Theoretical and Applied Fracture Mechanics最新文献

{"title":"Study on the dynamic fracture law of layered materials under the explosive load of slotted charge","authors":"Zhongwen Yue ,&nbsp;Xu Wang ,&nbsp;Xingyuan Zhou ,&nbsp;Huang Wang ,&nbsp;Shengnan Xu ,&nbsp;Meng Ren ,&nbsp;Linzhi Peng","doi":"10.1016/j.tafmec.2025.104932","DOIUrl":"10.1016/j.tafmec.2025.104932","url":null,"abstract":"<div><div>Directional fracture blasting with slotted charge is one of the main rock breaking methods for excavating layered rock mass tunnels. This article uses dynamic photoelastic method combined with high-speed photography technology to visualize the process of explosive stress waves and explosive cracks passing through vertical layers of different strengths caused by the explosion of slotted charge. The dynamic fracture law of layered materials with different strength layers under slotted charge explosion loads was studied. The results indicate that the greater the strength of the bedding plane, the more significant the waveform changes of the explosive stress wave when transmitted through the bedding plane. When the strength of the bedding is relatively high, the crack velocity is less affected by the bedding. When the strength of the bedding is weak and there is a significant difference from the strength of the specimen material, the velocity of the crack after passing through the bedding will undergo severe oscillations. Before the main crack reaches the bedding plane and after passing through it, the fracture mode of the crack is mainly mode-I. During the process of the crack passing through the bedding plane, the dynamic crack transforms from the mode-I crack to the mixed mode crack. Under the premise of a certain crack velocity, bedding angle, and physical and mechanical parameters of the specimen, the propagation trajectory of the crack passing through the bedding is related to the difference in bedding strength and specimen strength.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104932"},"PeriodicalIF":5.0,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642513","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 the evolution of rock fractures induced by rolled static cracking agents in steeply inclined hard faults","authors":"Lei Sun,&nbsp;Chong Li,&nbsp;Yue Cao,&nbsp;Zhijun Xu,&nbsp;Lianhai Tai,&nbsp;Huan Xia,&nbsp;MengHu Sun,&nbsp;Menglong Zha,&nbsp;ShuaiShuai Jiang","doi":"10.1016/j.tafmec.2025.104927","DOIUrl":"10.1016/j.tafmec.2025.104927","url":null,"abstract":"<div><div>The static blasting method is the preferred approach for addressing hard faults within an inclined working face. The presence of shear stress within the inclined rock layers can significantly affect the cracking efficiency of the Rolled Static Cracking Agent(RSCA). To study the rupture damage characteristics of rocks under the expansion of RSCA with different shear stress magnitudes, a novel Compression Shear Coupling Test system (CSCT) was employed. Fracture tests were conducted on RSCA specimens at six different inclination angles (0°, 5°, 10°, 15°, 20°, and 25°) under constant pressure. Acoustic emission monitoring and full-field strain measurement were employed to analyze the dynamic fracture process and damage characteristics of the specimens. The results indicate that an increase in inclination accelerates the crack initiation efficiency of RSCA, causing cracks to propagate at lower expansion pressures. The magnitude of the shear stress component significantly affects the fracturing characteristics of the specimens; as the inclination increases, the proportion of shear cracks in the specimens increases significantly. Additionally, the AE energy, fractal dimension, and surface density of cracks initially decrease and then increase. The distribution of surface strain concentration areas is closely related to the inclination angle, with shear stress causing the maximum tensile stress point to shift towards the shear direction of the specimen, forming strip-shaped damage zones. As a key factor affecting rock fracturing, the shear stress component alters the crack propagation pattern during RSCA fracturing. The research results provide data support and theoretical reference for field applications.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104927"},"PeriodicalIF":5.0,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636855","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 residual stress on sulfide stress cracking and fracture toughness in carbon steel: A phase-field modeling approach","authors":"Alok Negi ,&nbsp;Imad Barsoum","doi":"10.1016/j.tafmec.2025.104911","DOIUrl":"10.1016/j.tafmec.2025.104911","url":null,"abstract":"<div><div>The susceptibility of OCTG-grade alloys to sulfide stress cracking (SSC) in hydrogen sulfide (H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>S)-rich sour environments poses a unique challenge for downhole oil and gas exploration, particularly when considering the role of residual stresses. These stresses, inherent in materials from fabrication processes, can strongly influence their cracking resistance even in the absence of external loads. This study numerically examines the effect of residual stresses on the fracture toughness (<span><math><msub><mrow><mi>K</mi></mrow><mrow><mi>ISSC</mi></mrow></msub></math></span>) measurements associated with SSC resistance of a high-strength low-alloy carbon steel C110 in H<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>S-containing aqueous test solution using industry-standard single-edge notched tension (SENT) and double-cantilever beam (DCB) testing methodologies. Residual stresses are measured on pipe samples and are incorporated into the finite element model of the pipe through a thermo-mechanical equivalent loading. The residual stress field is then mapped onto the fracture mechanics test specimens to represent the initial stress distributions. A coupled deformation-diffusion phase-field framework is implemented in COMSOL to simulate crack propagation under the combined influence of residual stress and environmental factors. The results offer insights into SSC mechanisms, demonstrating that elevated residual stress levels in both SENT and DCB tests affect SSC initiation thresholds and arrest, signifying reduced fracture toughness and increased susceptibility to SSC. This study underscores the importance of considering residual stresses in fracture-mechanics-based SSC integrity assessments to improve the reliability of components in sour service applications.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104911"},"PeriodicalIF":5.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644928","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":"Mechanical behavior and damage constitutive model of fractured granite after high-temperature treatment based on 3D digital image correlation","authors":"Lan Zeng ,&nbsp;Jialong Zhang ,&nbsp;Shi Liu","doi":"10.1016/j.tafmec.2025.104919","DOIUrl":"10.1016/j.tafmec.2025.104919","url":null,"abstract":"<div><div>A high-temperature environment, cracks, and surface pressure of the rock affect the deep mining of rock masses and nuclear waste disposal. We used the Muskhelishvili theory of fracture mechanics to deduce the fracture stress intensity K of granite samples affected by compressive stress, fractures, and gas–vapor pressure. We established a high-temperature damage constitutive model based on the Burr distribution with an effective stress invariant and the Hoek-Brown (H-B) criterion. Uniaxial mechanical loading and axial compression tests were conducted on granite samples with prefabricated cracks after different high-temperature treatments. Three-dimensional digital image correlation (3D-DIC) was used to analyze the mechanical behavior and strain localization of the fractured rock samples affected by temperature and stress. The results showed that the elastic modulus reached the maximum at the largest inclination angle at different heat treatment temperatures. The surface principal strain increased uniformly before the stress–strain peak, strain localization increased, and the macroscopic cracks in the post-peak region expanded rapidly at different temperatures. The dominant failure mechanism of the granite samples was tensile shear failure at different temperatures and fracture angles. The strain data obtained by placing virtual extenders in different positions and directions on the rock surface are in good agreement with the experimental data. The predicted results of the high-temperature damage constitutive model aligned well with the experimental results, indicating the model accurately predicted the evolution of axial compression fracture of heat-damaged fractured rock. The results provide new insights into the instability mechanism of rock masses in different environments.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104919"},"PeriodicalIF":5.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628547","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 hold time and force ratio on creep fatigue crack growth (CFCG) behaviour of P91 weldments at 600 °C","authors":"Challa Krishna Teja ,&nbsp;G.R. Kiranchand ,&nbsp;Chitresh Chandra ,&nbsp;M. Nani Babu ,&nbsp;N. Narasaiah","doi":"10.1016/j.tafmec.2025.104929","DOIUrl":"10.1016/j.tafmec.2025.104929","url":null,"abstract":"<div><div>Modified 9Cr-1Mo steel is the chosen material for the construction of thermal and mechanical stress-bearing structures in fossil fuel-fired power plants, aiming for greater operational efficiency, extended life, and a considerable reduction in greenhouse gas emissions. The detailed study of welded joints and their properties, along with the underlying reasons and mechanisms for failure propagation, is crucial for quality control. Hence, there is a need to study the creep fatigue crack growth behaviour (CFCG) of P91 weldments and to evaluate the consequences and the underlying mechanisms behind crack propagation. This article intends to provide a preliminary comparison of the behaviour of welded P91 compact tension C(T) samples with those of the base metal. CFCG of P91 welded specimens have been performed at 600 °C for a force ratio of 0.1, 0.5 and 0.8 with hold times of 10, 60 and 600 s. The test results were compared with corresponding tests for base metal samples. The variation in cyclic crack growth rate has been evaluated with respect to stress intensity factor range <em>(</em>Δ<em>K)</em> and <em>(C_t)_avg</em> parameter and correlated with the variation in hardness corresponding to the change in microstructural features across the welded joint. The phenomenon of crack tunnelling has been evaluated along with detailed fractography of the tested samples. The angular distortion of the terminal crack front is subdued for the welded samples. The welded samples can thus be said to exhibit a higher degree of resistance to lateral deformation due to the advent of triaxial stresses.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104929"},"PeriodicalIF":5.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143644926","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":"Design of a novel bonded-SENB specimen for determining the pure modes and the mixed-mode cohesive fracture energies in brittle and quasi-brittle adhesives","authors":"Ghazaal Talebi Sanami ,&nbsp;Jamal Bidadi ,&nbsp;Mohammad Reza Gheibi ,&nbsp;Hamed Saeidi Googarchin","doi":"10.1016/j.tafmec.2025.104924","DOIUrl":"10.1016/j.tafmec.2025.104924","url":null,"abstract":"<div><div>Integrating fracture and damage mechanics with numerical methods in commercial software is essential for predicting the failure of structural adhesive joints. These joints often face complex loading conditions and fracture in a mixed-mode (tensile/shear) manner. Understanding the fracture energy of the adhesive in all loading conditions is crucial and requires precise measurement methods. While various laboratory specimens with different shapes and loading configurations have been proposed to study cracking behavior and fracture energy under pure modes or mixed-mode loading, some have practical limitations. This research introduces a new test configuration, bonded-SENB, for measuring the full range of fracture energies in brittle and quasi-brittle adhesive joints. This specimen is easy to prepare and test. A data reduction scheme based on the contour integral framework in ABAQUS is employed to investigate the effects of crack length and loading span on the fracture parameters. The fracture envelopes from this specimen are compared with results from conventional methods like double-cantilever beam (DCB) and end-notched flexure (ENF) tests, yielding strong agreement with standard fracture energy measurements.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104924"},"PeriodicalIF":5.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628546","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":"Improved double-phase-field algorithm based on scaled boundary finite element method for rock-like materials","authors":"Yue Zhuo,&nbsp;Degao Zou,&nbsp;Kai Chen,&nbsp;Yongqian Qu,&nbsp;Guoyang Yi,&nbsp;Shanlin Tian","doi":"10.1016/j.tafmec.2025.104916","DOIUrl":"10.1016/j.tafmec.2025.104916","url":null,"abstract":"<div><div>The study of cracking analysis algorithms for rock-like materials is an important branch in the development of solid mechanics, and the related results have received extensive attention from researchers around the world. To broaden the generalizability of the phase-field method, an improved double-phase-field (DPF) algorithm based on the Scaled Boundary Finite Element Method (SBFEM) is presented. Firstly, the main governing equations are deduced and interpreted based on the nonlinear SBFEM framework. Secondly, the flexible polygon class library, data structure and solving framework for DPFM are designed by object-oriented programming. Subsequently, the presented algorithm is integrated in the self-developed finite element software GEODYNA. Thirdly, the precision is demonstrated by three classic examples, and its efficiency and practicality for complex mixed-mode fractures are validated with three case studies. Obviously, the tensile and compressive-shear mixed-mode fracture mode can be reproduced realistically, and the efficient quadtree grids can be utilized directly, making the efficiency to be optimized by more than 75% in representative cases. More potential for practical applications would be further elucidated with extending the proposed method to three-dimensional.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104916"},"PeriodicalIF":5.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143636856","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 discontinuity on failure and acoustic emission behavior of rockburst in hard rock under deep ground","authors":"Linfei Wang ,&nbsp;Shiying Han ,&nbsp;Jun Peng ,&nbsp;Chuanhua Xu ,&nbsp;Kun Pan","doi":"10.1016/j.tafmec.2025.104923","DOIUrl":"10.1016/j.tafmec.2025.104923","url":null,"abstract":"<div><div>In the field of underground engineering, rockburst disaster is often associated with the discontinuous plane within rock mass. The discontinuity resided in rock has an important influence on the performance of rockburst. However, the mechanism of discontinuous plane-related rockburst remains unclearly understood. This study experimentally investigates the influence of structural plane on rockburst evolution using true triaxial tests on sandstone specimens with a circular through-hole. Acoustic emissions (AE) techniques are employed to analyze micro-cracking behavior during rock failure. Results show that structural plane induces an asymmetric rockburst pattern in hole sidewalls, with large-sized plate-like and fine-grained fragments constituting 68.1% and 13% in volume for discontinuous specimens, respectively. AE data indicate that specimen with a structural plane reach crack initiation earlier, exhibiting higher AE activity and an earlier onset of rockburst. The failure is a tensile-shear mixed mode, with a shear ratio of 19.1%. The structural plane also delays rockburst precursor response, showing a lower precursor response coefficient (PRC). The results in this study improve our understanding in mechanism of structural plane-related rockburst.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104923"},"PeriodicalIF":5.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620328","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 ultrasonic rolling on crack growth behavior of TC4 titanium alloy laser weld under overload condition","authors":"Gao Jiayuan ,&nbsp;Cong Jiahui ,&nbsp;Zhou Song ,&nbsp;Zhang Zhichao ,&nbsp;Gao Shoulong ,&nbsp;Liu Zhuo","doi":"10.1016/j.tafmec.2025.104910","DOIUrl":"10.1016/j.tafmec.2025.104910","url":null,"abstract":"<div><div>In this study, the effect of ultrasonic rolling on the crack propagation behavior of TC4 titanium alloy laser weld under overload conditions was investigated through experiments and finite element simulation. The research content included the analysis of the cross-sectional microstructure, residual stress, microhardness, fatigue properties and fatigue fracture of the specimens before and after ultrasonic rolling strengthening. The results show that ultrasonic rolling forms a highly dislocated plastic deformation layer on the surface of the specimen, which alleviates the instantaneous damage caused by overload and introduces cold work hardening at the overload line. In terms of fatigue life, the life of the Original-OL specimen is 10.75% longer than that of the Original specimen, while the life of the USRP-OL specimen is 55.86% longer than that of the USRP specimen. Finite element analysis shows that after overloading, an overload residual compressive stress cloud will form at the crack tip, which will reduce the stress intensity factor during crack propagation. As the overload rate increases, the minimum stress intensity factor decreases and the overload inhibition area expands. And the stress intensity factor caused by overload residual stress is much higher than the stress intensity factor of ultrasonic rolling residual stress. The study proposed a strengthening mechanism combining ultrasonic rolling strengthening with overload conditions, indicating that surface strengthening and overload changed the residual stress distribution at the crack tip, enhanced the overload delay effect, and improved the fatigue life of the specimen.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104910"},"PeriodicalIF":5.0,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143577448","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":"The master curve methodology at elevated loading rates: A detailed interlaboratory study","authors":"Johannes Tlatlik ,&nbsp;Uwe Mayer ,&nbsp;Enrico Lucon ,&nbsp;Jan Džugan","doi":"10.1016/j.tafmec.2025.104917","DOIUrl":"10.1016/j.tafmec.2025.104917","url":null,"abstract":"<div><div>The Master Curve Methodology (ASTM E1921) provides an experimental approach to assess a material’s temperature-dependent fracture toughness, generally under quasi-static loading rates. For handling elevated loading rates, guidelines are outlined in annex A1 of ASTM E1921 and annex A14 of ASTM E1820. It has been observed in the literature, however, that the Master Curve concept can fail to adequately assess fracture behavior for elevated loading rates. Specifically, experimental data suggest that the shape factor p = 0.019 /°C and threshold K_min increase, and the implied Weibull distribution for K_Jc values can be unsuitable for elevated loading rates up to <span><math><mrow><mover><mi>K</mi><mo>̇</mo></mover></mrow></math></span> = 10⁵ MPa√m/s. The aim of this paper is to address this topic with an interlaboratory study, allowing a systematic analysis of precision and accuracy of the methodology for moderately elevated loading rates of <span><math><mrow><mover><mi>K</mi><mo>̇</mo></mover></mrow></math></span> = 10³ MPa√m/s. The work includes the participation of 6 labs with 3 materials (22NiMoCr3-7 or A508 Grade 2, its weld, and a high-strength steel, S690QL1) with 2 specimen types (C(T) and SE(B) specimens). The 22NiMoCr3-7 steel and its weld were additionally tested with small SE(B)10x10 specimens (pre-cracked Charpy).</div><div>The following results and conclusions were made. The Master Curve methodology works well for homogeneous materials, such as the RPV steel base metal at moderately elevated loading rates. The scatter between individual labs lies within the expected standard deviation of 10 °C. Testing is recommended near T₀ in order to avoid the effect of heat generation and crack arrest, which can affect T₀. For S690SL1, the Master Curve methodology appears adequate for moderate loading rates despite an observed influence of extraction location. The RPV steel weld can be adequately described by the inhomogeneity analysis of the Master Curve. The requirements for data sampling in ASTM E1820 A14 appear conservative. A violation does not strongly impact T₀. Liquid cooling mediums should be avoided for testing at elevated loading rates due to possible inertia effects of the clip gauge. The use of larger specimens appears advisable, since they allow a more reproducible cleavage fracture assessment, even for homogeneous materials.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"138 ","pages":"Article 104917"},"PeriodicalIF":5.0,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592149","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}