Theoretical and Applied Fracture Mechanics最新文献

{"title":"Study and mechanism analysis on fracture mechanical properties of steel fiber reinforced recycled concrete (SF-R-RC)","authors":"Zhenpeng Yu ,&nbsp;Tianqian Wu ,&nbsp;Xinjian Sun ,&nbsp;Lei Xie ,&nbsp;Kequan Yu","doi":"10.1016/j.tafmec.2024.104780","DOIUrl":"10.1016/j.tafmec.2024.104780","url":null,"abstract":"<div><div>Recycled concrete has deficiencies in its overall performance due to the deteriorated properties of the recycled aggregate (RA) used. Based on the RA characteristics and fiber reinforcement mechanism, designing recycled concrete by adding steel fiber (SF) and enhancing RAs in a coordinated manner can effectively improve the overall performance of recycled concrete. Therefore, this paper considers the SF content and RA enhancement to study the fracture mechanical properties of steel fiber reinforced recycled concrete (SF-R-RC), and the main conclusions are as follows: the fracture mechanical properties of SF-R-RC are significantly affected by aggregate enhancement and SF content. Without the SFs, the strengthened coated recycled aggregate concrete (CRAC) was better than unreinforced recycled aggregate concrete (RAC) in terms of the unstable fracture load, fracture energy, initial fracture toughness and unstable fracture toughness, but weaker than normal aggregate concrete (NAC). The increase in the unstable fracture load, fracture energy, initial fracture toughness and unstable fracture toughness of NAC, RAC and CRAC with the increase in SF content was observed, with CRAC showing the most significant increase in these fracture parameters. Applying digital image correlation (DIC) and acoustic emission (AE) techniques, the effect of SF content and RA enhancement method on the crack evolution process and damage distribution law of SF-R-RC was studied. Meanwhile, the microscopic testing technique was used to reveal the mechanism of the influence of SF and RA enhancement on the fracture mechanical properties of SF-R-RC. The research results of this paper provide a theoretical basis for the application of RA enhancement and SF reinforcement methods of recycled concrete in practical engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104780"},"PeriodicalIF":5.0,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743174","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":"Simulation of mixed mode I-II fatigue crack propagation in concrete with different strengths","authors":"Hong Chen ,&nbsp;Zhimin Wu ,&nbsp;Rena C. Yu","doi":"10.1016/j.tafmec.2024.104779","DOIUrl":"10.1016/j.tafmec.2024.104779","url":null,"abstract":"<div><div>The mode-I fatigue crack propagation in concrete has been extensively studied. However, many concrete structure failures occur subjected to mixed-mode fatigue loads in practice. The accurate predictions for the mixed mode I-II fatigue crack propagation and fatigue life are crucial for evaluating the structural safety of concrete constructions. In this paper, the mixed mode I-II fatigue crack propagation process on concrete with different strengths is simulated using the fatigue tension-softening constitutive model and the crack propagation criterion of the initial fracture toughness as a parameter (SIF-based criterion). The numerical results indicated that the fatigue crack length decreases with increasing the concrete strength for a given fatigue load level, but the fatigue life significantly increases with concrete strength. Further, a modified Paris law is presented on the basis of the numerical results for concrete with different strengths. With the known tensile strength of concrete, the mixed mode I-II fatigue crack propagation rate of concrete with different strengths can be presented. The proposed model in this study is useful in further predicting the fatigue life of concrete structures under mixed-mode fatigue loads.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104779"},"PeriodicalIF":5.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743176","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":"Effect of the surface morphology of 3D printed titanium substrates on the mode I fracture toughness of metal-metal and metal-composite bonded joints","authors":"Michele Gulino ,&nbsp;Rosemere de Araujo Alves Lima ,&nbsp;Fabrizio Moroni ,&nbsp;Alessandro Pirondi ,&nbsp;Sofia Teixeira de Freitas","doi":"10.1016/j.tafmec.2024.104778","DOIUrl":"10.1016/j.tafmec.2024.104778","url":null,"abstract":"<div><div>Parts manufactured with Laser Powder Bed Fusion (LPBF) are drawing interest in the adhesive joints research because of their high surface roughness, which is usually associated with good adhesion. This work aims to assess the adhesion strength of the inherent surface morphology of LPBF manufactured titanium.</div><div>Double Cantilever Beam (DCB) tests were carried out to determine the mode I fracture toughness of joints comprising as-printed titanium (Ti6Al4V) adherends, namely titanium-titanium secondary bonded and titanium-Carbon Fibre Reinforced Polymer (CFRP) co-bonded joints. The effect of high-temperature oxidation on the fracture toughness was also evaluated by testing a batch of joints in which the titanium underwent a post-printing thermal treatment. The as-printed specimens were compared to the same type of joints but with sandblasted titanium adherends to evaluate the effect of this surface pre-treatment on the value of fracture toughness.</div><div>The results indicate that non-oxidised titanium joints with untreated adherends had an average of 11% higher fracture toughness than their sandblasted counterparts. On the other hand, sandblasting proved beneficial for oxidised joints, increasing the fracture toughness by 64% on average over the untreated samples.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104778"},"PeriodicalIF":5.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fatigue characterisation of structural steel by means of the small punch test: Development of a methodology","authors":"S. Otero,&nbsp;G. Álvarez,&nbsp;M.M. Llera,&nbsp;C. Rodríguez","doi":"10.1016/j.tafmec.2024.104772","DOIUrl":"10.1016/j.tafmec.2024.104772","url":null,"abstract":"<div><div>Knowledge of the fatigue behaviour of materials is fundamental to the safe design of structures. Standardised tests are used for this purpose, but their application requires a considerable amount of material, which in many cases is not available. To overcome this problem, the use of miniature tests would be the optimal solution. This work analyses the application of the Small Punch Test (SPT) to characterise the fatigue behaviour of structural steels. To this end, an experimental methodology has been developed to analyse not only where SPT-fatigue damage initiates and how it propagates, but also its relationship with changes in specimen compliance. Based on this methodology, different S_PT-N <em>iso</em>-damage curves and the SPT-fatigue limit have been obtained for two structural steels. By comparing these results with those obtained from rotating beam fatigue tests, a simple correlation has been proposed between the fatigue limits obtained from SPT and rotating beam fatigue tests.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104772"},"PeriodicalIF":5.0,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-Proportional mixed mode plastic zones via finite elements and artificial neural networks","authors":"V. Infante ,&nbsp;R. Baptista","doi":"10.1016/j.tafmec.2024.104777","DOIUrl":"10.1016/j.tafmec.2024.104777","url":null,"abstract":"<div><div>The plastic zone developed around a fatigue crack tip can affect both fatigue and fracture material behaviour. Predicting the plastic zone shape and size under cyclic conditions can, therefore, enhance fatigue crack propagation analysis. While there are theoretical solutions for the elastic stress and strain fields under pure or mixed mode conditions around the crack tip, solutions for plastic fields must be determined using experimental or numerical approaches. The Compact Tension Shear (CTS) specimen has been extensively used to analyse plastic zones under proportional conditions, but when non-proportional conditions are applied the number of necessary analyses for a reasonable understanding of the plastic zone shape and size around the crack tip can increase exponentially. To address this problem, a combined approach was used to reduce the number of required plastic zone simulations. First, a hand selected number of loading configurations were simulated using the Finite Element Method (FEM), predicting the plastic zone shape and size. Then, an Artificial Neural Network (ANN) was trained to predict the plastic zone under different conditions. Using only 18 configurations for 3 different loading conditions, the trained ANN was able to accurately predict the plastic zone shape and size for both tensile and shear propagation modes. The network can now be used to predict the plastic zone influence on fatigue and fracture behaviour, without the need for further numerical analysis. The paper results also show that crack propagation direction can be correlated and predicted using the applied loads and the resulting plastic zone.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104777"},"PeriodicalIF":5.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721135","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":"Assessment of measurement uncertainty associated with fracture toughness calculation based on energy release rate in spherical indentation tests","authors":"Cláudio Costa Souza ,&nbsp;Regina Paula Garcia Moura ,&nbsp;Waldek Wladimir Bose Filho ,&nbsp;Rosenda Valdés Arencibia","doi":"10.1016/j.tafmec.2024.104775","DOIUrl":"10.1016/j.tafmec.2024.104775","url":null,"abstract":"<div><div>This work aims to evaluate the uncertainty associated with the fracture toughness of 4130 <!--> <!-->M steel obtained via instrumented indentation tests and the methodology proposed by Zhang, Wang and Wang (2019). These authors take the energy release rate as a basis to determine fracture toughness. In this study, the uncertainty was assessed using the Guide to the Expression of Uncertainty of Measurement (GUM) and Monte Carlo methods. For uncertainty assessment, all measurands and input variables were identified based on the equations proposed by these authors. Then, the standard uncertainty associated with each input variable was calculated by applying the GUM method. To determine the uncertainty associated with the energy release rate <em>J_SIT</em> the Monte Carlo method was applied. The results obtained showed that the expanded uncertainty associated with <em>J_SIT</em> considering three tests was 1.486 N.mm⁻¹. This uncertainty represents 7.25 % of the average <em>J_SIT</em> value (20.490 <!--> <!-->N.mm⁻¹). The expanded uncertainty associated with <em>K_IC</em> was 7.520 MPa.m^0.5. These represent 3.82 % of the average <em>K_IC</em> (196.562 MPa.m^0.5) value obtained. This paper demonstrates that despite the complexity of the mathematical equation proposed by Zhang, Wang and Wang (2019), to obtain fracture toughness via instrumented indentation tests, the uncertainty associated can be successfully accessed by combining the GUM and Monte Carlo methods. This work showed that the application of the instrumented indentation technique with the methodology proposed by Zhang, Wang and Wang (2019) provided fracture toughness values with excellent quality under the experimental conditions used in this study.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104775"},"PeriodicalIF":5.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721136","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":"An analytical model based on cross-sectional geometric characteristics for calculating crack opening displacement in reinforced concrete beams","authors":"Chunyu Fu ,&nbsp;Yunpeng Liu ,&nbsp;Yongsheng Lao ,&nbsp;Jianming Wang","doi":"10.1016/j.tafmec.2024.104770","DOIUrl":"10.1016/j.tafmec.2024.104770","url":null,"abstract":"<div><div>To accurately calculate crack opening displacement (COD) in reinforced concrete beams, this study establishes a relationship between COD, cross-sectional rotation, and strain distribution by utilizing the geometric relationships of deformation in the cracked region. Based on the varying bond characteristics between the reinforcement and concrete, a method is developed to calculate COD by analyzing the nonlinear strain distribution in both materials and determining the sectional rotation of the cracked beam. This proposed method was validated through experimental tests on a cracked reinforced concrete beam model. The results indicate that, as the load increases, the bond stiffness between the reinforcement and concrete diminishes, leading to nonlinear changes in the tensile strain of the reinforcement. This results in an increasing slope of the crack opening displacement with increasing load, showing a clear nonlinear trend, even under small loads. However, a linear relationship is observed between crack opening displacement and structural deflection. The proposed method, based on the geometric relationship of sectional deformation, accurately predicts these nonlinear deformations, offering a novel approach for calculating crack opening displacements.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104770"},"PeriodicalIF":5.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721137","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":"Influence of freeze–thaw cycles on fracture behaviors of Nano-SiO2 modified high-strength high- ductility alkali-activated material","authors":"Li Li ,&nbsp;Peng Jin ,&nbsp;Kun Zhang ,&nbsp;Chenyu Yan ,&nbsp;Ning Zhang ,&nbsp;Yang Li ,&nbsp;Qi Feng","doi":"10.1016/j.tafmec.2024.104774","DOIUrl":"10.1016/j.tafmec.2024.104774","url":null,"abstract":"<div><div>Nano-SiO₂ (NS) can effectively improve the mechanical properties of cement-based materials and alkali-activated materials, but its effect on the durability and fracture properties of high-ductility concrete has not been revealed. The influences of freeze–thaw cycles on the bending fracture behaviors of NS modified high-strength high-ductility alkali-activated material (HSHDAM) were studied herein. There were 4 wt content of NS (0 %, 4 %, 8 % and 12 %) and 4 numbers of freeze–thaw cycles (25, 50, 75 and 100) assessed. The results indicated that with the increase of freeze–thaw cycles number, the compressive strength, dynamic modulus of elasticity, fracture toughness of initiation and instability and fracture energy of HSHDAM were all decreased continually and significantly, but the ductility index was increased. With the increase of the NS weight content, the compressive strength, dynamic modulus of elasticity, fracture toughness of initiation and instability, and fracture energy and ductility index of HSHDAM were all increased continually, while the bending strength seems to be optimal at 4 % NS content. 75 freeze–thaw cycle was the threshold value for the strengthening effect of NS on bending strength and ductility index. With the addition of NS, the better bonding properties of polyethylene fiber, more fully cracking behaviors, and compact alkali-activated matrix contributed to these good fracture and anti-freeze–thaw behaviors. The addition of NS can alleviate the deterioration of HSHDAM mechanics and fracture properties caused by freeze–thaw cycle.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104774"},"PeriodicalIF":5.0,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721196","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":"Progressive failure characteristics and damage constitutive model of fissured rocks under water–rock coupling","authors":"Jiyuan Hu ,&nbsp;Dongfa Sheng ,&nbsp;Feifei Qin ,&nbsp;Yingchao Zhu ,&nbsp;Ziheng Li ,&nbsp;Taicong Chen ,&nbsp;Hongquan Yu","doi":"10.1016/j.tafmec.2024.104765","DOIUrl":"10.1016/j.tafmec.2024.104765","url":null,"abstract":"<div><div>An in-depth study of the damage characteristics of rocks under water–rock coupling (WRC) and the weakening mechanism of their mechanical properties is of great guiding significance for practical engineering. This paper studies the influence of WRC on the mechanical properties, energy dissipation characteristics and damage evolution law of fractured limestone during long-term immersion damage, revealing the mechanical behavior of fractured rock mass in a water environment. To explore the influence of the nonlinear process of macroscopic and mesoscopic damage evolution on the mechanical behavior of fractured rock mass, based on the evolution law of dissipated energy of rock specimens, this paper proposes a critical point of pore compaction and constructs a strain difference function between the compaction stage and the linear elastic stage. On this basis, a segmented damage constitutive model consisting of an empirical pore compaction model and a macro-meso coupled damage constitutive model was established. The model was compared with the calculation results of the model that did not consider the pore compaction stage. It was found that the strength characteristics and damage evolution law of the fractured rock mass revealed by this model were more in line with the experimental results, thus verifying the rationality of the model. Finally, damage evolution and the physical significance of the model parameters proposed in this paper were systematically discussed.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104765"},"PeriodicalIF":5.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721133","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":"Modelling unstable crack propagation in concrete by finite element method with continuous nodal stress","authors":"Wang Zhang ,&nbsp;Zhimin Wu ,&nbsp;Rena C. Yu ,&nbsp;Jianjun Zheng","doi":"10.1016/j.tafmec.2024.104767","DOIUrl":"10.1016/j.tafmec.2024.104767","url":null,"abstract":"<div><div>Cracks in concrete will propagate unstably due to excessive shear stress, interactions at the rock-concrete interface, or sudden energy release, significantly compromising structural bearing capacity. To investigate this phenomenon, a nonlinear numerical method for modelling mixed-mode I-II crack propagation has been developed. This approach integrates dynamic equilibrium with a fictitious crack model and an initiation fracture toughness criterion. Key innovations include the incorporation of a finite element method with continuous nodal stress to enhance calculation accuracy, the utilization of kinetic energy to compensate for abrupt losses of strain energy during crack propagation, and the consideration of the deformation of the distributive beam and its interactions with specimens and supports. It was validated by modelling classic benchmarks for the dynamic initiation and propagation of brittle materials under mode I and mixed-mode I-II loading, and applied to analyse unstable crack propagation in concrete for four-point shear (FPS) beam specimens under various ratios of mode I and II stress intensity factors (<em>K</em>_I/<em>K</em>_II = 0 to 5.32) and loading rates (2 × 10^-7 m/s to 2 × 10^-3 m/s). Results indicated that the method effectively captures unstable crack propagation, with load-crack mouth shear displacement (CMSD) curves and crack propagation trajectories closely matching the experimental data. Furthermore, it was observed that when the elastic strain energy within the concrete beam exceeds the residual energy stored in the extended cracks, the crack transitions from stability to instability; conversely, if the elastic strain energy is less than or approximately equal to the residual energy, the crack decelerates and returns to stability. Additionally, parametric analyses reveal that lower distributive beam stiffness, shorter preset crack lengths, reduced concrete fracture energy, and a less robust cohesive force–displacement curve increase the likelihood of unstable crack propagation in concrete.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"135 ","pages":"Article 104767"},"PeriodicalIF":5.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743172","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}