Pub Date : 2025-12-06DOI: 10.1016/j.engfracmech.2025.111769
P. Rose , M. Linke , D. Busquets
This study investigates the influence of layup configuration on the failure behavior of composite bonded joints. Experimental results from quasi-static tests reveal that specimens with a 0°-oriented ply in contact with the adhesive consistently achieve higher fracture loads and exhibit simpler failure mechanisms compared to 45° configuration, where the crack propagates into the adherends and shows complex damage progression. Numerical simulations using cohesive zone modeling are conducted to predict this behavior. A method is applied to ensure sufficient resolution of the cohesive zone, and the influence of mesh size on predictive accuracy is assessed. The results show that at least nine cohesive elements are required within the cohesive zone for convergence in fracture load and accurate damage progression. The presented modeling approach accurately predicts both crack paths and fracture loads, particularly for complex failure scenarios. However, limitations remain for adhesive-layer-only failure due to sensitivity to surface pre-treatment and associated parameter uncertainty. The findings highlight the need for layup-sensitive modeling strategies and mesh resolution when analyzing bonded composite structures.
{"title":"Experimental investigation & numerical modeling of the layup-specific damage behavior of composite bonded joints under mixed-mode loading","authors":"P. Rose , M. Linke , D. Busquets","doi":"10.1016/j.engfracmech.2025.111769","DOIUrl":"10.1016/j.engfracmech.2025.111769","url":null,"abstract":"<div><div>This study investigates the influence of layup configuration on the failure behavior of composite bonded joints. Experimental results from quasi-static tests reveal that specimens with a 0°-oriented ply in contact with the adhesive consistently achieve higher fracture loads and exhibit simpler failure mechanisms compared to 45° configuration, where the crack propagates into the adherends and shows complex damage progression. Numerical simulations using cohesive zone modeling are conducted to predict this behavior. A method is applied to ensure sufficient resolution of the cohesive zone, and the influence of mesh size on predictive accuracy is assessed. The results show that at least nine cohesive elements are required within the cohesive zone for convergence in fracture load and accurate damage progression. The presented modeling approach accurately predicts both crack paths and fracture loads, particularly for complex failure scenarios. However, limitations remain for adhesive-layer-only failure due to sensitivity to surface pre-treatment and associated parameter uncertainty. The findings highlight the need for layup-sensitive modeling strategies and mesh resolution when analyzing bonded composite structures.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111769"},"PeriodicalIF":5.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787415","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}
Pub Date : 2025-12-06DOI: 10.1016/j.engfracmech.2025.111767
Roshan Philip Saji , Panos Pantidis , Mostafa E. Mobasher
Accurate prediction of damage and fracture evolution is critical for the safe design and preventive maintenance of engineering structures, however existing computational methods face significant limitations. On one hand, discrete damage and phase-field models are often computationally prohibitive for real world applications and they are less generalizable across different material classes. On the other hand, conventional gradient damage models based on phenomenological laws, though computationally efficient, suffer from unrealistic widening of the damage band as damage progresses. This paper presents a modified non-local gradient damage model (MNLD) that overcomes these shortcomings by introducing changes to the stress degradation function and forcing term in the Helmholtz free energy expression. These two modifications ensure that as damage approaches its maximum value, both the thermodynamic damage driving force for damage vanishes and the evolution of the forcing term decays. Consequently, the damage band retains a non-growing constant width throughout its evolution. The proposed approach builds on insights gained from two intermediate models, which addressed the necessary conditions separately before integrating them into a unified formulation. Numerical validation is performed on several 1D, 2D and 3D benchmark problems, demonstrating that the proposed model can reliably produce fixed-width damage bands. The proposed approach can be implemented within existing gradient damage-based finite element frameworks with minimal implementation changes. The results highlight the potential of this approach to resolve the decades-long challenge of spurious widening in gradient damage models, offering an effective and practical solution for engineering applications.
{"title":"Modified non-local damage model: Resolving spurious damage evolution","authors":"Roshan Philip Saji , Panos Pantidis , Mostafa E. Mobasher","doi":"10.1016/j.engfracmech.2025.111767","DOIUrl":"10.1016/j.engfracmech.2025.111767","url":null,"abstract":"<div><div>Accurate prediction of damage and fracture evolution is critical for the safe design and preventive maintenance of engineering structures, however existing computational methods face significant limitations. On one hand, discrete damage and phase-field models are often computationally prohibitive for real world applications and they are less generalizable across different material classes. On the other hand, conventional gradient damage models based on phenomenological laws, though computationally efficient, suffer from unrealistic widening of the damage band as damage progresses. This paper presents a modified non-local gradient damage model (MNLD) that overcomes these shortcomings by introducing changes to the stress degradation function and forcing term in the Helmholtz free energy expression. These two modifications ensure that as damage approaches its maximum value, both the thermodynamic damage driving force for damage vanishes and the evolution of the forcing term decays. Consequently, the damage band retains a non-growing constant width throughout its evolution. The proposed approach builds on insights gained from two intermediate models, which addressed the necessary conditions separately before integrating them into a unified formulation. Numerical validation is performed on several 1D, 2D and 3D benchmark problems, demonstrating that the proposed model can reliably produce fixed-width damage bands. The proposed approach can be implemented within existing gradient damage-based finite element frameworks with minimal implementation changes. The results highlight the potential of this approach to resolve the decades-long challenge of spurious widening in gradient damage models, offering an effective and practical solution for engineering applications.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111767"},"PeriodicalIF":5.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787458","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}
Pub Date : 2025-12-06DOI: 10.1016/j.engfracmech.2025.111771
Mohsen Rajab Doost Khoshdel, Ali Fakhimi
A mechanistic understanding of rock chipping is critical for enhancing drilling efficiency and minimizing equipment wear. This study develops a higher-order finite-discrete element model with integrated elastic–plastic-fracture-erosion behavior to investigate chip formation across varying depths of cut. The numerical simulations identified tensile fracture as the dominant failure mode initiating chipping. A modified size effect law (SEL) is proposed to capture depth-dependent behavior. Beyond mere trend fitting, the proposed SEL enables slope-based identification of regime boundaries – ductile to fragmentation and fragmentation to brittle – via log–log analysis of specific energy versus depth. This framework offers an alternative to threshold-based methods and demonstrates improved predictive performance over Bažant’s SEL, with higher adjusted R2 and agreement with published data. By synthesizing the simulation results, the modified SEL framework, and the experimental data from literature, this study advances the understanding of fracture evolution and regime transitions in rock cutting.
{"title":"Higher-order FDEM modeling and size effect law for specific energy estimation in free rock cutting using a chisel pick","authors":"Mohsen Rajab Doost Khoshdel, Ali Fakhimi","doi":"10.1016/j.engfracmech.2025.111771","DOIUrl":"10.1016/j.engfracmech.2025.111771","url":null,"abstract":"<div><div>A mechanistic understanding of rock chipping is critical for enhancing drilling efficiency and minimizing equipment wear. This study develops a higher-order finite-discrete element model with integrated elastic–plastic-fracture-erosion behavior to investigate chip formation across varying depths of cut. The numerical simulations identified tensile fracture as the dominant failure mode initiating chipping. A modified size effect law (SEL) is proposed to capture depth-dependent behavior. Beyond mere trend fitting, the proposed SEL enables slope-based identification of regime boundaries – ductile to fragmentation and fragmentation to brittle – via log–log analysis of specific energy versus depth. This framework offers an alternative to threshold-based methods and demonstrates improved predictive performance over Bažant’s SEL, with higher adjusted R<sup>2</sup> and agreement with published data. By synthesizing the simulation results, the modified SEL framework, and the experimental data from literature, this study advances the understanding of fracture evolution and regime transitions in rock cutting.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111771"},"PeriodicalIF":5.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734406","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}
Pub Date : 2025-12-06DOI: 10.1016/j.engfracmech.2025.111777
Yu-Yi Ye , José Gonilha , Nuno Silvestre , João R. Correia
This paper presents an experimental and numerical study on the transverse tensile (Mode I) translaminar fracture behavior of pultruded glass fiber-reinforced polymer (GFRP) materials. First, wide compact tension (WCT) tests were conducted to investigate the effects of specimen length and fiber layup configuration. Failure modes, load–displacement curves and crack growth resistance curves (i.e., R-curves) are presented and analyzed. Some test results were influenced by compression damage at the free end of the specimens (end effect). To minimize its impact on the tensile fracture toughness and enable a more accurate assessment, a criterion is proposed to exclude data affected by this phenomenon. Alongside the experiments, advanced finite element (FE) models incorporating the Hashin failure criteria together with fracture toughness-based bilinear or linear-exponential damage evolution laws were developed to simulate the fracture behavior. The results indicate that pultruded GFRP materials exhibit quasi-brittle Mode I fracture behavior. Longer specimens exhibit a longer crack propagation process, and their corresponding R-curves effectively capture the full crack growth behavior, characterized by a distinct plateau region. In the cases studied, specimen length has a negligible effect on the material’s fracture toughness, but data affected by the end effect needs to be excluded (e.g., following the aforementioned criterion). A clear exponential relationship was also observed between fracture toughness and transverse tensile strength based on the available experimental data. In addition, both damage evolution laws reasonably capture the overall fracture behavior of pultruded GFRP materials, but the bilinear law provides more accurate predictions of ultimate loads.
{"title":"Effects of specimen length and fiber layup on transverse tensile fracture behavior of pultruded GFRP materials","authors":"Yu-Yi Ye , José Gonilha , Nuno Silvestre , João R. Correia","doi":"10.1016/j.engfracmech.2025.111777","DOIUrl":"10.1016/j.engfracmech.2025.111777","url":null,"abstract":"<div><div>This paper presents an experimental and numerical study on the transverse tensile (Mode<!--> <!-->I) translaminar fracture behavior of pultruded glass fiber-reinforced polymer (GFRP) materials. First, wide compact tension (WCT) tests were conducted to investigate the effects of specimen length and fiber layup configuration. Failure modes, load–displacement curves and crack growth resistance curves (i.e., R-curves) are presented and analyzed. Some test results were influenced by compression damage at the free end of the specimens (end effect). To minimize its impact on the tensile fracture toughness and enable a more accurate assessment, a criterion is proposed to exclude data affected by this phenomenon. Alongside the experiments, advanced finite element (FE) models incorporating the Hashin failure criteria together with fracture toughness-based bilinear or linear-exponential damage evolution laws were developed to simulate the fracture behavior. The results indicate that pultruded GFRP materials exhibit quasi-brittle Mode I fracture behavior. Longer specimens exhibit a longer crack propagation process, and their corresponding R-curves effectively capture the full crack growth behavior, characterized by a distinct plateau region. In the cases studied, specimen length has a negligible effect on the material’s fracture toughness, but data affected by the end effect needs to be excluded (e.g., following the aforementioned criterion). A clear exponential relationship was also observed between fracture toughness and transverse tensile strength based on the available experimental data. In addition, both damage evolution laws reasonably capture the overall fracture behavior of pultruded GFRP materials, but the bilinear law provides more accurate predictions of ultimate loads.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111777"},"PeriodicalIF":5.3,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787412","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}
Pub Date : 2025-12-05DOI: 10.1016/j.engfracmech.2025.111785
Yi Shen , Lanhao Shen , Tianbao Ma , Jianqiao Li
Aluminum alloys are typical lightweight metallic material, and their fracture behavior has attracted significant attention in the automotive and aerospace industries. In our investigation, a stress-state-dependent void nucleation strain was derived based on the maximum principal stress nucleation criterion and the Johnson-Cook (JC) constitutive model. Moreover, a improved physical damage model incorporating stress-state effects was established based on it. Its parameters were fitted using the void results in the ”strain freezing” experiments. Subsequently, the dynamic fracture behaviors of 5052 and 2024 aluminum alloys under different loading stress states (uniaxial tensile, tensile-shear mixed plane strain state, plane strain states with high stress triaxiality, and pure shear state) were investigated using Split Hopkinson Pressure Bar (SHPB). The improved physical damage model and four widely used traditional damage models were applied to numerically calculate the dynamic fracture behaviors for these cases. The new damage model successfully captured the macroscopic fracture morphologies, force–displacement curves, fracture strains (maximum error of −11.64%), and microscopic void ellipticity on fracture surfaces (maximum error of 13.08%) under different stress states of two aluminum alloys. Compared to traditional damage models, the new damage model not only had clear physical significance, but also exhibited higher predictive accuracy in fracture strain (average errors are 3.59% and 4.87% for 5052 and 2024 aluminum alloys). Moreover, the fracture initiation and propagation under tensile-dominated or shear-dominated loading were insensitive to the ductility for aluminum alloy. However, their fracture initiation and propagation exhibited notable differences under tensile-shear mixed loading.
{"title":"An improved physical damage model incorporating stress state effect for aluminum alloys","authors":"Yi Shen , Lanhao Shen , Tianbao Ma , Jianqiao Li","doi":"10.1016/j.engfracmech.2025.111785","DOIUrl":"10.1016/j.engfracmech.2025.111785","url":null,"abstract":"<div><div>Aluminum alloys are typical lightweight metallic material, and their fracture behavior has attracted significant attention in the automotive and aerospace industries. In our investigation, a stress-state-dependent void nucleation strain was derived based on the maximum principal stress nucleation criterion and the Johnson-Cook (JC) constitutive model. Moreover, a improved physical damage model incorporating stress-state effects was established based on it. Its parameters were fitted using the void results in the ”strain freezing” experiments. Subsequently, the dynamic fracture behaviors of 5052 and 2024 aluminum alloys under different loading stress states (uniaxial tensile, tensile-shear mixed plane strain state, plane strain states with high stress triaxiality, and pure shear state) were investigated using Split Hopkinson Pressure Bar (SHPB). The improved physical damage model and four widely used traditional damage models were applied to numerically calculate the dynamic fracture behaviors for these cases. The new damage model successfully captured the macroscopic fracture morphologies, force–displacement curves, fracture strains (maximum error of −11.64%), and microscopic void ellipticity on fracture surfaces (maximum error of 13.08%) under different stress states of two aluminum alloys. Compared to traditional damage models, the new damage model not only had clear physical significance, but also exhibited higher predictive accuracy in fracture strain (average errors are 3.59% and 4.87% for 5052 and 2024 aluminum alloys). Moreover, the fracture initiation and propagation under tensile-dominated or shear-dominated loading were insensitive to the ductility for aluminum alloy. However, their fracture initiation and propagation exhibited notable differences under tensile-shear mixed loading.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111785"},"PeriodicalIF":5.3,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683233","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}
Pub Date : 2025-12-03DOI: 10.1016/j.engfracmech.2025.111774
Bin Xu , Tao Xu , Abedulgader Baktheer , Xiaocong Lan , Michael J. Heap , David Amitrano , Ben Liu , Fadi Aldakheel
The phase field method (PFM) enables natural crack initiation and complex propagation by minimizing the system’s potential energy, eliminating the need for predefined failure criteria. While advantageous, this energy-driven approach can be limiting in scenarios where specific fracture criteria or control over crack direction and timing are essential, particularly in heterogeneous materials or those exhibiting tension–compression asymmetry. To overcome these limitations, we propose a dual-phase field model incorporating material heterogeneity and distinct evolution equations for mode-I and mode-II fractures. A directional weighting parameter is introduced to calibrate shear crack paths, allowing for controlled crack directionality from an energetic standpoint. Simulation results reveal that shear crack inclination increases as the weight parameter decreases, highlighting a strong correlation between this parameter and crack trajectory. The stress–strain response shows brittle behavior, with more pronounced softening and a shift toward ductile characteristics as the weight parameter increases. Material heterogeneity significantly influences both crack patterns and strength: weak zones foster localized, symmetric fractures, whereas strong zones produce more complex, asymmetric failures. Increased heterogeneity leads to irregular crack paths, lower peak strength, and reduced structural stability. Overall, the proposed model enhances predictive accuracy and flexibility in simulating mixed-mode fracture in heterogeneous geomaterials, offering valuable insights for engineering applications such as slope stability assessment and fracture risk mitigation.
{"title":"An energy-based dual phase-field model for shear cracking patterns in heterogeneous geomaterials","authors":"Bin Xu , Tao Xu , Abedulgader Baktheer , Xiaocong Lan , Michael J. Heap , David Amitrano , Ben Liu , Fadi Aldakheel","doi":"10.1016/j.engfracmech.2025.111774","DOIUrl":"10.1016/j.engfracmech.2025.111774","url":null,"abstract":"<div><div>The phase field method (PFM) enables natural crack initiation and complex propagation by minimizing the system’s potential energy, eliminating the need for predefined failure criteria. While advantageous, this energy-driven approach can be limiting in scenarios where specific fracture criteria or control over crack direction and timing are essential, particularly in heterogeneous materials or those exhibiting tension–compression asymmetry. To overcome these limitations, we propose a dual-phase field model incorporating material heterogeneity and distinct evolution equations for mode-I and mode-II fractures. A directional weighting parameter is introduced to calibrate shear crack paths, allowing for controlled crack directionality from an energetic standpoint. Simulation results reveal that shear crack inclination increases as the weight parameter decreases, highlighting a strong correlation between this parameter and crack trajectory. The stress–strain response shows brittle behavior, with more pronounced softening and a shift toward ductile characteristics as the weight parameter increases. Material heterogeneity significantly influences both crack patterns and strength: weak zones foster localized, symmetric fractures, whereas strong zones produce more complex, asymmetric failures. Increased heterogeneity leads to irregular crack paths, lower peak strength, and reduced structural stability. Overall, the proposed model enhances predictive accuracy and flexibility in simulating mixed-mode fracture in heterogeneous geomaterials, offering valuable insights for engineering applications such as slope stability assessment and fracture risk mitigation.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111774"},"PeriodicalIF":5.3,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683169","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}
Fracture and damage mechanics have evolved remarkably from simple, yet useful Linear Elastic Fracture Mechanics (LEFM) to relatively modern techniques such as Cohesive Zone Model (CZM) and phase-field approaches. The advent of computational power allowed researchers and engineers to conduct high-fidelity numerical simulations to model complex fracture mechanisms in advanced materials and structures. Nonetheless, large-scale fracture simulations remain computationally intensive, particularly under loading conditions such as impact and extreme environments. In this context, Machine Learning (ML) techniques have seen a surge in their use for mechanics and computational simulations. In this perspective article, we review the existing research landscape in the recent literature on the application of ML to fracture and damage modelling across different material and structural classes. Specific focus is placed on classifying the ML approaches adopted to model or predict fracture behaviour, followed by an extensive discussion on the challenges and limitations of such approaches. Future directions are proposed with an emphasis on the generality, interpretability and reliability of the ML models. We believe the article serves as a guidance document for engineers and scientists involved in the developmental process of Artificial Intelligence (AI)-driven fracture modelling tools.
{"title":"Machine learning for computational fracture and damage mechanics— Status and perspectives","authors":"Allamaprabhu Ani , Rajesh Nakka , Ghatu Subhash , Jean-François Molinari , Sathiskumar Anusuya Ponnusami","doi":"10.1016/j.engfracmech.2025.111778","DOIUrl":"10.1016/j.engfracmech.2025.111778","url":null,"abstract":"<div><div>Fracture and damage mechanics have evolved remarkably from simple, yet useful Linear Elastic Fracture Mechanics (LEFM) to relatively modern techniques such as Cohesive Zone Model (CZM) and phase-field approaches. The advent of computational power allowed researchers and engineers to conduct high-fidelity numerical simulations to model complex fracture mechanisms in advanced materials and structures. Nonetheless, large-scale fracture simulations remain computationally intensive, particularly under loading conditions such as impact and extreme environments. In this context, Machine Learning (ML) techniques have seen a surge in their use for mechanics and computational simulations. In this perspective article, we review the existing research landscape in the recent literature on the application of ML to fracture and damage modelling across different material and structural classes. Specific focus is placed on classifying the ML approaches adopted to model or predict fracture behaviour, followed by an extensive discussion on the challenges and limitations of such approaches. Future directions are proposed with an emphasis on the generality, interpretability and reliability of the ML models. We believe the article serves as a guidance document for engineers and scientists involved in the developmental process of Artificial Intelligence (AI)-driven fracture modelling tools.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111778"},"PeriodicalIF":5.3,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683229","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}
Pub Date : 2025-12-02DOI: 10.1016/j.engfracmech.2025.111768
Xiaodong Hu , Wenjun Lai , Zhuang Xiong , Haonan Gong , Shou Ma , Weipeng Guan , Fujian Zhou , Jipeng Wen
Distributed acoustic-sensing (DAS) monitoring technology plays an indispensable role in fracturing diagnosis due to its high stability and accuracy. The fracture geometry and fracture propagation trajectory are significant parameters and can be evaluated based on the DAS strain monitoring profile. However, previous research focuses on straight fractures, and there are few studies on the situation when the fracture angle changes. In this paper, considering the change of fracture angle, a new model of the strain in the optic fiber is derived based on the displacement discontinuity method (DDM). Based on the new model, the characteristics of the strain in the optic fiber and fracture geometry under different fracture angles, fracture numbers, cluster spacing, and initiation intervals are analyzed. It is the first to find that the peak location of the strain curve has a correlation relationship with the fracture tip location, thereby describing the fracture propagation trajectory. Based on this cognition, we also first describe the approximate angles of the fractures using the field low-frequency DAS (LF-DAS) data. The research results provide a new idea for the evaluation of fracture propagation trajectory based on the DAS data and can guide the field fracturing operation.
{"title":"Study on the correlation relationship between the fracture propagation trajectory and the strain in the optic fiber when the fracture angle change","authors":"Xiaodong Hu , Wenjun Lai , Zhuang Xiong , Haonan Gong , Shou Ma , Weipeng Guan , Fujian Zhou , Jipeng Wen","doi":"10.1016/j.engfracmech.2025.111768","DOIUrl":"10.1016/j.engfracmech.2025.111768","url":null,"abstract":"<div><div>Distributed acoustic-sensing (DAS) monitoring technology plays an indispensable role in fracturing diagnosis due to its high stability and accuracy. The fracture geometry and fracture propagation trajectory are significant parameters and can be evaluated based on the DAS strain monitoring profile. However, previous research focuses on straight fractures, and there are few studies on the situation when the fracture angle changes. In this paper, considering the change of fracture angle, a new model of the strain in the optic fiber is derived based on the displacement discontinuity method (DDM). Based on the new model, the characteristics of the strain in the optic fiber and fracture geometry under different fracture angles, fracture numbers, cluster spacing, and initiation intervals are analyzed. It is the first to find that the peak location of the strain curve has a correlation relationship with the fracture tip location, thereby describing the fracture propagation trajectory. Based on this cognition, we also first describe the approximate angles of the fractures using the field low-frequency DAS (LF-DAS) data. The research results provide a new idea for the evaluation of fracture propagation trajectory based on the DAS data and can guide the field fracturing operation.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111768"},"PeriodicalIF":5.3,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145734488","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}
Pub Date : 2025-12-01DOI: 10.1016/j.engfracmech.2025.111762
Faustino Mujika
The Mixed-Mode Bending configuration was proposed to characterize the interlaminar fracture of symmetric composite specimens in mixed-mode I/II. In the present study, that test configuration has been applied to obtain pure mode I and pure mode II test conditions in asymmetric specimens, constituted by one or more materials. In a first stage, the conditions for pure mode I and pure mode II have been formulated in a novel way by the J-integral, assuming a small fracture process zone. Those conditions have been applied to asymmetric specimens tested in mixed-mode bending, to obtain testing configurations of pure mode I and pure mode II. For a given asymmetric specimen, different pure mode configurations can be determined, by only varying the loading lever length. The admissible values of normalized loading lever lengths have been determined for three asymmetric systems. Then, a novel analytical approach has been developed to obtain the energy release rate in modes I and II. Several cases have been analysed by the finite element method, using the virtual crack closure technique. The agreement between numerical and analytical results is reasonable in terms of pure modes and energy release rate values.
{"title":"Fracture characterization of asymmetric joints under pure mode I and mode II loading using the mixed-mode bending test","authors":"Faustino Mujika","doi":"10.1016/j.engfracmech.2025.111762","DOIUrl":"10.1016/j.engfracmech.2025.111762","url":null,"abstract":"<div><div>The Mixed-Mode Bending configuration was proposed to characterize the interlaminar fracture of symmetric composite specimens in mixed-mode I/II. In the present study, that test configuration has been applied to obtain pure mode I and pure mode II test conditions in asymmetric specimens, constituted by one or more materials. In a first stage, the conditions for pure mode I and pure mode II have been formulated in a novel way by the <em>J</em>-integral, assuming a small fracture process zone. Those conditions have been applied to asymmetric specimens tested in mixed-mode bending, to obtain testing configurations of pure mode I and pure mode II. For a given asymmetric specimen, different pure mode configurations can be determined, by only varying the loading lever length. The admissible values of normalized loading lever lengths have been determined for three asymmetric systems. Then, a novel analytical approach has been developed to obtain the energy release rate in modes I and II. Several cases have been analysed by the finite element method, using the virtual crack closure technique. The agreement between numerical and analytical results is reasonable in terms of pure modes and energy release rate values.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111762"},"PeriodicalIF":5.3,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683232","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}
Pub Date : 2025-11-30DOI: 10.1016/j.engfracmech.2025.111752
Kai Lu , Wangling Fu , Dong Wang , Tairui Zhang , Yinsheng Li
In this study, systematic investigations on T-stress (i.e., T11 and T33) of side-grooved compact tension (CT) specimens were conducted through three-dimensional finite element analyses (FEAs). CT specimens with crack length-to-width ratios of a/W = 0.2–0.8, thickness-to-width ratios of B/W = 0.1–8 were considered. From the FEAs, the in-plane T11 and out-of-plane T33 solutions at the specimen mid-plane were computed. In addition, fracture toughness tests for both CT and single-edge bending (SE(B)) specimens with B/W = 0.25 and 0.5 were conducted, and the computed T11 and T33 solutions were used to develop a three-parameter constraint-based approach (i.e., Jc-T11-T33). Using the Jc-T11-T33 approach, fracture toughness for CT and SE(B) specimens with B/W = 0.75 and 1.0 was predicted. The predicted fracture toughness values were found to be close to the experimental results with the maximum difference below 7 %. This finding provides a possibility to establish an engineering fracture toughness transferability framework from a laboratory specimen to an actual cracked structure by applying the Jc-T11-T33 approach.
{"title":"Numerical and experimental study on three-dimensional T-stress solutions of side-grooved compact tension specimens","authors":"Kai Lu , Wangling Fu , Dong Wang , Tairui Zhang , Yinsheng Li","doi":"10.1016/j.engfracmech.2025.111752","DOIUrl":"10.1016/j.engfracmech.2025.111752","url":null,"abstract":"<div><div>In this study, systematic investigations on <em>T</em>-stress (i.e., <em>T</em><sub>11</sub> and <em>T</em><sub>33</sub>) of side-grooved compact tension (CT) specimens were conducted through three-dimensional finite element analyses (FEAs). CT specimens with crack length-to-width ratios of <em>a</em>/<em>W</em> = 0.2–0.8, thickness-to-width ratios of <em>B</em>/<em>W</em> = 0.1–8 were considered. From the FEAs, the in-plane <em>T</em><sub>11</sub> and out-of-plane <em>T</em><sub>33</sub> solutions at the specimen mid-plane were computed. In addition, fracture toughness tests for both CT and single-edge bending (SE(B)) specimens with <em>B</em>/<em>W</em> = 0.25 and 0.5 were conducted, and the computed <em>T</em><sub>11</sub> and <em>T</em><sub>33</sub> solutions were used to develop a three-parameter constraint-based approach (i.e., <em>J</em><sub>c</sub>-<em>T</em><sub>11</sub>-<em>T</em><sub>33</sub>). Using the <em>J</em><sub>c</sub>-<em>T</em><sub>11</sub>-<em>T</em><sub>33</sub> approach, fracture toughness for CT and SE(B) specimens with <em>B</em>/<em>W</em> = 0.75 and 1.0 was predicted. The predicted fracture toughness values were found to be close to the experimental results with the maximum difference below 7 %. This finding provides a possibility to establish an engineering fracture toughness transferability framework from a laboratory specimen to an actual cracked structure by applying the <em>J</em><sub>c</sub>-<em>T</em><sub>11</sub>-<em>T</em><sub>33</sub> approach.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"332 ","pages":"Article 111752"},"PeriodicalIF":5.3,"publicationDate":"2025-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145683237","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}
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