Theoretical and Applied Fracture Mechanics最新文献_第6页

Utilization of High-Temperature miniaturized testing to Assist in life management for gas turbine Blades: An Overview 利用高温微型化测试协助燃气轮机叶片的寿命管理：概述

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-26 DOI: 10.1016/j.tafmec.2024.104697

引用次数: 0

Weakly confined slotted cartridge blasting in jointed rock mass 在节理岩体中进行弱约束开槽装药爆破

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-24 DOI: 10.1016/j.tafmec.2024.104695

{"title":"Weakly confined slotted cartridge blasting in jointed rock mass","authors":"","doi":"10.1016/j.tafmec.2024.104695","DOIUrl":"10.1016/j.tafmec.2024.104695","url":null,"abstract":"<div><div>Directional fracture blasting can improve the smooth blasting effect of layered jointed rock masses. However, few studies have comprehensively considered the interaction between joints and slit blasting, and there is a lack of quantitative research and analysis on slit blasting. Therefore, this study combined slit blasting, pouring model test blocks for explosion testing, and numerical simulations for auxiliary research. Finally, practical engineering applications were conducted. The results showed that the weakly constrained PVC material has a high instantaneous strength under impact and can achieve a good energy accumulation guidance effect. The joint angle has a significant impact on the isolation effect of explosion stress and crack propagation. The isolation effect of the explosion stress gradually weakened with an increase in joint angle. The smaller the angle, the more vulnerable the crack propagation direction is to the “traction” of the joint and tends to the trend of the joint, and the more serious the phenomenon of crack turning, deviation and bifurcation. The results show that the explosion energy propagates preferentially from the cutting seam direction, and the stress in the cutting seam direction reaches the peak value first. The energy in the cutting seam direction has a strong transmission ability and a directional fracture effect on the joints, and the application of weakly restrained slotted pipes in layered rock tunnel blasting construction has a good effect.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418853","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

Analysis of the fracture response of anchored rock under three-point bending from experimental and numerical perspectives 从实验和数值角度分析三点弯曲下锚固岩石的断裂响应

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-23 DOI: 10.1016/j.tafmec.2024.104692

{"title":"Analysis of the fracture response of anchored rock under three-point bending from experimental and numerical perspectives","authors":"","doi":"10.1016/j.tafmec.2024.104692","DOIUrl":"10.1016/j.tafmec.2024.104692","url":null,"abstract":"<div><div>The stability and bearing capacity of fractured surrounding rock in underground engineering are affected by the support conditions. In this study, an anchored rock unit was selected as an object for fracture mechanics three-point bending tests by varying the anchorage position. The results showed that the fracture toughness (<em>K</em><sub>IC</sub>) of the anchored specimens showed a decreasing trend with the increase in the distance of the bolt center from the crack tip (<em>D</em><sub>a</sub>), while exhibiting an increase of 21.18 ∼ 135.32 % in comparison to the unanchored specimens. The change in axial force of the bolt with time can be classified into three stages: initial change, significant elevation, and liner increase. Besides, the sensitivity of the anchored specimens to the crack opening distance was significantly reduced and the ultimate tensile strains were commonly larger than the unanchored. Meanwhile, a numerical model consistent with the properties of the medium was developed using the PFC-FLAC coupling method. The simulation results show that the anchorage position and preload influence the mechanical parameters such as <em>K</em><sub>IC</sub> and the bolt-enhanced fracture energy (<em>G</em><sub>b</sub>), while improving the stress concentration phenomenon at the crack tip.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142327198","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 improved phase-field model for oil–water two-phase flow and mixed-mode fracture propagation in hydraulic fracturing 水力压裂中油水两相流和混合模式裂缝传播的改进相场模型

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-21 DOI: 10.1016/j.tafmec.2024.104677

{"title":"An improved phase-field model for oil–water two-phase flow and mixed-mode fracture propagation in hydraulic fracturing","authors":"","doi":"10.1016/j.tafmec.2024.104677","DOIUrl":"10.1016/j.tafmec.2024.104677","url":null,"abstract":"<div><div>An improved novel phase-field model is proposed for describing fracture propagation, effectively characterizing the interactions between oil–water two-phase fluids and solids as well as mixed-mode fracturing. This model encompasses equations for two-phase flow stress balance, fluid flow, and a complex mode fracture phase-field specific to two-phase flow. Within the fluid flow equations, the capillary pressure caused by the oil–water interface during the fluid loss process in the matrix is accounted for, and the anisotropic relative permeability during fluid flow is linked to normalized saturation. The driving forces for fracture propagation in the phase-field are categorized into Mode I and Mode II forces, with the contribution from the oil–water two-phase fluid attributed to the Mode I (tensile) driving force. The model uses finite element numerical discretization and the Newton-Raphson iterative method to establish a numerical iteration format, employing an implicit-explicit staggered solution scheme. Additionally, the model is used to investigate several key factors. It assesses the impact of different intersection angles on fracture propagation in naturally porous media. It also studies the effect of different natural fracture permeabilities on hydraulic fracture propagation. Finally, the model analyzes the propagation patterns of hydraulic fractures under different perforation phase angles.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359509","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

The characteristics of hydraulic fracture morphology in glutenite reservoirs: An experimental investigation 糯质岩储层水力压裂形态特征：实验研究

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-21 DOI: 10.1016/j.tafmec.2024.104685

{"title":"The characteristics of hydraulic fracture morphology in glutenite reservoirs: An experimental investigation","authors":"","doi":"10.1016/j.tafmec.2024.104685","DOIUrl":"10.1016/j.tafmec.2024.104685","url":null,"abstract":"<div><div>Hydraulic fracturing efficiently unlocks the vast energy potential of glutenite, a crucial unconventional tight oil/gas reservoir. However, the characteristics of the hydraulic fracture (HF) morphology is complex and remains unclear in highly heterogeneous glutenite reservoirs. It is challenging to design fracturing schemes effectively. In this work, rock mechanics experiments and ten groups of true triaxial hydraulic fracturing experiments were carried out to investigate the HF morphology. Critical factors such as horizontal stress difference (HSD), injection rate, fluid viscosity, gravel volume content, and gravel size were investigated. Based on computed tomography (CT) scanning technology, this work innovatively established a three-dimensional fracture characterization method in glutenite samples to observe fracture morphology. The results indicate that in glutenite reservoirs, the initiation positions of HF typically exhibit randomness, often occurring at multiple asymmetric points. The propagation directions of HF are influenced by both HSD and formation heterogeneity, frequently deviating from the direction of the maximum principal stress. The propagation behavior of HF encountering gravel mainly manifests as penetration and deflection. These behaviors are co-controlled by the penetration capability of HF and the shielding effect of gravel. Furthermore, under conditions of low HSD, high injection rate, low fluid viscosity, and large gravel size, HF morphology is more complex, with a high tendency to generate branched fractures. The initiation pressure is positively correlated with HSD, injection rate, and fracturing fluid viscosity, and negatively correlated with gravel content. This study provides a theoretical basis for the optimization of fracturing designs in glutenite reservoirs.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142323132","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 experimental study of fracture mechanism and morphology of granite specimens under various dynamic loading rates 不同动态加载速率下花岗岩试样断裂机理和形态的实验研究

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-20 DOI: 10.1016/j.tafmec.2024.104687

{"title":"An experimental study of fracture mechanism and morphology of granite specimens under various dynamic loading rates","authors":"","doi":"10.1016/j.tafmec.2024.104687","DOIUrl":"10.1016/j.tafmec.2024.104687","url":null,"abstract":"<div><div>Numerous studies have shown that dynamic fracture toughness (DFT) of rock is dependent on loading rate. This paper quantitatively studied the effect of loading rate on DFT from perspective of mesoscopic fracture morphology. First, notched semi-circle bend (NSCB) and short-core-in-compression (SCC) samples of granite were prepared for dynamic mode I and mode II fracture tests. Then, the DFT values of NSCB and SCC specimens at various loading rates were calculated and analyzed. After that, mesoscopic morphologies of failure surfaces of NSCB and SCC specimens under various loading rates were obtained by scanning electron microscope (SEM). The fracture morphology features of specimens were quantitatively characterized by a method combining deep learning and SEM images. The analytical results suggested that as loading rates rose, the increase in the percentage of mesoscopic fracture morphology caused by shear stress (MFM-S) on the fractured surface was the primary reason for the increase of DFT. When dynamic loading varied from 40 to 120 GPa m<sup>1/2</sup> s<sup>−1</sup>, there was a linear relationship between the DFT and the proportion of MFM-S. Additionally, with an increasing loading rate, the proportion of MFM-S on the fracture surface of NSCB specimens varied slightly more, which can explain why the dependence of DFT on loading rate in NSCB specimens was somewhat more obvious than in SCC specimens.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320432","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

Investigation of mechanical and ultrasonic properties of sandstone with different flaws characteristics under triaxial stress 不同缺陷特征砂岩在三轴应力下的力学和超声波特性研究

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-20 DOI: 10.1016/j.tafmec.2024.104689

{"title":"Investigation of mechanical and ultrasonic properties of sandstone with different flaws characteristics under triaxial stress","authors":"","doi":"10.1016/j.tafmec.2024.104689","DOIUrl":"10.1016/j.tafmec.2024.104689","url":null,"abstract":"<div><div>This study investigates the impact of flaw angle and length on the mechanical properties and ultrasonic wave velocity of sandstone under triaxial stress. Sandstone specimens with different flaw angles (0°, 30°, 60°, 90°) and varying flaw lengths (10 mm, 15 mm, 20 mm, 25 mm) underwent comprehensive examination through conventional triaxial compression tests and ultrasonic monitoring systems. The experimental results indicate that flaw angle and length significantly affect the sandstone’s mechanical properties and ultrasonic velocity. As the flaw angle increases, both the peak stress and elastic modulus of sandstone demonstrate an upward trend. Conversely, increasing flaw length diminishes the sandstone’s mechanical strength and structural integrity. Particularly noteworthy is the observation that when the flaw length exceeds 20 mm, the unstable expansion of cracks significantly escalates, resulting in sandstone fracture at lower stress levels. The variation of longitudinal wave velocity reflected the failure process and crack evolution characteristics of sandstone. The wave velocity initially shows a temporary increase followed by a continuous decrease, with the turning point occurring near the crack closure stress. In contrast, the evolution of crack width is observed to follow the opposite pattern. This study provides new insights into the impact of flaw characteristics on the mechanical and ultrasonic properties of sandstone, offering valuable guidance for geological engineering design, rock stability assessment, and coal mining operations.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311605","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

Study on the characteristics of CO2 fracturing rock damage based on fractal theory 基于分形理论的二氧化碳压裂岩石损伤特征研究

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-20 DOI: 10.1016/j.tafmec.2024.104691

{"title":"Study on the characteristics of CO2 fracturing rock damage based on fractal theory","authors":"","doi":"10.1016/j.tafmec.2024.104691","DOIUrl":"10.1016/j.tafmec.2024.104691","url":null,"abstract":"<div><div>CO<sub>2</sub> fracturing is emerging as a carbon–neutral technology for underground excavation. Traditional studies on structural stability during excavation have largely focused on the vibration characteristics of rocks. However, the inherent damage in rock layers during CO<sub>2</sub> fracturing poses significant challenges for understanding damage mechanisms under complex multi-field coupling. This study introduces a novel approach for calculating rock damage induced by CO<sub>2</sub> fracturing.We developed a physical model of CO<sub>2</sub> fracturing and applied a “two-stage effect” division method, creating a staged damage calculation model based on fractal damage mechanics theory. Experiments were conducted under combined dynamic and static loads to evaluate rock damage. A two-factor Analysis of Variance (ANOVA) was used to assess the significance of dynamic and static effects on the extent of rock damage.The findings revealed that static loads guide crack propagation direction, reducing the angle between the crack and vertical axis, while initial CO<sub>2</sub> dynamic load pressure strongly influences crack patterns, with higher pressures resulting in more fractures. The extent of rock damage observed ranged from 0.680 to 0.845. Although dynamic loads showed no significant impact, static loads exhibited a notable effect, as indicated by a P-value approaching 0.01. This study’s fractal-damage calculation model provides a valuable tool for addressing stability concerns in structures affected by CO<sub>2</sub> fracturing.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311697","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 closed form expression of stress intensity factor for an arbitrarily shaped planar crack in 3-D under tensile loading 拉伸荷载下任意形状平面裂缝的三维应力强度因子闭式表达式

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-19 DOI: 10.1016/j.tafmec.2024.104686

{"title":"A closed form expression of stress intensity factor for an arbitrarily shaped planar crack in 3-D under tensile loading","authors":"","doi":"10.1016/j.tafmec.2024.104686","DOIUrl":"10.1016/j.tafmec.2024.104686","url":null,"abstract":"<div><div>A closed-form equation was developed in this work to quantify the stress intensity factor (SIF) along an arbitrarily shaped planar crack under mode-I loading by substituting the ellipse-related parameters in Irwin’s solution with geometry-related parameters <span><math><msub><mi>f</mi><mi>i</mi></msub></math></span> of the crack. This allowed incorporation of the local crack curvature effect on SIF at each discrete point along the crack front and its relative weighted contribution to SIF of the neighboring crack point <em>i</em>, where either stress concentration or shielding took place, into computation of the SIF distribution along the crack front. Good agreement was obtained between the <span><math><msub><mi>K</mi><mi>I</mi></msub></math></span> values derived in the current work and previous numerical simulation-based studies. The current method could capture the <span><math><msub><mi>K</mi><mi>I</mi></msub></math></span> distributions for surface and embedded cracks having the same shape, with their maximum values being consistent with Murakami’s <span><math><msqrt><mrow><mi>area</mi></mrow></msqrt></math></span> method. This solution of <span><math><msub><mi>K</mi><mi>I</mi></msub></math></span> allows for highly efficient calculation of <span><math><mrow><mi>Δ</mi><msub><mi>K</mi><mi>I</mi></msub></mrow></math></span> for quantification of the 3D growth behaviors of a fatigue crack with a complex shape, paving the way for studying the statistical nature of short fatigue crack growth.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528457","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

Research on the propagation characteristics of multiple cracks in steel bridge joints 钢桥接缝多裂缝扩展特征研究

IF 5 2区工程技术

Theoretical and Applied Fracture Mechanics Pub Date : 2024-09-19 DOI: 10.1016/j.tafmec.2024.104688

{"title":"Research on the propagation characteristics of multiple cracks in steel bridge joints","authors":"","doi":"10.1016/j.tafmec.2024.104688","DOIUrl":"10.1016/j.tafmec.2024.104688","url":null,"abstract":"<div><div>This study explores the morphological changes and interaction mechanisms of multiple crack propagations in steel bridge joints. Fatigue testing was conducted to determine the locations at which multiple cracks initiated and to obtain fatigue fracture surfaces with easily discernible crack propagation traces. Based on the theory of fracture mechanics, the propagation behavior of coplanar and out-of-plane cracks in joints was simulated using ABAQUS and FRANC3D joint simulation technology. The characteristics of the morphological changes were analyzed, and the interaction mechanism between different crack spacings was investigated to quantitatively characterize the relative positions at which cracks were enhanced or suppressed. The results showed that coplanar cracks exhibited different morphological trends and propagation rates in different stages of propagation. The shape of the crack front continuously changed, and the merging point that appeared during fusion rapidly expanded and evolved into a semi-elliptical crack. The fatigue life was more sensitive to the relative position of multiple cracks. In particular, the fusion of coplanar cracks significantly reduced the fatigue life, and the mutual suppression effect between heterogeneous cracks increased the fatigue life. When the ratio of coplanar crack spacing to crack length (<em>s</em>/2<em>c</em>) was less than 0.2, the crack fusion process significantly accelerated. In addition, when the <em>a</em><sub>2</sub>/<em>a</em><sub>1</sub> ratio of the crack propagation depth dropped below 0.5, the suppression effect was significant. Finally, by determining the spacing between multiple cracks, the method established this study can provide a reference for the design of fatigue resistance and joint optimization.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":null,"pages":null},"PeriodicalIF":5.0,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142311696","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