Theoretical and Applied Fracture Mechanics最新文献

{"title":"Reverse bend experiments on the base plate and discussion of the appropriate amount of reverse bending for precrack straightness (Effect of the reverse bend process on the CTOD toughness evaluation and understanding of its mechanisms)","authors":"Tomoya Kawabata ,&nbsp;Hoichi Kitano ,&nbsp;Takumi Ozawa ,&nbsp;Yoshiki Mikami","doi":"10.1016/j.tafmec.2025.104869","DOIUrl":"10.1016/j.tafmec.2025.104869","url":null,"abstract":"<div><div>Measurements of the critical value of the crack-tip opening displacement (CTOD) of welded joints often suffer from weld residual stresses, which prevent the introduction of a straight precrack front. In this study, the effects of reverse bending, a proven method for straightening the crack front shape, on evaluations of the critical CTOD are investigated. To compare the differences in the evaluation results, the authors used a base plate without residual stress inside the material for their experiments. Five different reverse bending treatments were applied to a 50 mm thick base metal, and the effects of reverse bending were evaluated via CTOD tests at low temperatures. Additionally, numerical simulations were carried out via the finite element method to exclude the effects of <em>a</em>₀/<em>W</em> and <em>a</em>_f, which cannot be unified in the experiments, and to understand the mechanism. After reverse bending and unloading, the tensile residual stress is distributed at the notch edge, and a high stress intensity at the fatigue crack tip during CTOD testing can be expected. In addition, when the amount of reverse bending is increased to <em>L</em>_r = 1.35, the compressive residual stress distribution in front of the specimen expands, and the <em>P–V</em>_g curve clearly decreases, which may impair the precrack shape flatness. Therefore, the controlled range of <em>L</em>_r should be at least less than 1.35.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104869"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429423","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":"Dynamic compressive micro-macro fracture mechanism with the water-saturated strengthening and weakening effect in brittle rocks","authors":"Xiaozhao Li ,&nbsp;Qiulin Luo ,&nbsp;Fayuan Yan ,&nbsp;Chengzhi Qi","doi":"10.1016/j.tafmec.2025.104871","DOIUrl":"10.1016/j.tafmec.2025.104871","url":null,"abstract":"<div><div>The dynamic compressive mechanical properties of water-saturated brittle rocks are of significant practical importance for assessing the stability of deep underground rock masses during excavation. The coupled dynamic effect of free water and microcrack extension within the rocks severely affects the dynamic compressive mechanical properties of saturated rocks. However, there is a significant lack of research on the mechanisms relating the microcrack evolution to the macroscopic deformation behavior of saturated brittle rocks under dynamic compressive loading. This article aims to propose a feasible micro–macro fracture model to explain the enhancement and weakening mechanisms of free water on the dynamic mechanical properties of rocks. Based on the stress–strain constitutive model of dry rock under quasi-static crack extension action, the stress–strain constitutive model of water-saturated rock under quasi-static action is obtained by combining the change of mechanical parameters of rock with free water. Then the quasi-static fracture toughness and dynamic fracture toughness relationship, the crack extension rate and crack opening rate relationship and the crack extension rate and strain rate relationship are introduced and combined with the Stefan effect to derive the stress–strain constitutive model for water-saturated brittle rocks under dynamic compression. And the reasonableness of the theoretical model is verified by the experimental results. The changes in the intercrack friction coefficient <em>µ</em>, initial damage <em>D</em>₀ and quasi-static fracture toughness <em>K</em>_ICQ due to free water have a weakening effect on the dynamic mechanical properties of the rock. The alterations in dynamic fracture toughness amplification factor <em>K</em>_V resulting from changes in the quasi-static elastic modulus <em>E</em> and density <em>ρ</em>, along with the Stefan force <em>F</em>_S effect, contribute to the enhancement of the dynamic mechanical characteristics of the rock. The changes in mechanical parameters and the Stefan effect together constitute the strengthening and weakening mechanisms through which free water affects the dynamic mechanical properties of the rock. And discusses the effects of confining pressure and strain rate on the dynamic compressive strength and crack initiation stress of water-saturated rock. These findings provide theoretical support for the stability analysis of saturated rock masses during deep underground excavation.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104871"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143429420","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 wet-dry history on the mixed fracture properties of dense asphalt mixture based on ASCB test","authors":"Qinglin Guo ,&nbsp;Panpan Zuo ,&nbsp;Lili Li ,&nbsp;Keyi Wang ,&nbsp;Zhiyong Liu ,&nbsp;Li Zhang ,&nbsp;Wenli He ,&nbsp;Pengfei Liu","doi":"10.1016/j.tafmec.2025.104873","DOIUrl":"10.1016/j.tafmec.2025.104873","url":null,"abstract":"<div><div>The coupling effects of traffic loads and rainfall may cause premature cracking in asphalt layer. Consequently, it is of interest to study the influence of rainfall on the fracture resistance of asphalt mixtures. However, the on-site testing presents significant challenges. Thus, this study designs the wet-dry history to simulate the conditions experienced by asphalt mixture in the field, employing the asymmetric semi-circular bend (ASCB) test to determine the mixed fracture performance of asphalt mixture. The fracture criteria of the asphalt mixture before and after wet-dry cycling treatment were analyzed, and the propagation of crack mouth was measured using digital image correlation technology. Results indicate that wet-dry cycles lead to the mass loss in asphalt mixture, with higher loss correlating to more cycles. Wet-dry history causes an increase in the stress intensity factor at medium temperature. For the condition of 24 cycles, the low-temperature fracture toughness of mode I is significantly reduced, and the low-temperature fracture toughness increases under mixed and II modes, which results in an increased ratio of K_II/K_IC. The low-temperature fracture energy of asphalt mixture is susceptible to wet-dry history. Empirical fracture criteria such as linear model exhibit smaller deviation than the MTS and GMTS criteria. Wet-dry history notably reduces the low-temperature plastic deformation and diminishes the crack propagation deforming capability. The load-CMOD curve at low temperature is suggested to assess the impact of wet-dry history on the crack propagation capability of asphalt mixture.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104873"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418969","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 study on anchorage mechanical effect of rock bolts on cross-jointed rock mass using DIC and AE","authors":"Fei Xue ,&nbsp;Zhuoya Tong ,&nbsp;Wei Chen ,&nbsp;Tianzuo Wang ,&nbsp;Xiaobo You ,&nbsp;Zhongqin Lin","doi":"10.1016/j.tafmec.2025.104875","DOIUrl":"10.1016/j.tafmec.2025.104875","url":null,"abstract":"<div><div>Rock bolting is a commonly used reinforcement technique for jointed rock masses. This study investigates the anchorage effects of rock bolts on cross-jointed rock masses. Novel 3D-printed stainless steel bolts were used to reinforce rock-like specimens with main joint angles of 15°, 30°, 45°, 60°, and 75°. The integration of Acoustic Emission (AE) and Digital Image Correlation (DIC) techniques enabled comprehensive monitoring of crack propagation and strain evolution. The results show that bolt reinforcement significantly enhanced specimen strength (up to 79.9 %) and elastic modulus (up to 37.9 %) at smaller joint angles (≤45°). However, the reinforcement effectiveness diminished considerably at larger angles (≥60°), with strength reductions of up to 10.6 %. The combined AE-DIC analysis revealed distinct failure mechanisms: tensile-dominated failure at small joint angles and shear-dominated failure at larger joint angles. This study provides practical guidelines for optimizing rock bolt applications in jointed rock masses, particularly highlighting the need for alternative support strategies at large joint angles.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104875"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418966","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":"Translaminar fracture and shear properties of aluminum-mesh hybrid structures for high performance applications","authors":"Abdel-Halim Saber Salem Said ,&nbsp;A.M. Sadoun ,&nbsp;Amr Seif ,&nbsp;Mashhour A. Alazwari ,&nbsp;Waleed Mohammed Abdelfattah ,&nbsp;I.M.R. Najjar","doi":"10.1016/j.tafmec.2025.104874","DOIUrl":"10.1016/j.tafmec.2025.104874","url":null,"abstract":"<div><div>Incorporating metals with fiber enhances the efficiency and affordability of composite structures. Furthermore, metal reinforcement improves the material’s resistance to fracture by acting as crack arresters, closing cracks and preventing them from spreading. Thus, this study’s main goal is to conduct a comprehensive evaluation of the mechanical performance of hybrid structures incorporating glass fiber with aluminum mesh. Recognizing the critical role of fiber arrangement in determining the mechanical properties of laminated composites, hybrid specimens with Al-wire mesh positioned at the surface (GAL1) and at the core (GAL2), stacked with glass fibers embedded in epoxy resin, were fabricated using the hand lay-up method and compared to pure glass fiber-reinforced composite (PG). The results showed notable improvement: GAL1 enhanced fracture toughness by 6 % and shear strength by 29.95 % relative to PG, while also exhibiting better damage tolerance and absorbing energy under bearing loads with a strain increased by 5 %. Maximum compressive and ILS strength was attained by GAL2, which outperformed PG by 22.95 % and 31.71 %, respectively. Furthermore, it produced adequate load distribution but localized damaged surfaces. These results emphasize the promise of Al-mesh hybrid structures for robust, lightweight applications in structural and automotive sectors.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104874"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418970","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":"Determining Norton creep properties from small punch creep tests by using the representative stress–strain method and inverse approach","authors":"Li Xie ,&nbsp;Feng Yu ,&nbsp;Mingcheng Sun ,&nbsp;Yingzhi Li","doi":"10.1016/j.tafmec.2025.104876","DOIUrl":"10.1016/j.tafmec.2025.104876","url":null,"abstract":"<div><div>The small punch creep test (SPCT) emerges as an innovative technique for evaluating the creep properties of materials. Although the existing standards, such as CWA 15627 and EN 10371, establishes empirical correlations between SPCT and uniaxial creep tests (UCT), the complexity inherent to SPCT mandates an empirical approach that is both material-specific and labor-intensive for achieving precision. This paper introduces a novel methodology that synthesizes the representative stress–strain method with inverse finite element analysis to extract Norton creep properties of metallic materials directly from small punch test (SPT) and SPCT. The representative stress–strain method to SPT facilitates the determination of elasto-plastic properties at elevated temperatures, enabling a streamlined prediction of Norton creep law parameters by the inverse approach of SPCT. Notably, this methodology circumvents the need for intermediate UCT conversions, thereby providing a more efficient and accurate pathway for directly obtaining Norton creep properties from SPT and SPCT. Experimental validation conducted on P91 and P92NT steels at 600°C confirms a strong correlation between the predicted Norton creep properties and those obtained from UCT, underscoring the practicality and accuracy of the proposed approach.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104876"},"PeriodicalIF":5.0,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418971","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":"Potential fracture behaviors of a crack tip under mixed Mode-II/III loading","authors":"P.C. Chang ,&nbsp;Y.J. Xie","doi":"10.1016/j.tafmec.2025.104863","DOIUrl":"10.1016/j.tafmec.2025.104863","url":null,"abstract":"<div><div>Based on the three-dimensional geometrical modelling of multiple-crack initiations, present research demonstrates that there are four energy-based driving forces, which have different directions and different action regions or points around a crack tip under mixed Mode-II/III loading. These four energy-based driving forces compete to drive crack tip cracking and control the fracture configurations of the crack tip. By using the Griffith’s fracture criterion, when any one or two of the four energy-based driving forces reach the critical value of boundary cracking, a crack or two cracks will initiate in the form of crack kinking, symmetrical branching, side-branching or extension. There are multiple forms of the potential fracture configurations. The concerned fracture toughness and <em>K</em>-based fracture criterion for crack kinking and branching are found. The method to trigger crack branching is discussed. The notch effect on crack branching is investigated based on the present method.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104863"},"PeriodicalIF":5.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418968","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 numerical investigations on the synergistic effect of plasma nitriding and notch size on the fatigue properties of AISI 4140 steel","authors":"F. Yılan ,&nbsp;H. Kovacı","doi":"10.1016/j.tafmec.2025.104864","DOIUrl":"10.1016/j.tafmec.2025.104864","url":null,"abstract":"<div><div>Engineering structures across various sectors frequently experience fatigue damage under operational conditions, which significantly reduces their operational lifespan. Moreover, fatigue strength of the materials reduces when they have geometries such as notches and sharp corners because they constitute stress concentrations. On the other hand, different surface treatments can efficiently increase in managing the lifetime and performance of materials. In the current study, the fatigue properties of untreated and plasma nitrided notched steel samples were compared through numerical analyses and fatigue experiments. For this investigation, fatigue test specimens with different notch sizes made out of AISI 4140 steel were plasma nitrided at 460 °C and 535 °C for 9 h in a glow discharge environment. The specimens were analysed using XRD, SEM, and microhardness tester to ascertain their structural, morphological, and mechanical characterization. The notch fatigue behaviour of nitride samples was analysed numerically by the Finite Element Analysis (FEA). Furthermore, a rotational bending fatigue test system was utilized to conduct fatigue tests and consequently, fatigue date obtained from experimental results and FEA were compared. It was found that the thicknesses of compound layer and diffusion zone, compressive residual stresses, and hardness enhanced as the process temperature increased. Additionally, an increase of by up to 110 % was obtained in the notch fatigue resistance of the specimens under constant amplitude loading. According to the results obtained, it was observed that there were acceptable errors between the experimentally obtained values and the values obtained from the FEA. The results show that in all plasma nitrided notched samples, the fatigue crack initiation shifted towards the core and thus the fatigue strength increased, and especially at the increasing plasma nitriding process temperature, the R4 and R8 notch geometries exhibited better fatigue performance improvement than the other samples.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104864"},"PeriodicalIF":5.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143378030","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":"Higher-order asymptotic solution of bi-material V-notch with dissimilar hardening coefficients under plane strain condition","authors":"Zahra Nasiri,&nbsp;Mahdi Fakoor","doi":"10.1016/j.tafmec.2025.104872","DOIUrl":"10.1016/j.tafmec.2025.104872","url":null,"abstract":"<div><div>In this study, the first two terms of the asymptotic expansion of the stress field at the corner of the interface of two elastic–plastic materials with dissimilar hardening coefficients have been extracted under plane strain conditions. The total deformation theory of plasticity and hardening behavior in the form of power law has been used to obtain the general stress–strain relationship. The eigenvalue and mode-mix parameter related to the first term and the second term of the stress expansion according to the angle of the material that has a higher hardening coefficient have been extracted for different hardening coefficients. Considering the first two terms, unlike the first term where the eigenvalue is not dependent on the properties of the material with the lower hardening coefficient, the eigenvalue of the second term may depend on the properties of both materials. To obtain the coefficients of the first term and the second term of the stresses obtained from the asymptotic solution, the root mean square (RMS) of the differences between the stresses obtained from the asymptotic solution and the finite element (FE) solution are minimized in the shear loading condition. The conformity of the results obtained from the asymptotic solution with the results obtained from the FE solution at different angles and for different hardening coefficients has been checked. The obtained results show that with the increase of the angle and the hardening coefficient of the material which has a higher hardening coefficient, the discrepancy between the results of the asymptotic solution and the FE solution increases, and as a result, the need for higher order terms increases. The greater difference mode-mix parameter of the two materials causes a greater difference between the asymptotic results and the FE results in the first material, and this discrepancy is reduced by considering higher-order terms.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104872"},"PeriodicalIF":5.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386545","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 surface morphology characteristics study of marble containing randomly distribution fracture under 3D digital reconstruction","authors":"Dan Huang ,&nbsp;Zilong Xiao ,&nbsp;Qingping Jin ,&nbsp;Zheng Wu","doi":"10.1016/j.tafmec.2025.104870","DOIUrl":"10.1016/j.tafmec.2025.104870","url":null,"abstract":"<div><div>Fractured rocks, common in engineering materials, are significantly influenced by fissure distribution. This paper presents a series of experiments conducted to quantitatively evaluate the fracture surface morphology of marble specimens with different fracture network angles (30°, 45°, 60°, and 75°). Subsequently, the fracture surfaces of the failed specimens were digitally reconstructed from point cloud data obtained via three-dimensional (3D) laser scanning. A high-speed camera and scanning electron microscopy (SEM) were used to observe the rupture evolution and study the fracture micromorphology, respectively. The Joint Roughness Coefficient (JRC) quantitatively evaluated the two-dimensional morphology, while Skewness (S_sk), Kurtosis (S_ku), Interface Expansion Area Ratio (S_dr), and Maximum Volume Capacity (VMF) assessed the three-dimensional morphology of the fracture surface. A comparative analysis of two-dimensional and three-dimensional fracture surface morphology was conducted. The results indicate that the roughness of tensile crack is smaller than shear crack, the fractal dimension of tensile crack is smaller than shear crack. As the dip angle of prefabricated fractures increases, the primary failure mode of marble specimens transitions from tensile to mixed tensile and shear, and finally to shear failure. The JRC value for shear fracture surfaces exceeds that for tensile failure surfaces. Regression analysis revealed a high correlation between S_dr and JRC for both two-dimensional and three-dimensional fracture surface morphologies.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"137 ","pages":"Article 104870"},"PeriodicalIF":5.0,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143386546","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}