Theoretical and Applied Fracture Mechanics最新文献

{"title":"Study on the dynamic mode I fracture characteristics of granite after different thermal-cold cycle","authors":"Lu Chen ,&nbsp;Yuhao Xia ,&nbsp;Qiuhong Wu ,&nbsp;Ling Zeng","doi":"10.1016/j.tafmec.2025.105050","DOIUrl":"10.1016/j.tafmec.2025.105050","url":null,"abstract":"<div><div>Geothermal reservoir rocks undergo cyclic thermo-mechanical loading during EGS operations, where progressive damage accumulation and fracture network development directly dictate system performance and longevity. In order to investigate the dynamic fracture characteristics of granite under the action of thermal-cold cycles, dynamic fracture tests are carried out on the central straight crack semi-circular disc (NSCB) granite specimens treated with multiple thermal-cold cycles (maximum number of cycles 13 times) at 400 °C, and the crack expansion rate is monitored. Based on the digital image correlation (DIC) method, the impact of thermal and cold cycling effect on the fracture process zone (FPZ) is studied, and the morphological characteristics of the fracture surface are analyzed. The effect of cyclic treatment on the microstructure of granite is investigated using scanning electron microscopy (SEM). The results show that the dynamic fracture properties of granite are significantly degraded under the action of repeated hot and cold cycles. When the number of hot and cold cycles reaches more than 10 times, the decrease is more than 28.7 %. The fracture process zone of granite begins to develop gradually from the crack tip. The length of the fracture process zone increases first and then decreases with the increase of load, and the maximum value is 9.2 mm. The dynamic fracture toughness, the maximum length of FPZ and the average crack growth rate decrease exponentially with the increase of the number of thermal cycles. The fracture surface fractal dimension is negatively correlated with dynamic fracture toughness, suggesting that the decrease of fracture resistance promotes the generation of rougher fracture surfaces. Macroscopic damage trajectories indicate that thermal cracking is the main factor controlling the theory expansion path. The combined effects of high-temperature heating damage, fast cooling, thermal-cold cycles, and water weakness are responsible for the deterioration of granite damage.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105050"},"PeriodicalIF":5.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321917","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 true triaxial compression mechanical behavior of fissured granite and its micro-fracture mechanism based on the grain-based model","authors":"Xiang-Xi Meng ,&nbsp;Sheng-Qi Yang ,&nbsp;Yu Song ,&nbsp;Zhen Zhong ,&nbsp;Xiao-Shuang Li ,&nbsp;Yan-Hua Huang","doi":"10.1016/j.tafmec.2025.105051","DOIUrl":"10.1016/j.tafmec.2025.105051","url":null,"abstract":"<div><div>Understanding the mechanical properties and rupture mechanism of fissured rocks under true triaxial stress conditions is of great significance in guiding engineering practice and preventing geo-engineering disasters. In this study, the mechanical properties, deformation characteristics, and damage mechanisms of prefabricated fissured granite were investigated by laboratory true triaxial experiments and grain-based model (GBM) simulations. Granite specimens with seven different fissure geometries (rock bridge inclination and length and fissure inclination) were tested in true triaxial compression tests. As a complementary study, the mineral composition and microstructure of granite were modeled using GBM numerical simulations for purpose of analyze the evolution of microfractures. The obtained results indicate that, larger rock bridge inclination, smaller rock bridge length, and larger crack inclination decreased the peak strength (up to 76.31 %), damage threshold, and modulus of elasticity of the specimens. Based on the specific configuration of the fissures, the pattern of damage underwent a transformation. It shifted from tensile shear cracks to a type of mixed tensile-shear cracks where the tensile cracks were predominant, and these cracks fully traversed the rock bridge region. Acoustic emission (AE) analysis shows that the fissured samples exhibit earlier and more intense energy release due to accelerated microcrack formation and propagation, and this effect is more pronounced at larger rock bridge inclinations, smaller rock bridge lengths, and larger rift inclinations. Numerical simulations validate the ability of GBM to capture macroscopic deformation and failure modes, showing strong agreement with the experimental stress-strain response (the peak stress deviation &lt; 4.04 %). The microcrack evolution analysis emphasizes that cracks mainly start at the fissure tip and that the rock bridge geometry has a key influence on the propagation trajectory. In addition, the intermediate principal stress (<span><math><msub><mi>σ</mi><mn>2</mn></msub></math></span>) enhances the peak strength but weakens as the effect of cracking increases, especially at larger rock bridge inclinations or smaller fissure angles. This exploration offers new insights of view on the micromechanical fracture mechanism of cleft granite under complex stress states, and provides theoretical and practical guidance for the stability assessment of deep underground engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105051"},"PeriodicalIF":5.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321918","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 influence of steam engines on designing against fatigue and fracture","authors":"M.N. James","doi":"10.1016/j.tafmec.2025.105046","DOIUrl":"10.1016/j.tafmec.2025.105046","url":null,"abstract":"<div><div>This paper discusses the role that steam engines and, in particular, steam locomotives played in the early thinking about fatigue and fracture and in the development of manufacturing standards for pressure vessels and boilers. It will consider the historical context of railway failures and how understanding of them increased over time, while highlighting the important role that mechanical engineers played in the development of knowledge regarding the failures. It will also discuss the formation of technical societies intended to promote better design using codified standards and maintenance. It concludes by observing that the ongoing development of high speed railways offers new structural integrity and materials challenges, and opportunities to a another generation of engineers. The paper is also intended to record some of the contributions made by Professor Rod Smith to railway structural integrity and his high regard for steam traction.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105046"},"PeriodicalIF":5.0,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144365607","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":"Crack propagation mechanism of fissured sandstone subjected to uniaxial cyclic compression test","authors":"Guoshao Su ,&nbsp;Jinwen Huang ,&nbsp;Youneng Liu","doi":"10.1016/j.tafmec.2025.105049","DOIUrl":"10.1016/j.tafmec.2025.105049","url":null,"abstract":"<div><div>The cracking behavior of fissured rock under cyclic loading plays a pivotal role in determining the dynamic stability of deep underground structures. This study investigates the macrocracking behavior of fissured red sandstone through uniaxial static and cyclic compression tests. The sandstone specimens, shaped as thin rectangular prisms (75 mm × 150 mm × 30 mm), contained centrally prefabricated goose-shaped fissures. The macroscopic and microscopic fracture characteristics of fissured sandstone were studied and analyzed by using multi-source monitoring methods (stress, strain, AE, DIC) and discrete element numerical simulation (PFC). The results reveal distinct differences in crack propagation characteristics between the static and cyclic loading tests. DIC observations indicate that compared to the static loading test, the relative normal and tangential displacements on both sides of the anti-wing crack under cyclic loading test increased by 123.4 % and 178.2 %, respectively. Besides, crack initiating mode under cyclic loading were identified using the Relative Displacement Measurement (RDM) method. Furthermore, PFC simulations demonstrate that cyclic loading significantly increased the probability density of force chains in the anti-wing crack directions ([40°–80°] and [100°–140°]), while the force chain probability in the wing crack direction ([80°, 100°]) decreased. These changes influenced normal stress levels and the generation of tensile microcracks between particles in the cracking expanding path. Overall, cyclic loading resulted in more pronounced macroscopic secondary cracking, severe shear spalling, and greater damage to the specimens compared to static loading.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105049"},"PeriodicalIF":5.0,"publicationDate":"2025-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330516","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 investigation and numerical simulation analysis of non-penetrating spatial crack propagation and coalescence behaviors","authors":"Jun Xu ,&nbsp;Sen Luo ,&nbsp;Shihe Sun ,&nbsp;Baijian Wu","doi":"10.1016/j.tafmec.2025.105048","DOIUrl":"10.1016/j.tafmec.2025.105048","url":null,"abstract":"<div><div>This study employs a comprehensive approach integrating experimental analysis and numerical simulation to systematically examine the propagation characteristics of non-penetrating spatial cracks during rock fracturing processes. The results reveal significant differences between the propagation modes of non-penetrating and penetrating cracks. Surface observations demonstrate that anti-wing cracks, as a typical three-dimensional propagation feature, although not necessarily initiating from pre-existing crack tips, predominantly propagate along the loading direction and frequently coalesce with wing cracks to induce localized surface spalling. Internal analysis indicates that crack inclination angle critically influences adjacent crack paths: when the angle between cracks and loading direction increases, micro-cracks preferentially nucleate at edge regions, which subsequently affects both crack propagation behavior and specimen strength. The wrapping effect of wing cracks governs the internal-external connection sequence of adjacent cracks, creating discontinuous propagation patterns through self-inhibition mechanisms until crack coalescence occurs. Peak strength analysis shows a non-monotonic relationship with inclination angles, exhibiting fluctuations at 15° and 45° before reaching maximum values at 90°. Notably, wrapping phenomena persist universally across specimens (including surface-cracked specimens) except at 0° and 90° inclinations, confirming their prevalence in rock fracture processes. Under these special inclination conditions, newly formed cracks exhibit distinct directional propagation characteristics. These findings elucidate the three-dimensional evolution mechanisms of non-penetrating spatial cracks and establish a theoretical foundation for fracture prediction in rock engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105048"},"PeriodicalIF":5.0,"publicationDate":"2025-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321888","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":"Numerical study of the effect of residual stresses on fracture toughness in the microstructure of ZrO2 ceramics","authors":"G. Lasko ,&nbsp;I. Danilenko ,&nbsp;U. Weber ,&nbsp;S. Schmauder ,&nbsp;S. Farahifar","doi":"10.1016/j.tafmec.2025.105047","DOIUrl":"10.1016/j.tafmec.2025.105047","url":null,"abstract":"<div><div>This study investigates the influence of residual stresses on crack propagation in the microstructure of zirconium ceramics using the element elimination technique (EET) within the finite element method (FEM) framework. The effect of grain size distribution, morphology, and phase distribution are examined. The crack resistance is evaluated for two representative microstructures of zirconia ceramics, considering the role of residual stresses in the constitutive phases. The analysis is conducted under both uniaxial tension and three-point bending conditions.</div><div>Results indicate that under tensile loading, residual stresses reduce the maximum sustainable load and, consequently, decrease crack resistance by approximately 30%. In contrast, under three-point bending, residual stresses enhance the crack resistance. The computational modeling results are validated through experimental testing of sintered ceramic samples with a similar grain structure in 3-point bending. The strong agreement between numerical and experimental results confirms the accuracy of the proposed model and highlights the significant role of residual stresses in determining the mechanical properties of zirconia ceramics.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105047"},"PeriodicalIF":5.0,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144321916","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":"Research on local cyclic plastic behavior and fatigue life prediction of notched components based on digital image correlation","authors":"Xun Zhao,&nbsp;Jian Li,&nbsp;Tao Sun,&nbsp;Shan-Shan Wang,&nbsp;Han Deng,&nbsp;Jian-Guo Zhu,&nbsp;Jun Xia","doi":"10.1016/j.tafmec.2025.105045","DOIUrl":"10.1016/j.tafmec.2025.105045","url":null,"abstract":"<div><div>In this study, the digital image correlation (DIC) method was utilized to monitor the evolution of the strain at the notch root as the number of cycles progresses. The influences of notch type, notch size, and external load (load amplitude <em>F</em>_a, load ratio <em>R</em>) on the evolution of the strain at the notch root and the ratcheting strain rate were investigated. Considering the evolution of the ratcheting strain rate at the notch root, a fatigue life prediction model applicable to notched components with different notch sizes and under different load conditions was developed in terms of the stress concentration factor, the notch nominal stress amplitude, and the load ratio. Compared with the results of the Coffin − Manson model for predicting low − cycle fatigue life using the half − life strain amplitude, most of the predicted values of the proposed model in this paper are within the 1.5 times error band, with the maximum not exceeding the 1.75 times error band, while most of the predicted values of the Coffin − Manson model exceed the 2 times error band. The results indicate that the method in this paper has better prediction accuracy. Additionally, the mean square deviation values of the prediction results of the prediction model considering notch size, load amplitude, and load ratio are reduced by 0.02826, 0.04776, and 0.0424 respectively. The proposed method has certain reference significance for the fatigue analysis of notched components.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105045"},"PeriodicalIF":5.0,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144364364","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 the interaction mechanisms between fissures and layers of SCB specimens using a novel layer 3D printing technology and DEM","authors":"Qiang Zhang ,&nbsp;Shuyang Yu ,&nbsp;Jun Yu ,&nbsp;Yifei Li ,&nbsp;Hesi Xu ,&nbsp;Qingfu Huang","doi":"10.1016/j.tafmec.2025.105044","DOIUrl":"10.1016/j.tafmec.2025.105044","url":null,"abstract":"<div><div>Layered rock masses are widely distributed, and their unique structures affect engineering stability. Hence, it is important to conduct research on layered rock fracture mechanisms. This study aims to explore the interaction mechanisms between bedding and fissures. A layered rock sand 3D printing molding process is proposed to prepare Semi-Circular Bending (SCB) specimens containing bedding and pre-fabricated fissures. Crack propagation tests under three-point bending loads are carried out, and the strain distribution is obtained by combining with DIC technique. The PFC2D software is used for numerical simulation. Results show that the bedding inclination angle <em>β</em> and pre-fabricated fissure inclination angle <em>α</em> significantly influence the mechanical behavior and peak strength of SCB specimens: variations in <em>β</em> (0° − 90°) result in differing complexities of crack propagation paths (e.g., the most tortuous path at <em>β</em> = 30°), with peak strength first increasing then decreasing (maximum at <em>β</em> = 30°), while changes in <em>α</em> (15° − 75°) cause peak strength to first decrease then increase (minimum at α = 30° and 45°), collectively revealing the relationship between bedding-aligned crack extension mechanisms and strength evolution. The location of tensile stress concentration guide the crack propagation. The angle and relative position between the fissure and the bedding are the key factors determining the crack propagation path and the specimen failure mode. The preparation method of the bedding rock mass structure by sand 3D printing proposed can effectively simulate the characteristics of natural bedding planes, providing a new approach for the study of the fracture mechanics of layered rock masses. By combining experiments and numerical simulations, the interaction mechanism between bedding planes and fissures is deeply analyzed, and the research results have important reference value for the stability analysis and design of rock engineering.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105044"},"PeriodicalIF":5.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253758","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 determination of double-K fracture parameters for self-compacting concrete with waste tire rubber and silica fume","authors":"Robert Bušić,&nbsp;Goran Gazić,&nbsp;Ivica Guljaš,&nbsp;Ivana Miličević","doi":"10.1016/j.tafmec.2025.105021","DOIUrl":"10.1016/j.tafmec.2025.105021","url":null,"abstract":"<div><div>In order to address environmental issues caused by the large amount of waste tire rubber, which is often deposited uncontrollably, its use in concrete, by replacing a portion of natural aggregates with waste rubber particles, seems to be an effective approach. At the same time, it must be noted that such an action will likely change many of its mechanical parameters, as well as the fracture and cracking behavior of self-compacting concrete. With that in mind, mechanical and fracture properties of self-compacting concrete with crumb rubber and silica fume were investigated in this study. A total of 14 self-compacting concrete mixtures were prepared with constant water to binder ratio of 0.4 and a cement content of 450 kg/m³. Chemical admixtures were used to maintain the desirable fresh properties of self-compacting concrete and to achieve adequate aggregate distribution during casting of the test samples. The experimental program focused on determining the fracture toughness of self-compacting rubberized concrete (SCRC). Fracture properties were determined using the wedge splitting test (WST) as an alternative to three-point bending test (3PBT) and were subsequently described using the double K-fracture model. Test results also indicated that mixtures containing up to 15 % of crumb rubber yielded satisfactory results for both initial and unstable fracture behavior. Up to the 15 % replacement level, K_Ic,ini remains approximately equal to the reference value, with a maximum reduction of 16 %. Considering fracture process, the addition of rubber alters the fracture mechanism of SCC from brittle/quasi-plastic to quasi-plastic. In addition, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to analyze the interfacial transition zone (ITZ). Microstructural analysis confirmed that the effect of silica fume on improving interfacial bonding with crumb rubber is limited due to the inherent chemical incompatibility and hydrophobic nature of rubber particles.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105021"},"PeriodicalIF":5.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272199","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":"Hydrogen embrittlement susceptibility of 301 metastable austenitic stainless steel","authors":"Ehsan Norouzi ,&nbsp;Reza Miresmaeili ,&nbsp;Hamid Reza Shahverdi ,&nbsp;Mohsen Askari-Paykani ,&nbsp;Laura Maria Vergani","doi":"10.1016/j.tafmec.2025.105043","DOIUrl":"10.1016/j.tafmec.2025.105043","url":null,"abstract":"<div><div>The influence of hydrogen on the mechanical properties and embrittlement behavior of 301 metastable austenitic stainless steel was studied. The hydrogen embrittlement (HE) was studied using in situ tensile testing under electrochemical hydrogen charging at various current densities. The results showed that the Portevin-Le-Chatelier (PLC) phenomenon occurred in the uncharged sample, whereas serration disappeared after hydrogen charging due to the hydrogen enhanced decohesion mechanism (HEDE) and the presence of α′ martensite. Hydrogen charging at current density of 10 and 30 mA/cm² resulted in a 7 and 19 % loss in yield strength and a 77 and 80 % loss of elongation, respectively. The fracture toughness of uncharged and H pre-charged specimens was determined by the indentation technique and the results showed a 35 % decrease in fracture toughness after hydrogen charging. Evaluation of the microstructure by electron backscatter diffraction (EBSD) showed that the dislocation density increased in the presence of hydrogen. In addition, a reduction in stacking fault energy (SFE) by hydrogen resulted in the formation of more α′ martensite in the microstructure, compared to uncharged sample at the same level of deformation.</div></div>","PeriodicalId":22879,"journal":{"name":"Theoretical and Applied Fracture Mechanics","volume":"139 ","pages":"Article 105043"},"PeriodicalIF":5.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144308002","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}