Engineering Fracture Mechanics最新文献

{"title":"Influence of axial prestress and loading rate on dynamic fracture of pre-faulted granite","authors":"Haifan Xiao ,&nbsp;Guiyun Gao ,&nbsp;Ying Xu ,&nbsp;Pu Wang ,&nbsp;Ningyu Wu ,&nbsp;Xiaopan Huang","doi":"10.1016/j.engfracmech.2025.111535","DOIUrl":"10.1016/j.engfracmech.2025.111535","url":null,"abstract":"<div><div>Understanding the interplay between axial prestress and dynamic loading rate is critical for elucidating dynamic rupture mechanisms in pre-faulted rock masses, with direct implications for earthquake nucleation and underground engineering stability. This study investigates the dynamic fracture responses of granite specimens containing pre-existing faults with joint angles of 20° and 25°, subjected to axial prestress ranging from 0 to 6 MPa and loading rates between 195 and 1437 GPa/s. An improved split Hopkinson pressure bar (SHPB) system integrated with ultrahigh-speed camera and digital image correlation (DIC) technique was employed to capture real-time fracture evolution, energy dissipation, and slip dynamics. The results reveal that both axial prestress and loading rate substantially regulate dynamic strength, rupture mode, and energy absorption. Notably, peak energy absorption occurs at an intermediate prestress level (4 MPa), while elevated prestress (6 MPa) suppresses slip rate and enhances rupture stability. With increasing loading rate, fracture transitions from tensile-dominated to mixed shear-tensile failure. The findings highlight the nonlinear coupling effects of prestress and strain rate on rupture dynamics, offering new insights into fault activation mechanisms under combined static-dynamic loading conditions.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111535"},"PeriodicalIF":5.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145046439","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 mechanics-based modeling of time-varying mesh stiffness for spiral bevel gears with spatial crack propagation","authors":"Shuai Mo ,&nbsp;Daixin Bai ,&nbsp;Yaxin Li ,&nbsp;Bowei Yao ,&nbsp;Sujiao Chen ,&nbsp;Yurong Huang ,&nbsp;Wenai Shi ,&nbsp;Nanjiang Peng ,&nbsp;Guoliang Liu ,&nbsp;Haruo Houjoh ,&nbsp;Wei Zhang","doi":"10.1016/j.engfracmech.2025.111537","DOIUrl":"10.1016/j.engfracmech.2025.111537","url":null,"abstract":"<div><div>Spiral bevel gears (SBGs), as critical components in aerospace transmissions, are highly susceptible to crack initiation under heavy-load conditions, which markedly reduces mesh stiffness. This study proposes an innovative analytical framework that merges gear meshing theory with fracture mechanics, transcending the limitations of traditional plane-strain assumptions. First, an accurate conjugate tooth-surface model is constructed on the basis of tool motion derived from meshing theory, and tooth-contact analysis (TCA) is employed to reveal the meshing trajectories and contact characteristics of the gear pair. Second, a coupled slice-potential energy method is introduced to define a pinion crack model for cracks propagating along the tooth width; the model is parameterized by crack depth, crack length, and the angle between the crack and the outer surface, and time-varying mesh stiffness (TVMS) models for both healthy and cracked SBGs are established to uncover the differential effects of varying crack parameters on TVMS degradation. The regulatory laws governing changes in structural parameters-initial meshing phase angle, pitch cone angle, and face cone angle-on contact trajectories, load distribution, and mesh stiffness are systematically analyzed, and the advantages of the proposed method over traditional stress-based approaches are highlighted. Finally, the reliability of the fault stiffness calculation model is verified through finite-element validation and experiments on a cracked-SBG test rig using time-domain and frequency-domain features, providing a theoretical basis for early crack fault diagnosis based on stiffness monitoring.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111537"},"PeriodicalIF":5.3,"publicationDate":"2025-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020069","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":"Dynamic fracture evolution and energy dissipation mechanisms in geothermally exposed shotcrete under high-velocity impact","authors":"Xixin Zhang ,&nbsp;Lianjun Chen ,&nbsp;Hailei Kou ,&nbsp;Guoming Liu ,&nbsp;Zhaotun An","doi":"10.1016/j.engfracmech.2025.111528","DOIUrl":"10.1016/j.engfracmech.2025.111528","url":null,"abstract":"<div><div>To investigate the dynamic mechanical properties of underground shotcrete under high-temperature conditions, dynamic compression experiments were conducted using a φ50 mm split Hopkinson pressure bar (SHPB) system integrated with a heating apparatus. A high-speed camera captured the impact-induced dynamic fracture evolution, enabling detailed analysis of specimens with varying damage severities. Results demonstrate that the dynamic compressive strength of shotcrete exhibits a positive correlation with strain rate but decreases with rising temperature. Four distinct failure modes were identified: intact, crack propagation, block separation, and structural disintegration. Each distinct failure mode observed experimentally corresponds to a specific stress–strain curve. The failure process corresponds to a specific point on the stress–strain curve. The study further examined stress–strain response characteristics and energy dissipation mechanisms during failure. Two predictive models were developed: one establishing the relationship between energy dissipation rate and dynamic compressive strength, and another correlating temperature with particle fineness modulus. The dynamic performance test results of shotcrete were used to independently validate the two models. These models advance the understanding of shotcrete behavior under coupled thermo-mechanical degradation, providing a theoretical framework for analyzing energy transfer and stress evolution during impact events.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111528"},"PeriodicalIF":5.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020070","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 “collusion” mechanism of blast-Induced cracks under initial compressive stress","authors":"Chen Huang ,&nbsp;Zhe Sui ,&nbsp;Liyun Yang ,&nbsp;Lang Liu ,&nbsp;Zong-Xian Zhang ,&nbsp;Huanzhen Xie ,&nbsp;Siyu Chen","doi":"10.1016/j.engfracmech.2025.111533","DOIUrl":"10.1016/j.engfracmech.2025.111533","url":null,"abstract":"<div><div>Initial compressive stress has a significant impact on the “collusion” of blast-induced cracks. This study uses a dynamic caustics experimental system to conduct blasting experiments on parallel collinear and non-collinear defects, aiming to explore the effects of initial compressive stress and defect spacing on the propagation and interaction of blast-induced cracks, and to reveal the “collusion” mechanism of blast-induced cracks between parallel double defects under initial compressive stress. The research results show that the promoting effect of initial compressive stress on crack propagation and the suppressing effect of “collusion” of blast-induced cracks on crack propagation exhibit different strengths at different defect spacings. However, initial compressive stress can increase the stress intensity factor (SIFs) and propagation velocity of the main crack during its initiation and propagation process, suppressing the mutual repulsion of the “collusion” crack tips and making the “collusion” between blast-induced cracks more tightly bound. As the defect spacing increases, the promoting effect of initial compressive stress gradually dominates, becoming more significant than the suppressing effect of crack “collusion.” In addition, numerical simulations were used to study the evolution of the full-field stress under the action of blasting stress waves and double defects, and to analyze the stress-time curves at the defect tips.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111533"},"PeriodicalIF":5.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144997239","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":"Unified rock strength theory incorporating holistic consideration of macro-meso-micro defect coupling effects","authors":"Shi Hao ,&nbsp;Chen Wenlong ,&nbsp;Wu Jiangyu ,&nbsp;Rong Chuanxin ,&nbsp;Wang Zhenshuo ,&nbsp;Song lei ,&nbsp;Feng Jihao ,&nbsp;Zhang Houquan ,&nbsp;Wei Di","doi":"10.1016/j.engfracmech.2025.111534","DOIUrl":"10.1016/j.engfracmech.2025.111534","url":null,"abstract":"<div><div>The establishment of a unified rock strength theory under multi-scale defect coupling effects is beneficial for engineering disaster prevention. This paper first develops a microscopic damage analytical model for rocks based on the Weibull distribution of damage probability on element strength. Subsequently, by analyzing the co-deformation effect of rock matrix and fracture structures, and incorporating the fracture number and the power-law distribution indices (PDI) of the fracture length, a macro-meso damage analytical model is constructed. Building upon this foundation and combined with Lemaitre’s strain equivalence principle, a unified rock strength theory under multi-scale defect coupling effects is established. The strength of specimens under multi-scale defect coupling effects was simulated using Particle Flow Code (PFC^2D) to verify the proposed theory. The main results are as follows: (1) As the homogeneity coefficient increases, the element strength distribution demonstrates a significant convergence process, with both dispersion degree and distribution range gradually narrowing, while the corresponding uniaxial compressive strength (UCS) shows a decelerating growth trend. (2) The decrease of PDI corresponds to increased proportion of long fractures, weakened rock homogeneity, and enhanced damage degree. With increasing fracture quantity and decreasing PDI, UCS generally follows a decelerated reduction pattern after initial acceleration. (3) The flow law of specimen UCS under multi-damage parameters was obtained based on the unified strength theory. Fracture quantity exhibits relatively linear influence on specimen UCS, while smaller values of homogeneity coefficient and PDI demonstrate more significant weakening effects. (4) The unified strength theory results show high consistency with numerical simulations, achieving a correlation coefficient of 0.990, proving the theory’s effectiveness in describing the coupled influence of element strength and fracture distribution characteristics on rock UCS. (5) The proposed strength theory overcomes existing limitations that separately consider fracture angle or length and demonstrates stronger capability in reflecting both factors’ impacts on specimen strength.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111534"},"PeriodicalIF":5.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020068","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":"Dynamic structural response of thin conical shells during drop impact and related load characteristics","authors":"Ke Lin ,&nbsp;Shuai Wang ,&nbsp;Jicheng Li ,&nbsp;Ming Qu ,&nbsp;Yixia Yan ,&nbsp;Gang Chen ,&nbsp;Qingping Zhang ,&nbsp;Liang Xiang","doi":"10.1016/j.engfracmech.2025.111525","DOIUrl":"10.1016/j.engfracmech.2025.111525","url":null,"abstract":"<div><div>To study the deformation and failure modes of thin conical shells during drop impact and related load characteristics derived from the structural response of conical shells, the dynamic structural response of thin conical shells during drop impact and related load characteristics are investigated in the present manuscript, integrated with the numerical simulation and the stress wave analysis. The deformation and failure morphologies of thin conical shells, as well as the acceleration history of components mounted on its upper end will be emphasized, and the influences of several factors, including drop height, structural mass, and support frame rigidity, etc., are also discussed in detail. Related results demonstrate that in the drop impact condition, damage and failure in the thin conical shell mainly initiates in the region near the inner surface at its bottom end, then the whole bottom part separates from the shell, and cracks propagate gradually along with the drop progress, finally petal-like fragments are formed and they further fold inward progressively. The deformation and failure process of thin conical shell significantly affects the acceleration characteristics of components mounted on the upper end. The reflection and superposition of impact stress wave within the conical shell, support frame, and component structure dominate the overall load characteristics. The drop height and structural mass contribute significantly to the deformation and failure morphologies of conical shell and then the acceleration history of the key component, higher drop height will result in higher degree of deformation and longer deformation duration, and then lead to the increase in the amplitude and width of the acceleration pulse; similarly, larger structural mass will also induce higher width of acceleration pulse, but it results in a reduced acceleration amplitude. Moreover, due to the vibration of the support frame during the drop process, a certain vibration feature occurs in the acceleration curve of the key component, and the vibration frequency is the same as the elastic vibration frequency of support frame structure. Related work is beneficial in providing theoretical guidance for the structural design of load generators based on thin conical shells.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111525"},"PeriodicalIF":5.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989092","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":"Failure behavior and fracture toughness of Brazilian disc ice specimens with pre-flaws in compression","authors":"Xiaobin Li ,&nbsp;Fangchen Huang ,&nbsp;Yiheng Zhang ,&nbsp;Ying Tang ,&nbsp;Pengcheng Hu ,&nbsp;Wei Chen ,&nbsp;Qing Wang ,&nbsp;Duanfeng Han","doi":"10.1016/j.engfracmech.2025.111527","DOIUrl":"10.1016/j.engfracmech.2025.111527","url":null,"abstract":"<div><div>Understanding the crack propagation mechanism of ice with flaws is of great significance in many ice engineering applications. The failure behavior and fracture toughness of Brazilian disc ice specimens with pre-flaws are experimentally investigated under quasi-static loading. A series of repeated tests are conducted to explore the load-bearing characteristics and damage evolutions of single and double flawed ice specimens with various inclination angles from 0° to 75°. Experimental results indicate that the peak loads of both single and double flawed specimens have a non-monotonic trend, first decreasing and then increasing with increasing inclination angles. The peak loads of double flawed specimens were consistently lower than those of single flawed specimens. Ice samples exhibit significant brittle failure characteristics, with the load–displacement curve rapidly decreasing after the peak load. For the single flawed specimens, those with an inclination angle of ≥ 15°are dominated by wing cracks, while those with an inclination angle of 0° appear the tensile-shear mixed-mode fracturing. The pre-existing flaws in double flawed specimens are prone to coalescence by wing tensile cracks in the bridging zone, and the cracks in the upper region transition from shear to tensile mode. The evolution of deformation field is preliminarily analyzed, and the characteristics of crack initiation are explored based on digital image correlation technology. The generalized maximum tangential stress (GMTS) criterion was employed to conduct the mixed-mode fracture toughness analysis on Brazilian disc ice specimens with single flaw. GMTS criterion provides substantially closer predictions of mixed mode fracture toughness for the experimental results. These results improve the understanding of the crack propagation and failure modes in the ice with initial defects.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111527"},"PeriodicalIF":5.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933167","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":"Structural tuning of single-lap joints with thin-walled inserts and nanomodified adhesives for superior flexural performance","authors":"Salih Akpinar ,&nbsp;Murat Kilbas ,&nbsp;Murat Demiral","doi":"10.1016/j.engfracmech.2025.111529","DOIUrl":"10.1016/j.engfracmech.2025.111529","url":null,"abstract":"<div><div>This study investigates the enhancement of bending performance in single-lap joints (SLJs) through the integration of thin-walled metallic inserts and nanostructure-reinforced adhesives. The experimental and numerical work focused on evaluating the influence of carboxyl-functionalized carbon nanotubes (CNT-COOH) added to a structural epoxy adhesive (DP460), as well as the role of thin-walled AA2024-T3 aluminum alloy and carbon fiber fabric reinforced composite inserts embedded within the joint’s overlap region. The bonded adherends were also fabricated from AA2024-T3 aluminum alloy, a commonly used material in lightweight structural applications. Insert lengths were varied systematically (25, 22, 19, 16, 13, and 10 mm) to assess their contribution to load transfer efficiency under four-point bending. While the addition of 1 wt% CNT-COOH alone enhanced the joint’s maximum bending moment by around 10 %, its impact became far more pronounced when used with reinforcement inserts. Specifically, thin-walled aluminum inserts boosted the moment capacity by up to 93.1 %, and composite inserts led to even greater improvements—reaching as high as 128.1 %. The combination of CNT-COOH-enhanced adhesive and strategically placed thin-walled inserts delivered the highest structural gains. A finite element model was developed to investigate failure mechanisms, revealing that the buckling behavior and flexural stiffness of the thin-walled inserts significantly influenced joint performance.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111529"},"PeriodicalIF":5.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145004764","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":"A simplified calibration method for Chaboche model based on monotonic loading curves","authors":"Deyu Kong ,&nbsp;Dejian Meng ,&nbsp;Yunkai Gao ,&nbsp;James Yang","doi":"10.1016/j.engfracmech.2025.111509","DOIUrl":"10.1016/j.engfracmech.2025.111509","url":null,"abstract":"<div><div>The Chaboche mixed isotropic/kinematic hardening model has garnered widespread applications due to its efficacy in characterizing the stress–strain behavior of materials subjected to multi-axial cyclic loading. However, the calibration of the Chaboche model material parameters poses significant challenges, necessitating at least one cyclic loading test to procure experimental data. This process can be both time-consuming and economically burdensome. To address these challenges, this paper proposes an efficient and accurate calibration method based on monotonic loading curves, applicable to existing alloys exhibiting hysteretic curves similar to monotonic loading curves. This method employs reduction coefficients to derive stable hysteresis characteristics from monotonic loading data directly and extract the Chaboche model parameters. Validation through cyclic three-point bending tests confirms that this method simplifies the calibration process while maintaining high accuracy.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111509"},"PeriodicalIF":5.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144989090","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 growth in cracked-lap-shear specimens with multidirectional composite adherends under quasi-static loading","authors":"Koichi Hasegawa ,&nbsp;Keiji Arai ,&nbsp;Hisaya Katoh ,&nbsp;Tetsuya Morimoto","doi":"10.1016/j.engfracmech.2025.111506","DOIUrl":"10.1016/j.engfracmech.2025.111506","url":null,"abstract":"<div><div>Quasi-static crack growth behaviour involving crack migration into composite adherends was investigated using cracked-lap-shear specimens. The baseline specimen configuration consisted of quasi-isotropic carbon/epoxy laminates providing 45° ply at the adhesive/adherend interface. Extensive use of ex-situ X-ray CT imaging together with supplemental FE analysis enabled description of three-dimensional discrete cracking mechanisms simultaneously growing at multiple sites including the bondline, the 45° ply of the strap adherend next to the adhesive, and the interfaces between the ply and its adjacent 0°　ply. Specimens with different interface plies were tested to study their effects on crack migration, which highlighted extensive evolution of cracks and delaminations in multiple layers of the strap adherend for the specimens with 90° ply at the interface. Further, the influence of a fabric carrier in the adhesive and testing environments was separately examined for the baseline specimen configuration. While crack types observed were basically the same, the timing for their formation, the significance as well as the ease of their extension were seen to be largely varied among the test conditions, affecting the resistance to unstable growth of the delamination at the 45°/0° ply interface of the strap. The detailed three-dimensional crack migration behaviour of the bonded composite joint and its dependence on adhesive material, layup and environments revealed by the present work provides insights towards more robust joint design or material improvement which can prevent unpredicted/unstable crack growth.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111506"},"PeriodicalIF":5.3,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145020067","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}