Engineering Fracture Mechanics最新文献

{"title":"A coupled experimental and discrete numerical study of mixed-mode fracture in rock-like materials","authors":"Jia-Le Li ,&nbsp;Gao-Feng Zhao ,&nbsp;Xin-Dong Wei ,&nbsp;Fuxin Rui ,&nbsp;Zhe Li ,&nbsp;Qin Li ,&nbsp;Kostas Senetakis","doi":"10.1016/j.engfracmech.2025.111195","DOIUrl":"10.1016/j.engfracmech.2025.111195","url":null,"abstract":"<div><div>In rock-like materials, fractures often occur under complex stresses involving both shear (mode II) and tensile (mode I) stresses. Traditional mixed-mode fracture models typically incorporate elements related to shear components. However, recent research has indicated that a model omitting the shear component might effectively describe mixed-mode fractures, although further in-depth investigations are necessary. This study employs a discrete numerical approach to investigate mixed-mode fracture mechanisms in rock-like materials, with a specific focus on tension–compression interactions at the mesoscale, not involving shear-related terms. This approach is enhanced by integrating a reinforced or weakening compression response within a cohesive zone-like model, which allows for a more accurate representation of complex stress responses in these materials. The comparative study shows that the model can achieve high agreement with the experimental results in mixed-mode fracture tests, including load–displacement behavior, crack opening displacement (COD) determined by discrete digital image correlation (DDIC), and fracture pattern. Later, the fracture mechanism and cracking behavior are analyzed numerically, and the correctness and feasibility are verified through several complex fracture scenarios, involving tension-shear and compression-shear. The numerical model, which correlates macro-level fiber stress tensors with traditional strength criteria for bond fracturing, offers a promising numerical tool for addressing various fracture issues, particularly in complex three-dimensional scenarios.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"323 ","pages":"Article 111195"},"PeriodicalIF":4.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912256","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}

{"title":"Evolution of the breakdown pressure and fracture induced by water-/liquid CO2-based indirect fracturing","authors":"Dijie Zhu ,&nbsp;Zike Gu ,&nbsp;Fengqi Guo","doi":"10.1016/j.engfracmech.2025.111190","DOIUrl":"10.1016/j.engfracmech.2025.111190","url":null,"abstract":"<div><div>Indirect fracturing represents an innovative approach for the extraction of coalbed methane (CBM) from broken-soft coal seams, with the primary objective being the penetration of fractures and the generation of a complex fracture network with high conductivity within the coal. To investigate the impact of borehole-interface distances on breakdown pressure and fracture characteristics, as well as the suitability of liquid CO₂ (L-CO₂) for CBM extraction via indirect fracturing, a series of fracturing experiments utilizing water and L-CO₂ on coal-rock blocks were conducted. The findings indicate that reducing the borehole-interface distance can lower the breakdown pressure and acoustic emission (AE) energy, while enhancing the complexity and roughness of fractures in coal; however, it may also impede fracture penetration. In comparison to water-based fracturing, L-CO₂-based fracturing significantly decreases the breakdown pressure and AE energy, resulting in a greater number of rougher fractures in coal. Utilizing fracture mechanics theory and the physicochemical properties of fluids, the mechanisms by which borehole-interface distance and L-CO₂ influence breakdown pressure and fracture characteristics were thoroughly analyzed. This study offers theoretical insights for CBM extraction employing water- and L-CO₂-based indirect fracturing techniques.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111190"},"PeriodicalIF":4.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908063","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}

{"title":"Fracture toughness evaluation of shale based on machine learning and micromechanical approach","authors":"Lei Han ,&nbsp;Xian Shi ,&nbsp;Hongjian Ni ,&nbsp;Shu Jiang ,&nbsp;Mingguang Che ,&nbsp;Fengtao Qu","doi":"10.1016/j.engfracmech.2025.111194","DOIUrl":"10.1016/j.engfracmech.2025.111194","url":null,"abstract":"<div><div>The fracture toughness of shale is of great significance for quantitatively evaluating the fracturability of shale reservoirs. Therefore, machine learning and nanoindentation mechanics testing techniques are used to study rock mechanics’ micro fracture toughness characteristics and complete the scale upgrade. Statistical nanoindentation and deep nanoindentation mechanical experiments (indentation morphology method) were conducted on rock samples from the Longmaxi Formation, and SEM images of indentation points were simultaneously collected. Based on the verification that the indentation range of the sample can represent the overall mechanical properties, machine learning methods were used to upgrade the scale modeling and conduct analysis and discussion. The results indicate that the fracture toughness based on the fracture length method is closer to Type I (tensile) fracture toughness, while the fracture toughness based on the energy method is closer to Type II (shear) fracture toughness, approximately three times that of Type I. Load strength and indentation depth are the main reasons for the difference in results between the two testing methods. The K-means dynamic homogeneous clustering machine learning method and deconvolution method can identify three physical phases: organic matter/clay, intermediate substances (composite phases), and hard minerals. The average errors between the obtained shale elastic modulus and hardness using machine learning algorithms and the deconvolution results are 3.70 % and 2.44 %, respectively. Compared to Gaussian deconvolution, the K-means clustering method can clarify the boundaries of individual physical clusters more clearly, making it easier to quantify the properties of clusters and evaluate the coupling relationship between physical quantities through two-dimensional and three-dimensional clustering. In addition, deconvolution methods can collaborate with K-means to determine initial cluster centers, further improving the accuracy of mechanical parameter interpretation for microscopic phases. The combination of statistical nanoindentation technology, deconvolution, machine learning, and other methods is of great significance for revealing the mechanical properties of heterogeneous shale at the micro nano scale and upgrading the scale, expanding the application of machine learning in the field of petroleum engineering.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"323 ","pages":"Article 111194"},"PeriodicalIF":4.7,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143937601","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}

{"title":"Longitudinal propagation mechanisms of multiple fractures in heterogeneous multi-lithology stacked reservoirs: A continuum-discontinuum simulation study","authors":"Guopeng Huang ,&nbsp;Minghui Li ,&nbsp;Jinqi Chu ,&nbsp;Fujian Zhou ,&nbsp;Guangbo Lu","doi":"10.1016/j.engfracmech.2025.111181","DOIUrl":"10.1016/j.engfracmech.2025.111181","url":null,"abstract":"<div><div>The longitudinal propagation of hydraulic fractures is significantly impeded by lithological heterogeneity and interfacial mechanical properties in multi-lithology stacked reservoirs. In this study, the hydraulic fracturing simulation method for heterogeneous multi-lithology stacked reservoirs is developed based on the continuous-discontinuous method (CDEM). First, the reliability of the model was verified based on the analytical solution. Then, the effects of different heterogeneity degree, vertical stress difference, interlayer stress difference, fluid viscosity and injection rate were investigated. The fracture height growth patterns, the evolution of injection pressure, and the stimulation degree were deep analyzed. The results show that the lithological heterogeneity degree and interface are primary factors governing fracture branching. Affected by the inter-cluster stress interference, the outer fractures are more likely to penetrate the lithologic interface than the inner fractures. As the heterogeneity degree increases, the fracture height growth is suppressed and the interface barrier effect becomes more pronounced. The vertical stress difference mainly controls the longitudinal tortuosity of the fractures. At a low stress contrast (2 MPa), stimulation is primarily driven by branch fracture development, whereas at a high stress contrast (10 MPa), it results from enhanced fracture aperture. When the interlayer stress differential exceeds 4 MPa, internal fractures remain confined within the sandstone layer. When the fluid viscosity increases from 5 mPa·s to 20 mPa·s, the reservoir stimulation degree can be increased by 35.3 %, and an optimal viscosity enhances both fracture height growth and complexity. This study provides critical insights for optimizing fracturing design parameters to achieve effective through-layer fracture propagation in heterogeneous stacked reservoirs.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111181"},"PeriodicalIF":4.7,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143881816","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}

{"title":"Correlation of temperature-dependent fracture behavior and thermo-mechanical behavior of a polypropylene pipe grade material under cyclic load","authors":"Jessica Hinczica ,&nbsp;Mario Messiha ,&nbsp;Jutta Geier ,&nbsp;Carina Maurer ,&nbsp;Gerald Pinter ,&nbsp;Florian Arbeiter","doi":"10.1016/j.engfracmech.2025.111182","DOIUrl":"10.1016/j.engfracmech.2025.111182","url":null,"abstract":"<div><div>The long-term performance of polypropylene (PP) is crucial for ensuring the reliability and safety of PP pressure and non-pressure pipes. One method that allows for an accelerated assessment of a material’s durability is the cyclic Cracked Round Bar (CRB) test, which was used to investigate the temperature-dependent fracture behavior of PP across a very broad temperature range of <em>T</em> = −10 °C to 95 °C including the glass transition of the material. Results are compared with tensile tests and dynamic mechanical analysis (DMA) to identify potential correlations between mechanical-, thermo-mechanical properties and the fracture behavior. Both failure mechanisms typical for pipe materials, the ductile Area I and quasi-brittle Area II as well as the transition knee point between these areas, could be examined at all investigated temperatures. Further analysis of crack opening displacement and hysteresis underlines this result. A key finding is the correlation between the applied stress intensity factor and corresponding cycle number of the knee point at a given temperature and the DMA-derived damping behavior tan <em>δ</em> of the material. These findings offer a novel approach to enhance the accuracy and efficiency of determining the fracture behavior across a wide temperature range. It highlights the role of temperature in fracture behavior determination and the hidden potential of the DMA method.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"323 ","pages":"Article 111182"},"PeriodicalIF":4.7,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917613","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}

{"title":"On the rock-cutting mechanism and vibration characteristics of TBM insert tooth cutter based on discrete element-dynamics coupling model","authors":"Zhang Mengqi ,&nbsp;Zhao Youquan ,&nbsp;Zhang Zhiyao ,&nbsp;Mo Jiliang ,&nbsp;Zhou Zhongrong","doi":"10.1016/j.engfracmech.2025.111191","DOIUrl":"10.1016/j.engfracmech.2025.111191","url":null,"abstract":"<div><div>Tunnel Boring Machines (TBM) are large-scale mechanical equipment used in underground engineering. As one of the key components of the TBM, the performance of the cutters significantly affects construction efficiency and cost. The insert tooth cutter is a high-performance tool with significant development potential, yet studies on its mechanisms are relatively scarce. The correlation between the alloy tooth structure and rock breakage remains unclear, and it is uncertain whether the insert tooth cutter causes additional vibrations. Therefore, this study conducts an in-depth analysis of the rock-cutting process of spherical and wedge-shaped insert tooth cutters using a discrete element-dynamics coupling model that comprehensively considers cutter-rock contact, vibration, and rock fragmentation. The results are compared with the flat-top cutters and circle-top cutters commonly used in engineering, exploring the performance characteristics of the insert tooth cutter and potential directions for design improvement. The results of the study show that, compared to flat-top and circle-top cutters, the insert tooth cutter, due to its alloy teeth, greatly reduces the contact area with the rock at the same penetration depth, significantly lowering the cutting load and specific energy. Additionally, the presence of the alloy teeth affects the vibration impact pattern of the insert tooth cutter during the rock-cutting process and increases the vibration intensity caused by per unit load. As a result, under the same loading conditions, the insert tooth cutter may induce more intense vibrations. While leveraging the advantage of the lower rock-cutting load of the insert tooth cutter, the additional equipment maintenance and handling caused by its vibrations should also be considered. The results provide data support for cutter selection in practical engineering, offer scientific guidance for optimizing the insert tooth cutter, and lay theoretical foundation for improving construction efficiency and ensuring construction safety.</div><div>© 2017 Elsevier Inc. All rights reserved.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111191"},"PeriodicalIF":4.7,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891897","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}

{"title":"Dynamic disturbance damage effects on the evolutionary characteristics of energy dissipation and fatigue rupture precursor of sandstone","authors":"Xing Wang ,&nbsp;Xueyan Zhang ,&nbsp;Daoxue Yang ,&nbsp;Kui Zhao ,&nbsp;Bo Li ,&nbsp;Shanhu Ran ,&nbsp;Zheng Sun","doi":"10.1016/j.engfracmech.2025.111192","DOIUrl":"10.1016/j.engfracmech.2025.111192","url":null,"abstract":"<div><div>Frequent dynamic disturbances, such as earthquakes and blasting, typically induce varying degrees of dynamic damage in rock masses. Repeated excavation and other cyclic loads during engineering operations can further aggravate this dynamic damage. This study focuses on the issue of energy evolution and fatigue fracture in rocks under cyclic loads caused by dynamic disturbance damage. The Hopkinson Pressure Bar (SHPB) was used to conduct cyclic dynamic impact tests on sandstone to quantitatively analyze the relationship between the number of impact cycles and dynamic disturbance damage. In addition, graded cyclic loading and unloading tests were performed on rock specimens affected by various dynamic disturbances in conjunction with the acoustic emission monitoring system. The ratio of total strain energy to elastic strain energy during cyclic loading and unloading was used to assess the cumulative damage degree of these rock specimens. In the presence of dynamic perturbation damage during cyclic loading and unloading, the cracking evolution characteristics of sandstone. The precursor characteristics of fatigue mechanical damage were simultaneously characterized using the laws of characteristic parameters of acoustic emission (AE) signals. The findings show that the sandstone specimens’ dynamic disturbance damage increases with the number of cycle hits, and that after more than six impacts, the growth rate sharply declines. The strength, wave velocity and porosity of specimens are significantly affected. The presence of different dynamic damages in the specimens did not significantly affect the relationship between total energy density, elastic energy density, dissipated energy density and axial stress. The total strain energy is linearly correlated with the elastic strain energy and remains largely unaffected by dynamic disturbance-induced damage. During the initial stage of cyclic loading and unloading in specimens subjected to varying impact times, the RA and AF values exhibit a substantial increase, which indicates a marked rise in the number of tensile and shear microcracks. Furthermore, in the damage phase preceding specimen failure, the impacted specimens demonstrate a significantly higher number of high RA and AF acoustic emission signals compared to non-impacted specimens, as well as a considerably greater quantity of cracks generated than in non-impacted specimens. Meanwhile, during the cyclic loading and unloading process, the average frequency centroid of the AE signals decreases, and the number of low-frequency AE signals increases. This can be regarded as a precursor feature of specimen damage and failure under this loading condition.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111192"},"PeriodicalIF":4.7,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143903333","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}

{"title":"Modeling multiple crack propagation in the material point method by J-integral methods accounting for other cracks intersecting the J contour","authors":"John A. Nairn ,&nbsp;Yamina E. Aimene","doi":"10.1016/j.engfracmech.2025.111143","DOIUrl":"10.1016/j.engfracmech.2025.111143","url":null,"abstract":"<div><div>Numerical crack propagation modeling of multiple, explicit cracks requires methods that can resolve interacting, and potentially intersecting, cracks as well as methods to calculate crack-tip parameters with sufficient accuracy for predicting when and where cracks propagate. These problems were solved using the material point method (MPM). First, the MPM method for modeling a single explicit crack known as CRAMP method was extended to account for two interacting explicit cracks by tracking four instead of original two crack velocity fields needed to resolve one explicit crack. Second, crack propagation and propagation direction were found using crack-tip <span><math><mi>J</mi></math></span> integral with partitioning into mode I and mode II stress intensity factors. <span><math><mi>J</mi></math></span> calculations, however, must be augmented whenever other cracks intersect the <span><math><mi>J</mi></math></span> contour for a propagating crack. If the intersecting crack’s tip is inside the <span><math><mi>J</mi></math></span> contour, the contour must be adapted to avoid that tip. A robust <span><math><mi>J</mi></math></span> calculation algorithm with intersecting-crack corrections is provided. Several examples show the new corrections are accurate. Selected crack propagation examples show the new methods have sufficient accuracy for interacting crack propagation calculations without any need to remesh or highly refine crack-tip regions.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111143"},"PeriodicalIF":4.7,"publicationDate":"2025-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143907965","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}

{"title":"On plastic crack driving force in crystal-plasticity phase-field fracture model","authors":"Yucheng Shu ,&nbsp;Wenxuan Hu ,&nbsp;Yiqi Zhu,&nbsp;Min Yi","doi":"10.1016/j.engfracmech.2025.111140","DOIUrl":"10.1016/j.engfracmech.2025.111140","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Coupled crystal-plasticity phase-field (CPPF) fracture models could potentially forecast short crack propagation, but there is no consensus on the crack driving force (CDF) from the plastic contribution among existing CPPF fracture models. Herein, we systematically investigate CPPF fracture models with four types of plastic CDFs and identify these models’ capability in simulating crack propagation in single crystal. These models comprehensively account for various CDFs arising from plastic dissipated energy (&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,diss&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;), plastic locking energy (&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,lock&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;), defect energy (&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,defect&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;), and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,diss&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; combined with critical energy release rate (&lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;c&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt;) reduction. The objective is to assess the rationality and distinctions among different CPPF fracture models in simulating the fracture of single crystal and analyze the change of plastic strain and plastic energy during crack propagation. It is found that in a single-edge notched face-centered cubic single-crystal copper subjected to tension along [001] direction, the CPPF fracture models with CDF from &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,diss&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,defect&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; can only reproduce the brittle-like type-I cracking with crack path perpendicular to [001] axis. This is attributed to that both &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,diss&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,defect&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; are much lower than elastic energy (&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;e&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;) and thus &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;e&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; dominates the cracking behavior. In contrast, CPPF fracture models with CDF from &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,lock&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; and &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,diss&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; with &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;G&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;c&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; reduction can replicate the ductile cracking with crack path along the slip direction (45 ° to [001] axis), agreeing with experimental observations. The model with &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;ψ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mtext&gt;p,lock&lt;/mtext&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; is further demonstrated rational in predicting both brittle and ductile fracture. In addition, the","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111140"},"PeriodicalIF":4.7,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886735","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}

{"title":"Study on ductile fracture model considering pre-strain and its application during incremental forming for 2091 aluminum alloy","authors":"Zhe Jia ,&nbsp;Huanhuan Dou ,&nbsp;Yang Liu ,&nbsp;Zhiwu Wang ,&nbsp;Hengming Zhang ,&nbsp;Tianyang Yue ,&nbsp;Lei Mu","doi":"10.1016/j.engfracmech.2025.111177","DOIUrl":"10.1016/j.engfracmech.2025.111177","url":null,"abstract":"<div><div>An uncoupled ductile fracture model, considering the influence of pre-strain, is used to predict cracking behavior for 2091 aluminum alloy during incremental forming. Firstly, uniaxial tension tests were performed at pre-strains of 6%, 8%, and 10% to obtain the basic mechanical properties of material. Five specimens, covering different stress states, were employed to conduct ductile fracture experiments. A hybrid numerical-experimental method was utilized to calibrate parameters of ductile fracture model. The results indicated that as the pre-strain increased from 0% to 8%, the average fracture strain of specimens under varying stress states decreased by 26.71%. Then, the original ductile fracture model was then enhanced by incorporating the effect of pre-strain through regression analysis, improving its accuracy in describing ductile fracture behavior under varying loading conditions. Finally, an incremental forming test was performed and simulated in order to validate the applicability of the modified ductile fracture model. Compared to the experimental results, the model predicted the forming height with an error of 0.12%. It demonstrate that the occurrence of crack failure can be accurately predicted by the proposed ductile fracture model during incremental forming process.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"322 ","pages":"Article 111177"},"PeriodicalIF":4.7,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143881815","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}