Engineering Fracture Mechanics最新文献_第7页

Fracture toughness of heat-treated SA508 steels predicted by instrumented spherical indentation test

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110766

Feng Yu , Ying Kan , Haiyan Zhang , Mingcheng Sun , Yingzhi Li

This paper presents a comprehensive analysis of the tensile properties and fracture toughness of five heat-treated SA508 steels, utilizing the instrumented spherical indentation test (ISIT). It critically examines the impact of microstructural variations induced by various heat treatment methodologies on these mechanical properties. A novel ISIT computational framework, IITv1.0, has been developed through enhancements to existing predictive algorithms, facilitating more accurate predictions of yield stress, strain hardening, tensile strength and fracture toughness. The IITv1.0 integrates an advanced critical fracture stress criterion alongside an enhanced energy release rate model, effectively differentiating between cleavage and ductile fracture modes resulting in SA508 steels from the five heat treatment processes. The study underscores the establishment of an automated selection criterion for differentiating the cleavage and ductile fracture modes of metallic materials. The predictive outcomes for tensile properties and fracture toughness by this IITv1.0 demonstrate strong concordance with experimental data obtained from the corresponding standard testing methods.

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引用次数: 0

Atomic scale analysis of cracking behavior at the triple junctions based on molecular dynamics simulations

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110762

Xiang Zhang , Puhao Li , Yaping Liu , Mengfei Zhang , Fan Yang

Triple junctions play important role in the deformation and fracture of polycrystalline metals. Due to the difference in the crystalline orientations of the composing grains, high stress concentration exists at the triple junctions, affecting the mechanical behavior of the materials. In order to explore the propagation behavior of an intergranular crack at the triple junctions, the evolutions of initially intergranular cracks at the triple junctions are investigated using a series of molecular dynamics simulations. The results show that the geometric parameters of triple junctions have important influences on the propagation mode of the initially intergranular crack. There exist four cracking modes, i.e., blunting, GB sliding, transgranular cracking, and intergranular cracking, among which the GB sliding mode has the best fracture resistance. Moreover, the triple junction geometry also has a strong effect on the crack propagation path and characters, resulting in distinctive ductile or brittle crack propagation characters. It is found that the crack propagation path gradually transits from intergranular cracking to transgranular cracking with the increase of grain boundary inclination angle from parallel to perpendicular with the crack. Also, the crack propagation character changes from ductile to brittle as the crystal orientation of the grain ahead of the crack gradually increases from 0 to 90 degrees. This work provides a unique insight for the understanding of fracture of nanocrystalline metals.

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引用次数: 0

Advanced computational models for accurate fracture toughness prediction in diverse concrete types: Insights from a robust laboratory database

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110757

Hanan Samadi , Arsalan Mahmoodzadeh , Mokhtar Mohammadi , Abdulaziz Alghamdi , Nejib Ghazouani , Mohd Ahmed

Fracture toughness (FT) is one of the most important material characteristics that determines the mechanical stability and operational performance of concrete structures, but its accurate measurement is rather difficult due to the complicated, expensive, and lengthy nature of the common experimental approaches. This study proposes a novel approach that combines machine learning (ML) with empirical information from three-point bending tests to estimate FT for a large set of concrete formulations. A dataset of 600 samples, which were carefully prepared and tested, containing aggregates of different sizes, water-cement ratios, curing conditions, and material additives, was used. Compared to other ML algorithms, the AD-XGBoost model achieved the best results by predicting FT with R² values of 0.99 and NRMSE of 0.0008. As per the sensitivity analyses, cement type, fiber percentage, and curing temperature were the most influential parameters on FT, while the inclusion of carbon and steel fibers into the concrete matrix enhanced its structural stability. Improvement of the toughness of concrete was also noticed with a prolonged curing process. Besides being an effective and reliable substitute for the prediction of the FT, this ML modelling strategy significantly minimizes the need for resource-demanding laboratory tests.

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引用次数: 0

New insights into interface characterization of ceramic matrix composites: Theory and application of hysteresis loops with Coulomb friction

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110758

Yong Ma , Xiaochuan Niu , Shu Guo , Lei Zhang , Jiaxuan Yan , Yuli Chen

To better predict the stress–strain relationship during unloading/reloading cycles in unidirectional fiber-reinforced ceramic matrix composites (FRCMCs), a comprehensive micromechanical hysteresis loop model is proposed, considering Coulomb friction and incorporating effects of interphase thickness, Poisson effect, residual thermal stress (RTS), and interfacial roughness. Based on the model, the hysteresis behavior is categorized into three distinct domains, i.e., small debonding energy (SDE), large debonding energy (LDE), and overlarge debonding energy (OLDE). For FRCMCs with low debonding toughness and thin interphase, the SDE scenario is more prevalent. By applying the model to interface characterization, we propose a more scientific set of parameters for interfacial performance description, including frictional coefficient, initial interfacial radial pressure, debonding toughness, and axial RTS. Furthermore, a method for obtaining the interfacial parameters based on tensile hysteresis tests is established, taking into account all the three domains. Especially, an innovative two-stage fitting approach is designed to derive interfacial properties for the SDE case, addressing the gaps in prior research. The comparison of the current model with experimental data for C_f/PyC/SiC and Nicalon/CAS composites demonstrates the reliability in hysteresis testing analysis.

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引用次数: 0

Bonding performance and load transfer characteristics of BFRP anchors: Insights from field pull-out tests

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110783

Hong Wei , Zhigang Tao , Zhigang Ma , Manchao He , Lin Tang , Honggang Wu

Basalt fiber-reinforced polymer (BFRP) anchors have been gradually employed in the field of geotechnical anchorage engineering. However, there remains substantial potential for further exploration of their bonding performance and load transfer characteristics through theoretical and experimental methods. In this study, five BFRP anchors with a diameter of 32 mm and varying lengths of 2.8 m, 3.3 m, 3.8 m, 4.3 m and 4.8 m, were employed to conduct field pull-out tests. Data on pull-out load, displacement, and stress was subsequently collected. The findings indicated a strong correlation between the calculated values of axial force and shear stress derived from the analytical solution of load transfer and the measured values (the correlation coefficient is greater than 0.9), thereby validating the effectiveness of the double exponential curve shear slip model. The load-bearing capacity of the anchoring system was affected by the critical anchorage length, which was computed to be 3.64 m. The form of load–displacement curve and the failure mode of the BFRP anchoring system were governed by the anchorage length. The morphology and types of cracks within the cement slurry were found to be associated with the tensile stress field. Although pre-reinforcement of weak strata can enhance the load-bearing capacity of the BFRP anchorage system, it is also imperative for manufacturers to enhance the shear performance of BFRP anchors by optimizing surface morphology design and refining manufacturing processes.

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引用次数: 0

Relationship between crack initiation stress and uniaxial compressive strength of brittle rocks

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110768

Baicun Yang , Chuyang Song , Yongting Duan , Zihan Zhao

Clarifying the reasonable value range of the stress threshold for brittle rock under uniaxial compression has high theoretical and practical significance for predicting the failure of an engineering rock mass. Although much attention has been directed toward the experimental investigation of the ratio of crack initiation stress to uniaxial compressive strength (CI/UCS) in recent years, the ratio’s reasonable value range has not be accurately obtained owing to the lack of relevant theoretical work. By combining renormalization group theory, a rock damage constitutive model, and a CI identification method, this study derived the theoretical expression of CI/UCS for brittle rock and calculated the reasonable value range of CI/UCS as 0.43–0.52. The value range of CI/UCS was verified by 8 experimental results obtained for Longmaxi shale with different bedding angles, and the results of previous experiments on 385 brittle rocks with different lithologies obtained from different locations. On this basis, the main factors affecting CI/UCS in brittle rocks were analyzed, and the applicability of the theoretical calculation results was discussed. The relevant research results are of great interest to theoretical research on the rock stress threshold and can be useful as guidelines in engineering practice.

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引用次数: 0

Localized necking predictions for an imperfect sheet using a porous plastic constitutive relation with two porosity parameters

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110711

I.A. Khan , A. Benallal , A.A. Benzerga , F. Moussy , A. Needleman

The role of void nucleation and void growth in triggering localized necking in biaxially stretched sheets is investigated using a rate independent porous plastic constitutive relation with two porosity parameters; one associated with the void volume fraction and the other associated with the weakening effect of void shape changes in shear dominated stress states. Proportional straining plane stress calculations are carried out for ratios of imposed in-plane principal strain rates ranging from

\approx - 1

(shear dominated) to 1 (equal biaxial tension). The framework for the localized necking calculations is that in which an imperfection band triggers the onset of localized necking as defined by a loss of ellipticity of the governing equations in the imperfection band. The imperfection band is taken to be either an increase in initial void volume fraction or an increase in the volume fraction of void nucleating particles. The predicted forming limit curves are compared with predictions for a localized necking bifurcation of a rigid-plastic solid. For negative values of the imposed strain ratio, except for near in-plane shear where the second porosity reduces the critical strains, the predicted critical localization strains and the predicted critical localization band orientations differ little from the corresponding critical values predicted by a rigid plastic bifurcation analysis. For biaxial tensile states the critical localization strains are sensitive to the nature and magnitude of the imperfection. When void nucleation occurs over a very narrow range of strain or stress, void nucleation and the onset of localized necking can coincide.

{"title":"Localized necking predictions for an imperfect sheet using a porous plastic constitutive relation with two porosity parameters","authors":"I.A. Khan , A. Benallal , A.A. Benzerga , F. Moussy , A. Needleman","doi":"10.1016/j.engfracmech.2024.110711","DOIUrl":"10.1016/j.engfracmech.2024.110711","url":null,"abstract":"<div><div>The role of void nucleation and void growth in triggering localized necking in biaxially stretched sheets is investigated using a rate independent porous plastic constitutive relation with two porosity parameters; one associated with the void volume fraction and the other associated with the weakening effect of void shape changes in shear dominated stress states. Proportional straining plane stress calculations are carried out for ratios of imposed in-plane principal strain rates ranging from <span><math><mrow><mo>≈</mo><mo>−</mo><mn>1</mn></mrow></math></span> (shear dominated) to 1 (equal biaxial tension). The framework for the localized necking calculations is that in which an imperfection band triggers the onset of localized necking as defined by a loss of ellipticity of the governing equations in the imperfection band. The imperfection band is taken to be either an increase in initial void volume fraction or an increase in the volume fraction of void nucleating particles. The predicted forming limit curves are compared with predictions for a localized necking bifurcation of a rigid-plastic solid. For negative values of the imposed strain ratio, except for near in-plane shear where the second porosity reduces the critical strains, the predicted critical localization strains and the predicted critical localization band orientations differ little from the corresponding critical values predicted by a rigid plastic bifurcation analysis. For biaxial tensile states the critical localization strains are sensitive to the nature and magnitude of the imperfection. When void nucleation occurs over a very narrow range of strain or stress, void nucleation and the onset of localized necking can coincide.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110711"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165257","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}

引用次数: 0

A nonlocal macro-meso-scale damage model based modeling for crack propagation in ferroelectric materials

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110712

Feng Xue, Jingyu Wang, Xiaozhou Xia, Xiaofan Gou

The accurate simulation of crack growth for ferroelectric materials plays a crucial role in the application of ferroelectric materials in electronic devices. In recent years, a nonlocal macro-meso-scale consistent damage (NMMD) model has been proposed for simulating the crack propagation in brittle materials, which offers the advantage of higher efficiency compared to the phase-field method. Different from the phase field method, this model does not need to solve the phase field equation at the same time. Therefore, the degree of freedom in solving can be reduced, thereby reducing the computational workload. In this paper, the authors proposed a new integration strategy for microscopic damage and devised a simple and efficient implementation of the NMMD model for the modelling of quasi-static fracture in the general purpose commercial software developer, COMSOL Multiphysics based on the finite element method (FEM) and studied the crack propagation for ferroelectric materials under the applied stress and electric fields. Different from the original NMMD model, only the tensile stress induced geometric damage is accounted for crack propagation by using the decomposition of elastic strain energy. The effects of different crack-face conditions, electrical boundary conditions and the electromechanical loading for crack growth of ferroelectric materials have been considered in our FEM simulation are discussed in this work.

{"title":"A nonlocal macro-meso-scale damage model based modeling for crack propagation in ferroelectric materials","authors":"Feng Xue, Jingyu Wang, Xiaozhou Xia, Xiaofan Gou","doi":"10.1016/j.engfracmech.2024.110712","DOIUrl":"10.1016/j.engfracmech.2024.110712","url":null,"abstract":"<div><div>The accurate simulation of crack growth for ferroelectric materials plays a crucial role in the application of ferroelectric materials in electronic devices. In recent years, a nonlocal macro-<em>meso</em>-scale consistent damage (NMMD) model has been proposed for simulating the crack propagation in brittle materials, which offers the advantage of higher efficiency compared to the phase-field method. Different from the phase field method, this model does not need to solve the phase field equation at the same time. Therefore, the degree of freedom in solving can be reduced, thereby reducing the computational workload. In this paper, the authors proposed a new integration strategy for microscopic damage and devised a simple and efficient implementation of the NMMD model for the modelling of quasi-static fracture in the general purpose commercial software developer, COMSOL Multiphysics based on the finite element method (FEM) and studied the crack propagation for ferroelectric materials under the applied stress and electric fields. Different from the original NMMD model, only the tensile stress induced geometric damage is accounted for crack propagation by using the decomposition of elastic strain energy. The effects of different crack-face conditions, electrical boundary conditions and the electromechanical loading for crack growth of ferroelectric materials have been considered in our FEM simulation are discussed in this work.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"314 ","pages":"Article 110712"},"PeriodicalIF":4.7,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165315","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}

引用次数: 0

Effect of microwave irradiation on the breaking and linear cutting of hard rock

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110729

Chuncheng Sun , Yixin Zhao , Yirui Gao , Sen Gao , Guangpei Zhu , Xiaodong Guo , Ronghuan Xie

Microwave technology, emerging as a novel approach to rock-breaking, holds significant promise in the realm of auxiliary mechanical pick rock breaking. In view of the problems existing in the hard rock breaking such as low efficiency and difficulty in one-time cutting, this study conducted experimental research using a method combining microwave irradiation and linear cutting with conical picks. The comprehensive temperature distribution of the rock is reproduced by 3D technology after microwave irradiation, defined the high-temperature zone and calculated the surface area. Moreover, analyzing the relationship between temperature and cutting force. And the effect of microwave-assisted conical pick rock breaking was quantified in terms of cutting force, cutting effect, and energy consumption. The results indicate that microwave irradiation induces heating in hard rock, leading to the formation of fissures and even partial fragmentation of rocks. The thermal damage effect of microwave is determined by the differences in the physical and mechanical properties of different rocks. In the experiment, basalt has the best heating effect and sandstone has the best fracturing effect. Compared to non-microwave, microwave (6 kW,60 s) irradiation reduces the cutting force, improves the effect of rock breaking, and reduces the work done (E) by the cutting force and the mechanical specific energy (MSE). Microwave irradiation-assisted mechanical rock breaking is better for sandstone, moderate for basalt, and inferior for granite in this study.

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引用次数: 0

Experimental study on the dynamic direct tensile fracture mechanism of thermally damaged sandstone

IF 4.7 2区工程技术 Q1 MECHANICS

Engineering Fracture Mechanics

Pub Date : 2025-02-07 DOI: 10.1016/j.engfracmech.2024.110728

Ming Li , Fuqiang Zhu , Ketong Wu , Hai Pu , Yanlong Chen , Jiazhi Zhang , Jishuo Deng

Understanding the dynamic tensile fracture mechanism of thermally damaged coal-rock media is crucial for developing scientific prevention and early warning systems in geotechnical engineering, particularly for high-temperature dynamic environments like underground coal gasification. This study employs a high-temperature loading system and a split Hopkinson tension bar (SHTB) experiment system to conduct dynamic direct tensile failure experiments on high-temperature thermally damaged coal sandstone. Three-dimensional cross-sectional scanners, scanning electron microscopy (SEM), and computed tomography are used to reveal the macroscopic and microscopic mechanisms of dynamic direct tensile fracture in thermally damaged coal sandstone. Experimental results show that temperature has a more significant effect on the macroscopic fracture characteristics of coal-rock media than impact velocity. As the impact velocity increases, the number of macroscopic debris gradually increases. However, the rise in temperature causes a deviation between the fracture plane normal and the tensile load direction and reduces the size of macroscopic debris. The macroscopic cross-sectional structural parameters of tensile failure exhibit an exponential change with increasing temperature and impact velocity. However, the change in cross-sectional structural parameters with temperature is significantly greater than with impact velocity. Additionally, the brittleness of the samples initially increases and then rapidly decreases with rising temperature, with the influence of high temperature on the rocks’ brittle-ductile properties gradually intensifies. The evolutionary pattern of microcracks and microporous defects within the coal-rock media shows that the formation and expansion of microcracks and the decoupling of mineral interfaces due to temperature significantly influence the rock’s physical and mechanical properties. At lower temperatures, the coal-rock media exhibits relatively smooth brittle fracture characteristics. However, under high-temperature conditions, the rock damage effect intensifies, and the cross-sectional morphological characteristics transition from brittle to ductile, exhibiting more complex and rough fracture forms. The increase in impact velocity mainly affects the undulation and roughness characteristics of the cross-sectional structure. The impact velocity has a lesser effect on the morphological characteristics of the coal-rock media’s cross-section at a certain temperature.

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引用次数: 0