Theoretical and Applied Fracture Mechanics最新文献

{"title":"Thermal damage and crack propagation mechanisms of defective crystalline rocks: An experimental and numerical investigation","authors":"Yike Dang ,&nbsp;Zheng Yang ,&nbsp;Shangtong Yang ,&nbsp;Xiaoyu Liu","doi":"10.1016/j.tafmec.2025.105113","DOIUrl":"10.1016/j.tafmec.2025.105113","url":null,"abstract":"<div><div>Water injection-induced shear sliding of natural fractures is a key technology for enhancing reservoir permeability in enhanced geothermal systems (EGS). High temperatures can alter the microstructure around natural fractures, thereby influencing crack propagation. Current studies on the effects of high temperature and defects on the mechanical properties and failure modes of crystalline rocks mostly focus on single variables and have not fully addressed the interaction effects under multivariable conditions. To fill this gap, the present study investigates the mechanical properties and failure characteristics of thermally treated granite with defects at different angles. Using discrete element method (DEM) simulations, the failure mechanisms of thermally damaged defective crystalline rocks are analyzed from a microscopic perspective. The results showed that: (1) As the temperature increased, the compaction phase in the stress–strain curve gradually extended. The curve evolved from having no plastic region to exhibiting a distinct plastic region. The peak strength and elastic modulus fluctuated significantly between room temperature and 300 °C (with some samples also treated at 450 °C). After 450 °C, both peak strength and elastic modulus decreased as the temperature continued to rise. (2) The primary cause of thermally induced crack formation is the difference in thermal expansion between minerals, with defects playing a relatively minor role. Thermally induced cracks tend to form along the short axis of mineral grains or at irregular interfaces. Thermal damage is more pronounced in samples with uneven grain size and shape distributions compared to those with uniform grains. (3) Below 450 °C, tensile cracks primarily form at the tips of defects. Once these cracks initiate, they tend to deflect due to mechanical differences between minerals. Crack propagation is controlled by local grain morphology, making it difficult for cracks to form a continuous propagation path. Above 450 °C, shear cracks dominate at the defect tips. Once these cracks initiate, they no longer follow paths of least resistance but instead propagate in multiple directions.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105113"},"PeriodicalIF":5.6,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749105","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":"Mechanical characteristics and progressive failure mechanism of prefabricated defective marble under hydro-mechanical coupling","authors":"Weichen Huang,&nbsp;Yun’an Li,&nbsp;Dunming Zhu","doi":"10.1016/j.tafmec.2025.105130","DOIUrl":"10.1016/j.tafmec.2025.105130","url":null,"abstract":"<div><div>The mechanical response characteristics and crack propagation patterns of defective rock under hydro-mechanical coupling conditions are critical scientific issues for stability evaluation in deep underground engineering. In this study, conventional triaxial compression tests with different confining pressures (0–30 MPa) and pore pressures (0–25 MPa) were performed, and the strength evolution law of the prefabricated defective marbles was revealed. Based on the three-dimensional discrete element numerical simulation method, the crack initiation time sequence and crack propagation patterns of the defective marble under hydro-mechanical coupling were quantitatively analyzed. The results showed that the restraining effect of confining pressure (σ₃) slowed the propagation rate of microcracks and reduced the number of microcracks. σ₃ significantly increased the stress thresholds of the prefabricated defective marble. The pore pressure (P_w) accelerated the propagation rate of microcracks through the synergistic effect of the effective stress weakening and hydraulic splitting drive. Increased P_w led to lower stress thresholds in prefabricated defective marble. The stress thresholds of a prefabricated defective marble under hydro-mechanical coupling exhibited a significant sensitivity divergence law. The difference in the sensitivity gradient was shown as σ_cd &gt; σ_ci &gt; σ_p. In addition, the crack initiation angle prediction model quantitatively showed that the magnitude of the crack initiation angle was negatively correlated with σ₃ and was positively correlated with P_w. The research results provide a theoretical basis and important reference for the stability evaluation of defective rock mass in deep engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105130"},"PeriodicalIF":5.6,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749158","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":"Experimental and theoretical study on the competitive initiation of tensile cracks in shale under different loading modes","authors":"Shuai Heng ,&nbsp;Hongyu Liu ,&nbsp;Chenxing Wang ,&nbsp;Wen Wang ,&nbsp;Zhonghu Wu","doi":"10.1016/j.tafmec.2025.105123","DOIUrl":"10.1016/j.tafmec.2025.105123","url":null,"abstract":"<div><div>The semi-circular bend (SCB) test has been extensively utilized to investigate the fracture characteristics of rocks under various loading modes. However, a fundamental issue that has not been fully understood is why competitive initiation of tensile cracks typically occurs under different loading modes. Therefore, SCB tests were conducted on shale samples to explore the competition between tensile and shear fracture under various loading modes. Three techniques were employed to ascertain the fracture modes/mechanisms: digital image correlation (DIC), thin-section observation and micro-morphology of fracture. Concurrently, theoretical analyses were conducted on the competition between tensile and shear fracture for notches under various loading modes. The findings indicated that the fracture modes of initiated cracks can be determined from the displacement fields captured by DIC. Only opening displacements were observed for the initiated cracks under various loading modes, thereby demonstrating that the cracks were all produced by mode-I fracture. The initiated cracks exhibited solely cleavage and intergranular fracture characteristics, with no striations or shear marks evident on the fracture surfaces. Shear fracture is not competitive in comparison to tensile fracture, even under pure mode-II and compression-shear loading conditions. Therefore, tensile cracks are observed to initiate preferentially from the notch tip under various loading modes. Typically, negative (compressive) T-stress weakens the competitive initiation of tensile cracks, while positive (tensile) T-stress enhances it. Shear fracture may occur at notches exhibiting low positive or negative <em>K</em>_I values and high compressive T-stress.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"140 ","pages":"Article 105123"},"PeriodicalIF":5.6,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144781316","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":"Matrix interpolation-based parametric model order reduction for stationary crack problems under dynamic loading in functionally graded materials","authors":"Prahallad Pattanayak,&nbsp;Ganesh S. Pawar,&nbsp;Salil S. Kulkarni","doi":"10.1016/j.tafmec.2025.105101","DOIUrl":"10.1016/j.tafmec.2025.105101","url":null,"abstract":"<div><div>This paper aims to present efficient parametric model order reduction (PMOR) strategies to evaluate the dynamic stress intensity factors (DSIFs) in functionally graded materials. PMOR is a method of generating low-cost reduced order models (ROMs) by preserving properties of the original high dimensional system. The parameters in a numerical model can be material properties, geometrical aspects of the crack, loading, and initial and boundary conditions. The variation in any of the parameters can affect the dynamics of the system. In numerical analysis, it is often required to evaluate the system response at multiple values of these parameters to completely characterize the fracture behavior, which is a computationally intensive process. Therefore, PMOR approaches are highly applicable in such situations to reduce the overall computational effort. In this work, projection-based PMOR approaches are presented for solving fracture problems. Here, the elastic modulus is treated as a parameter, and its exponential gradation along the horizontal and vertical directions is achieved by selecting two unique exponents. The efficiency and accuracy of the PMOR methods are demonstrated by solving a few two-dimensional plane strain stationary Mode I and mixed mode crack problems under dynamic loading conditions.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105101"},"PeriodicalIF":5.6,"publicationDate":"2025-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749123","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":"Investigating fracture behavior of granite under freeze–thaw cycles based on DIC-Mask2former: Macro-micro study of dynamic mode-I fractures","authors":"Jinlong Zhang ,&nbsp;Yao Song ,&nbsp;Zhongchang Wang ,&nbsp;Zhongwen Yue","doi":"10.1016/j.tafmec.2025.105120","DOIUrl":"10.1016/j.tafmec.2025.105120","url":null,"abstract":"<div><div>The progression of geotechnical projects in cold regions is increasingly affected by freeze–thaw (F-T) cycles under natural conditions, which induce damage and degradation in rocks, posing significant risks to engineering safety. This study performed a series of impact experiments on cracked straight-through Brazilian disc (CSTBD) samples subjected to varying F-T cycles (0, 10, 20, 30, 40) using a split Hopkinson pressure bar (SHPB) test system. Experimental data were captured through high-speed imaging and processed using digital image correlation (DIC) and the Mask2former image segmentation model in deep learning to extract parameters such as displacement field, fracture process zone (FPZ), strain field, microcrack count, crack profile, crack area, and dynamic stress intensity factor (<span><math><msubsup><mtext>K</mtext><mrow><mi>I</mi></mrow><mtext>d</mtext></msubsup></math></span>). The relationship between F-T cycles and these parameters was analyzed progressively. Results showed that F-T cycles did not alter the macroscopic fracture mode of the main crack. However, with an increasing number of F-T cycles, the energy required for rock cracking decreased, accompanied by a declining trend in <span><math><msubsup><mtext>K</mtext><mrow><mi>I</mi></mrow><mtext>d</mtext></msubsup></math></span>. On a microscopic scale, the F-T cycles influenced the microcrack formation at the crack initiation stage, with the number of microcracks increasing during the first 30 cycles and subsequently decreasing after 40 cycles. Additionally, the FPZ count at crack initiation increased with more F-T cycles. The cumulative damage caused by multiple F-T cycles altered the microscopic structure of the rock, indirectly impacting the failure characteristics during crack initiation. These characteristics persisted into the secondary rock failure stage, although F-T cycles did not directly influence the area growth rate of secondary failure cracks.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105120"},"PeriodicalIF":5.0,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713451","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":"Physically based fatigue short crack growth concept","authors":"A. Nosikov","doi":"10.1016/j.tafmec.2025.105122","DOIUrl":"10.1016/j.tafmec.2025.105122","url":null,"abstract":"<div><div>In this work a novel fatigue short crack growth concept is proposed and developed. This method considers fracture process zone ahead of the crack depending on material microstructure which is simulated based on modified Barrenblatt’s and Dugdale’s concept. Microstructural fracture modes i.e intergranular, transgranular or mixed mode as well as a physical fracture modes i.e. brittle, semi-brittle and ductile fractures can be considered based on this approach. This method turns into standard Linear Fracture Mechanics (LFM) method when crack becomes a large crack and fracture process zone is localised near crack tip. On the other hand, a fatigue limit occurs as a threshold parameter of fatigue failure for vanishingly small cracks that is in line with standard fatigue theory. Based on this method it can be concluded that a strain of the material microstructural area ahead of the crack tip can be considered as a driving force of fatigue crack growth. A short crack arrest mechanism can be defined based on maximum strain criteria: a mechanically short crack cannot grow when the strain of relevant microstructural area ahead crack tip is less than certain critical magnitude. This fatigue short crack growth model includes several well-known material parameters: Paris law constants, yield stress, fatigue limit. Also, this concept uses a specific material microstructural parameter that can be defined based on fatigue tests. Proposed concept has been validated based on fatigue specimen tests.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105122"},"PeriodicalIF":5.6,"publicationDate":"2025-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749114","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 averaged strain energy density based approach to predict the static notch effect in short fibre composites. Part 1: Theoretical formulation","authors":"Michele Zappalorto ,&nbsp;Matteo Pastrello ,&nbsp;Mauro Ricotta ,&nbsp;Filippo Coppola","doi":"10.1016/j.tafmec.2025.105115","DOIUrl":"10.1016/j.tafmec.2025.105115","url":null,"abstract":"<div><div>In this work the Averaged Strain Energy Density (ASED) criterion is reformulated for notched bodies made of orthotropic materials and proposed as an effective approach to predict the static notch effect in short fibre composites.</div><div>The first part of this study focuses on the theoretical formulation, with the aim to provide a new set of analytical solutions for the ASED evaluated over a well-defined control volume close to U- and blunt V-shaped notches in orthotropic plates under Mode I loading conditions. The analytical solutions presented are derived taking advantage of some recent expressions for the stress distribution near blunt notches in orthotropic solids, as developed by the authors. Key parameters considered include the notch tip radius, notch opening angle and the elastic properties of the orthotropic material.</div><div>As also discussed in the second part of this contribution, the ASED approach offers insights into the notch sensitivity of short fibre composites, providing a foundation for further investigation into the mechanical behaviour of this class of materials.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105115"},"PeriodicalIF":5.6,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749260","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 the impact dynamic fracture of T-shaped beam-column specimens with complex prefabricated cracks","authors":"Wang Kai ,&nbsp;Lu Chunliu ,&nbsp;Li Hongchao ,&nbsp;Xue Yaodong","doi":"10.1016/j.tafmec.2025.105111","DOIUrl":"10.1016/j.tafmec.2025.105111","url":null,"abstract":"<div><div>In large-scale industrial plants, high-rise buildings and bridges, T-beams, as key load-bearing components, may be subjected to dynamic loads such as explosions, impacts, etc., which are complex and most of the structures are damaged in practice. Therefore, in this paper, hammer impact experiments were carried out on different numbers of T-beams with internal tension cracks, and the dynamic fracture characteristics of T-beams were investigated by using the dynamic focal dispersion line test system. The results show that in the impact dynamic fracture study of T-beam specimens with complex prefabricated cracks, the number of cracks increases, but the number of cracks through the specimen does not increase simultaneously, and only the prefabricated cracks in the beams close to the loading point start to crack. When only the cracks at the beam end increased, after the beam crack penetration, the residual stresses caused the beam-column intersection to crack twice, expanding in the core in a “C” shape, and the fracture toughness of the node decreased to 0.8 MN/m^3/2, with a decrease of about 33 %. In the three specimens containing internal prefabricated cracks, the end with high stress expanded first, and then the unloaded stress increased significantly and caused the other end to expand, with the maximum increase in stress intensity factor reaching 166 %. The number and location of prefabricated cracks had a significant effect on the crack expansion rate and expansion path. The more the number of cracks, the slower the overall expansion, and the average speed of the specimen with a single crack is 244 m/s; the fastest expansion of internal cracks, the stress intensity factor of the crack initiation on the left side of the column is only 0.63MN/m^3/2, and the post-crack initiation of the column cracks affects the expansion of the beam cracks. The results of the study can provide theoretical references for the dynamic response problems and damage laws of cracked structures of T-beams.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105111"},"PeriodicalIF":5.6,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749116","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":"Low-temperature fracture toughness of ZG300-500H cast steel and fracture prediction using neural networks","authors":"Yan Lu ,&nbsp;Zhanxiang Liu ,&nbsp;Peipeng Wang ,&nbsp;Pengxiang Wang ,&nbsp;Xinyang Liu","doi":"10.1016/j.tafmec.2025.105117","DOIUrl":"10.1016/j.tafmec.2025.105117","url":null,"abstract":"<div><div>Monotonic tensile tests and three-point bending experiments are conducted on ZG300-500H cast steel at various low temperatures, including 20 °C, 0 °C, −20 °C, −40 °C, −60 °C, and − 80 °C. The load–displacement (<em>P</em>-<em>V</em>) curves, crack-tip opening displacement (CTOD) values, and crack extension resistance (<em>J</em>-<em>R</em>) curves are obtained for the cast steel. The parameters of the Gurson-Tvergaard-Needleman (GTN) model at low temperatures have been calibrated through a back propagation (BP) neural network, which relies on both experimental fracture toughness data and finite element simulation results. The calibrated GTN model is employed to predict the fracture toughness of ZG300-500H cast steel, utilizing three-point bending specimens that feature varying degrees of out-of-plane constraints. The results indicate that as temperature decreases, both the CTOD value and the <em>J</em>-<em>R</em> curve exhibit a decrease trend. The void volume fractions of the GTN model parameters are affected by temperature. The initial void volume fraction <em>f</em>₀, the critical void volume fraction <em>f_C</em>, and the final void volume fraction <em>f_F</em> all decrease as temperature drops, whereas the volume fraction of void nucleating particles <em>f_N</em> increases. Among these parameters, <em>f_C</em> exhibits the greatest sensitivity to temperature changes, decreasing by 47.67 % from 20 °C to − 80 °C. The BP neural network is capable of effectively establishing a nonlinear relationship between the fracture characteristics of cast steel and GTN model parameters. The calibrated GTN model demonstrates its ability to accurately predict the fracture toughness of ZG300-500H cast steel.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105117"},"PeriodicalIF":5.6,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749122","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":"Analytical modeling of interfacial crack tip stress concentration in mode II fracture energy","authors":"Wen Li","doi":"10.1016/j.tafmec.2025.105119","DOIUrl":"10.1016/j.tafmec.2025.105119","url":null,"abstract":"<div><div>The stress field at the forefront of an interface crack exhibits oscillatory singularity, and classical Täljsten model of Mode II interface fracture energy, which assume plane section deformation on both sides of the interface, neglect the stress concentration normal to the interface at the crack tip. This study proposes a novel quantitative approach to assess the influence of crack tip stress concentration on interfacial Mode II fracture energy models. Considering the order − of − magnitude in material thickness across the interface, the concept of “finite stress concentration” is introduced, wherein only the thinner material is assumed to undergo plane section deformation. A concise finite element method is employed to quantitatively analyze the stress concentration, developing an analytical model that relates crack tip stress to key parameters such as elastic modulus and thickness. Based on this, a refined fracture energy model for interfacial Mode II cracks incorporating stress concentration is established. Validation against experimental data from the previous literature demonstrates that the developed model reduces evaluation errors by an order of magnitude compared to the classical model. This paper can offer a new evaluation methodology for quantifying stress concentration at interface crack tip under various failure modes and enables more accurate assessment of interfacial Mode II fracture energy.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105119"},"PeriodicalIF":5.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713097","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}