a downward trend. A linear prediction model is established based on the strong correlation between peak strength and steam curing temperature. As the loading cycles increase, the dynamic elastic modulus and dilatancy angle of RAC show exponential and linear downward trends respectively, and the decline rate increases with the increase of steam curing temperature, and the prediction models for dynamic elastic modulus and dilatancy angle are established based on quantitative relationships between variables. On the basis of experimental analysis results, a cyclic triaxial DEM model considering real recycled aggregates is established by introducing steam-cured damage indexes into the mesoscopic parameters, and its applicability in predicting cyclic triaxial mechanical properties of RAC under different curing regimes is verified. The research outcomes can save a lot of test cost and time consumption for developing steam-cured concrete with better performance, and have important theoretical guidance and practical significance for the wide application of steam-cured concrete.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"312 ","pages":"Article 110643"},"PeriodicalIF":4.7,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0