Engineering Fracture Mechanics最新文献_第6页

A hybrid method of coupling phase field model and linear elastic model to simulate fracture using cell-based smooth finite element method and finite element method

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110750

Yuanfeng Yu , Chi Hou , Timon Rabczuk , Meiying Zhao

The phase field model’s computational efficiency is increased in this work by connecting it to the linear elastic model. Firstly, the whole region is split up into many subregions, and each region’s mechanical characteristics determine which matching solution scheme to use. The linear elastic model lowers computational costs by allowing the use of rougher mesh and solving problems in non-crack areas. Only crack patterns inside the fracture propagation region may be predicted using the phase field model. Secondly, the model is implemented in a hybrid computational framework, which combines the computational efficiency of the cell-based smooth finite element technique (CSFEM) with the traditional finite element method (FEM). Lastly, illustrative instances are applied to verify the coupled model. The findings demonstrate that the energy and mechanical parameters for the coupled model and the pure phase field model coincide quite well. In addition to reducing computation time, the simulation findings of the coupled model are identical to those of the pure phase field model, and the fracture trajectories of the test samples are unaffected regardless of the failure modes.

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引用次数: 0

Comparative experimental investigation on shale fracture propagation induced by high-temperature water and carbon dioxide

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110727

Jiao Ge , Chuanjin Yao , Qi Zhang , Xingheng Huang , Tiankui Guo , Shenglai Guo

High-temperature convective heating is a promising in situ conversion method that has the potential to improve the productivity of oil and gas reservoirs substantially. Thermal fluid can efficiently fracture rocks and enhance the permeability of reservoirs. A self-developed in situ high-temperature convective thermal simulation experimental equipment was utilized to fracture shale in this research. The patterns of fracture propagation in shale fractured by high-temperature water and CO₂ were systematically investigated. The experimental results indicated that high-temperature convective heat may significantly decreased the fracture pressure and increased the complexity of fracture propagation. In comparison to conventional hydraulic fracturing, the fracture pressure of shale decreased by 50.75% with 450℃ water fracturing and by 62.23% with 450℃ CO₂ fracturing. The decrease in shale fracture pressure mainly resulted from the permeation of low viscosity fluid into minuscule pores or fractures, reducing the effective stress. Elevated temperature fluid induced the formation of many bending fractures, and the width of these fractures enlarged. As the temperature of the injected fluid rose, the intensity of thermal shock, the number of microcracks, and the severity of rock damage all increased. CO₂ fractured shale had more branch fractures and rough fracture surfaces than water. These characteristics facilitated the formation of complex fracture networks inside the shale. The fracture properties of thermal fluid fracturing shale were better understood through this work, which offered references for implementing in situ high-temperature convective thermal recovery in shale reservoirs.

{"title":"Comparative experimental investigation on shale fracture propagation induced by high-temperature water and carbon dioxide","authors":"Jiao Ge , Chuanjin Yao , Qi Zhang , Xingheng Huang , Tiankui Guo , Shenglai Guo","doi":"10.1016/j.engfracmech.2024.110727","DOIUrl":"10.1016/j.engfracmech.2024.110727","url":null,"abstract":"<div><div>High-temperature convective heating is a promising in situ conversion method that has the potential to improve the productivity of oil and gas reservoirs substantially. Thermal fluid can efficiently fracture rocks and enhance the permeability of reservoirs. A self-developed in situ high-temperature convective thermal simulation experimental equipment was utilized to fracture shale in this research. The patterns of fracture propagation in shale fractured by high-temperature water and CO<sub>2</sub> were systematically investigated. The experimental results indicated that high-temperature convective heat may significantly decreased the fracture pressure and increased the complexity of fracture propagation. In comparison to conventional hydraulic fracturing, the fracture pressure of shale decreased by 50.75% with 450℃ water fracturing and by 62.23% with 450℃ CO<sub>2</sub> fracturing. The decrease in shale fracture pressure mainly resulted from the permeation of low viscosity fluid into minuscule pores or fractures, reducing the effective stress. Elevated temperature fluid induced the formation of many bending fractures, and the width of these fractures enlarged. As the temperature of the injected fluid rose, the intensity of thermal shock, the number of microcracks, and the severity of rock damage all increased. CO<sub>2</sub> fractured shale had more branch fractures and rough fracture surfaces than water. These characteristics facilitated the formation of complex fracture networks inside the shale. The fracture properties of thermal fluid fracturing shale were better understood through this work, which offered references for implementing in situ high-temperature convective thermal recovery in shale reservoirs.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110727"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166098","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

Surgical face masks as reinforcement to improve the tensile mode fracture toughness of reinforced concrete under three-point bending tests

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110741

Hadi Haeri , Jinwei Fu , Vahab Sarfarazi , Soheil Abharian , Haleh rasekh , Mohammad Rezaei , Manoj Khandelwal

A set of experimental three-point bending tests and numerical simulations for using surgical masks as reinforcing layers in concrete samples were carried out. Different samples were prepared for analysis with changes in the number and position of the masks. The tensile strength of concrete was measured at 2.1 MPa, while that of face musk was 4.3 MPa. In these samples, fracture patterns, maximum load, fracture toughness of state I, fracture energy, and external work at the point of peak load were investigated based on the theory of fracture mechanics. The fracture procedure of specimens without face masks evolves quicker than the specimens with face masks. When the face mask was situated upper the notch, the fracture toughness increased rapidly by increasing the face mask number. When one face mask was situated upper the notch, the fracture toughness decreases by increasing the distance between the face mask and the lower boundary. When the face mask goes through the notch, the fracture toughness has the maximum value. It decreases by increasing the distance between the face mask and the lower boundary. When two face masks exist in the model, the fracture toughness decreases by increasing the distance between the face mask and the lower boundary. In addition, the external work decreases by increasing the distance between two face masks.

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引用次数: 0

Assessing the effects of loading rate on fracture toughness of AISI 1020 and API 5L X80 steels with hydrogen charging: experimental and numeric simulation study

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110771

Hantong Wang , Ci Zhang , Haonan Ma , Zhi Tong , Yibai Huang , Ying Jin , Cheng Su , Wenyue Zheng

<div><div>This study focuses on the effect of hydrogen on fracture toughness of AISI 1020 and API 5L X80 steels using experimental measurement technique and numeric simulation. Hydrogen was introduced into Single Edge Notch Bend (SENB) specimens through in-situ electrochemical charging techniques. The study varied the loading rates (K̇) and observed a significant reduction in the fracture toughness of both types of steels with hydrogen presence, worsening as loading rates decreased. The findings illustrated that the current standards of hydrogen compatibility test, which specifies a loading rate that ranges from <span><math><mrow><mn>0.1</mn><mi>M</mi><mi>P</mi><mi>a</mi><msqrt><mi>m</mi></msqrt><mo>/</mo><mi>m</mi><mi>i</mi><mi>n</mi></mrow></math></span> to <span><math><mrow><mn>1</mn><mspace></mspace><mi>M</mi><mi>P</mi><mi>a</mi><msqrt><mi>m</mi></msqrt><mo>/</mo><mi>m</mi><mi>i</mi><mi>n</mi></mrow></math></span> in toughness tests, may produce non-conservative results by not fully capturing the degradation at lower loading rates (K̇ <＜<span><math><mn>0.1</mn><mspace></mspace><mi>M</mi><mi>P</mi><mi>a</mi><msqrt><mi>m</mi></msqrt><mo>/</mo><mi>m</mi><mi>i</mi><mi>n</mi></math></span>). The low-strength steel (AISI 1020) showed a fracture mode transition from the Hydrogen-Enhanced Localized Plasticity (HELP) to the Hydrogen-Enhanced Decohesion (HEDE) as the K̇ decreases. Nevertheless, the crack re-initiation sites are always found at the tips of pre-cracks, which coincide with the areas of a high local hydrogen concentration and a high plastic strain. In contrast, the crack initiation sites in X80 steel tend to shift from the regions with high-strain (i.e. near the crack front) to areas with high hydrostatic stress (some distance away from the crack front) as the K̇ decreases, although it is still a predominantly quasi-cleavage (QC) fracture mode.</div><div>Finite element analysis further revealed that the diffusion and trapping of hydrogen atoms are significantly influenced by the gradient of hydrostatic stress and increment of plastic strain in the crack front region. In AISI 1020 steel, the concentration of trapped hydrogen significantly exceeds that of diffusible lattice interstitial hydrogen; In this case, the trapped hydrogen predominately dictates the distribution profile of total hydrogen at all K̇ conditions, whereas in X80 steel, the relative dominance of diffusible and trapped hydrogen depends on the loading rate: at lower K̇, diffusible hydrogen concentration at lattice sites exceeds that of the trapped hydrogen and there is a dynamic equilibrium relationship between the hydrogen induced by hydrostatic stress and the hydrogen trapped by plastic strain; at higher K̇, the hydrogen in trap sites dominate the hydrogen distribution. The differences in hydrogen concentration distribution are linked with different crack nucleation behaviours of the two steels under different loading rates, as well corroborated by fractographic observa

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引用次数: 0

Fracture of multilayer soft materials

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110747

Kunqing Yu, Yijie Cai, Zheng Jia

In recent decades, soft materials such as hydrogels and elastomers have been rising and continuing to develop in engineering fields. Among them, layered stretchable structures composed of multilayer soft materials have attracted widespread attention due to their excellent mechanical properties and versatility. Notably, despite the rapid advancements in the design and functional development, there remains a scarcity of research on the fracture behavior of these multilayer soft materials. To address this largely unexplored issue, in this paper we study the fracture mechanics of multilayer soft materials. A theoretical framework is established to analyze the fracture modes of film-substrate structures composed of multiple layers of soft materials under tension. Then the proposed framework is applied to investigate the fracture of typical three-layered and four-layered soft structures with pre-crack in the films. The normalized driving force and critical stretches for different configurations of cracks are calculated. Furthermore, the failure phase diagrams for different film thickness are plotted. This work provides a theoretical basis for predicting the fracture of multilayer soft materials, thereby offering quantitative guidance for the design of soft layered structures with better fracture resistance.

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引用次数: 0

Advancements in cold extrusion anti-fatigue manufacturing technology for connecting holes

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110764

Nian Wan , Biao Zhao , Wenfeng Ding , Qiang He

Requirements for connection reliability, stability, and service of components in the design and manufacturing process for aeronautical equipment are progressively growing stricter. The utilization of cold extrusion technology significantly contributes to the improvement of hole strength in the anti-fatigue manufacturing process of perforated specimens. The assessment of part quality frequently depends on residual stress, representing the mechanical stress encountered by materials during machining processes. Understanding the underlying mechanism of extrusion-induced residual stress is equally crucial. This comprehensively study aims to analyze the influential factors in the generation of residual stress, with the objective of elucidating the multifaceted mechanism behind anti-fatigue processing. Firstly, a comprehensive analysis of the mechanisms and influential factors governing residual stress during extrusion is presented, followed by a concise overview of commonly employed detection techniques. Subsequently, the micro-deformation behavior of typical materials under various extrusion methods is investigated and a comprehensive analysis is conducted on their characteristics and application range. Finally, the gain of extrusion and the mechanism of anti-fatigue manufacturing technology are further elucidated from the perspectives of stress, plastic deformation, surface integrity, and fatigue life. This present research contributes to enhancing the understanding of residual stress in hole extrusion and accurately predicting their developmental trajectory.

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引用次数: 0

Analysis of sensitivity factors on CJB mechanical behavior from specimen scale to engineering scale

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110673

Bin Gong , Yongyi Wang , Xu Chen , Wencheng Song , Kaikai Wang , Jiang Yu

The mechanical behaviors of columnar jointed basalts (CJBs) are affected by various sensitivity factors and show significant cross-scale differences. Employing the representative models ranging from individual CJB specimens to tunnels, the sensitivity factors including joint mechanical characteristics, mesoscopic rock constitutive relations, and model boundaries are meticulously considered. Combined with digital image correlation, these models are rigorously tested against the meso-damage mechanics, statistical strength theory, and continuum mechanics. Subsequently, a comprehensive examination ensues, delving into the spectrum of influencing factors, fracture mechanisms, and sensitivity analyses of CJBs. Notably, it emerges that the mechanical anisotropy of CJB specimens is most susceptible to boundary condition, while joint mechanical property is more sensitive than mesoscopic rock constitutive relation. Furthermore, the specimen height-width ratio exhibits relative insensitivity, whereas the excavation stage is relatively sensitive for CJB tunnel. The proportional distance of subsidiary joint set manifests a lesser impact compared to the other parameters. Besides, from specimen scale to tunnel scale, the sensitive factor rankings on the mechanical behavior of related models are summarized. These achievements not only enhance our understanding of cross-scale CJB mechanics but also provide crucial knowledge for experimental setup, engineering design, and lifecycle management of CJB-involved projects.

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引用次数: 0

Energy storage characteristics and damage constitutive model of thermally treated granite: An experimental investigation

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110679

Jiexin Ma, Tubing Yin, You Wu, Wenxuan Guo, Yongjun Chen, Zheng Yang

With the development of deep Earth energy engineering in the 21st century, the challenges brought by high stress and high temperature will become increasingly frequent. In the development of deep geothermal resources, the constitutive relationship of high-temperature rock mechanics is a core issue faced by geothermal development projects. In this paper, investigates the static mechanical behavior and brittle ductile failure characteristics of granite under heat treatment at 25, 200, 400, 600, and 800 ℃ during uniaxial compression, based on the linear energy storage rule of high-temperature rock under uniaxial compression before peak strength, we propose an energy dissipation rule post-peak, leading to an energy evolution rule for the whole failure process of high-temperature rock. Based this, the stress–strain curve characteristics of the rock after reaching the rock peak were characterized for the first time. Then, establish the corresponding constitutive model. The calculation relationship of pre-peak strain energy as the independent variable is determined by uniaxial loading and unloading test, and the model parameters are calibrated. The calculation results can better reflect the brittleness characteristics of granite and the transition from brittleness to ductility with increasing temperature, solving the problems that all previous constitutive relationships cannot reflect the post peak curve of the rock failure. The peak strength and strain observed at various temperatures align well with our experimental findings, confirming the model’s validity presented in this article, which can provide theoretical guidance for practical geothermal engineering applications.

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引用次数: 0

Cone cracking and fragmentation of alumina plates under high-speed penetration: Experiments and modeling

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110733

J.C. Yuan , J.Y. Hua , Y.L. Bian , W.J. Zhang , Z.Y. Liu , Y. Cai , J.Y. Huang , S.N. Luo

Ballistic damage and fragmentation of alumina ceramic plates are investigated with ballistic impact experiments and numerical simulations. Ballistic impact tests are conducted with steel spherical projectiles (5 mm diameter) at 274–1040 m s⁻¹ using one- and two-stage gas guns along with high-speed photography. The postmortem targets are characterized with optical imaging, three-dimensional (3D) laser scanning and scanning electron microscopy. As the impact velocity increases, ceramic targets show damage modes as radial cracks (without cones), cone cracks, cone spallation, and cone fragmentation in sequence. The diameter, volume, and surface angles of the conical bullet holes (or ceramic cones) increase, while the height of ceramic cone decreases, with the increase of impact velocity. In the impact region, the shock compression-induc ed and tension-induced damage produce granular and coarse fragments, respectively, with the fragment size distribution following a power law. Numerical ballistic simulations are performed using the smooth particle hydrodynamics and finite element methods (SPH-FEM) along with the Johnson–Cook and Johnson–Holmquist constitutive models. The SPH-FEM fixed coupling model can capture the failure mechanisms and fragmentation characteristics of ceramic targets, including the 3D morphology evolution of ceramic cones. The angle deflection of the cone cracks is attributed to the stress wave interactions from the projectile and target free surfaces, altering the stress state at the crack tip and thus crack propagation direction.

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引用次数: 0

Research on the influence of axial deck media on damage and stress field distribution characteristics of glauconite

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110740

Yuanyuan You , Renshu Yang , Zhongwen Yue , Jinjing Zuo , Xinmin Ma , Chenxi Ding , Chenglong Xiao

The type of axial decking medium significantly influences the efficiency of rock blasting fragmentation, the distribution of the stress field, and the energy transmitted into the rock. This study conducted experiments on glauconite samples utilizing a passive confining pressure device outfitted with four distinct axial decking media charge structures to indicate the rock-breaking mechanism associated with various axial decking media. In conjunction with box counting dimension and fractal dimension theories, computer tomography (CT) scanning and 3D model reconstruction techniques are utilized to visualize the spatial distribution and morphology of explosion-induced cracks. This approach also facilitates a quantitative analysis of the rock damage incurred by the explosions. The results indicated that liquid (water) deck medium charges result in the most substantial rock damage, followed by solid (rock powder), solid (sand), and gas (air) deck medium charges, respectively. The maximum rock damage recorded with water deck medium charges is 0.826, whereas the minimum is 0.778 for air deck medium charges. Then, LS-DYNA numerical simulation software is employed to develop rock blasting models with varying deck media charges, capturing the dynamic evolution of rock damage. The numerical outcomes confirm the laboratory ones and illustrate how different decking media impact the distribution of the explosive stress field and energy transfer efficiency. When employing a liquid (water) axial decking medium, the rock demonstrates the greatest internal energy input and the swiftest rate of energy transfer, with the internal energy input being 1.12 times and 1.68 times that of solid and gas media, respectively. These insights offer valuable theoretical support for designing and optimizing axial decking charge structures in field applications.

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引用次数: 0