Mechanics of Time-Dependent Materials最新文献

{"title":"Dynamic analysis of a viscoelastic composite spherical shell","authors":"YaJuan Chen,&nbsp;Ziheng Zhai,&nbsp;Jiayi Hao","doi":"10.1007/s11043-025-09821-9","DOIUrl":"10.1007/s11043-025-09821-9","url":null,"abstract":"<div><p>The nonlinear dynamic problem of an incompressible viscoelastic composite spherical shell under sudden constant loading on its inner and outer surfaces was studied. A mathematical model was established in this paper. Starting from the fundamental equations, the viscoelastic constitutive equation was expressed in the form of Stieltjes convolution. The governing equations for the displacement function were derived, and general solutions for displacement and stress expressions in the Laplace domain were obtained using Laplace transforms. The displacement and stress distributions were then solved via inverse Laplace transforms. Additionally, the variation rules of stress and displacement inside the spherical shell with increasing internal/external pressures and geometric parameters of the composite shell were discussed.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis on the detonation characteristics and determination of Jones-Wilkins-Lee(JWL)-Miller parameters of detonation products for aluminized nitrate ester plasticized polyether (NEPE) propellant","authors":"Zongtao Guo,&nbsp;Xiong Chen,&nbsp;Jiaming Liu,&nbsp;Jinsheng Xu,&nbsp;Xinyu Cao,&nbsp;Zhengwei Sun","doi":"10.1007/s11043-025-09817-5","DOIUrl":"10.1007/s11043-025-09817-5","url":null,"abstract":"<div><p>The nitrate ester plasticized polyether (NEPE) solid propellant incorporates three principal high-energy components: cyclotetramethylene tetranitramine (HMX), ammonium perchlorate (AP), and aluminum powder (Al), sharing compositional similarities with aluminized explosives. To characterize the detonation response and establish the equation of state (EOS) parameters for detonation products, two <span>(Phi )</span>50 mm cylinder tests were conducted on NEPE propellant. The radial expansion displacement-time profiles were derived through continuous monitoring of electric probes arrays, which measured the radial displacement differential induced by detonation products. The experimental results demonstrate close agreement between the two datasets, indicating that the electric probes methodology achieves measurement accuracy and exhibits excellent repeatability. A calibration method of Jones–Wilkins–Lee (JWL)-Miller EOS parameters of propellant detonation products considering the reaction of aluminum powder based on cylinder test data, Genetic Algorithm and numerical simulation was proposed. The calibrated JWL-Miller EOS parameters acquired through this methodology demonstrate enhanced fidelity in reproducing the copper cylinder expansion processes.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145028405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Viscous dissipation and thermo-diffusion effects on time-dependent MHD heat propagative nanofluid flux across vertical movable permeable plate with thermal radiation","authors":"B. Prabhakar Reddy,&nbsp;Jumanne Mng’ang’a,&nbsp;J. M. Sunzu","doi":"10.1007/s11043-025-09818-4","DOIUrl":"10.1007/s11043-025-09818-4","url":null,"abstract":"<div><p>This work focuses on the assessment of the viscous dissipation and thermo-diffusion facets on buoyancy-driven heat-propagative unsteady magnetized flow of water based nanofluids (Cu-H₂O and TiO₂-H₂O) from a vertical moving penetrable channel with chemical reaction in the incidence of thermal radiation. Due to their excellent heat transfer properties, considered two different nanoparticles Cu and TiO₂ in this prevalent investigation and water as the base liquid. Non-dimensional variables are exploited to convert the structured dimensional partial derivative model for the flow fields into non-dimensional PDEs, which are subsequently solved using the computational scheme of semi-implicit finite difference. The convergence and stability test were performed to confirm the precision of the results. The work involved a detailed study of flow parameters and their ranges, including Eckert number <span>(0.1 le Ec le 0.4)</span>, Soret number <span>(0.1 le Sr le 0.4)</span>, nanoparticle volume fraction <span>(0.01 le varphi le 0.04)</span>, heat source parameter <span>(0.5 le Hs le 3.0)</span>, and radiation parameter <span>(1.0 le N le 4.0)</span>. Relevant results on how the emerging parameters influence the flow fields as well the skin friction, temperature and mass gradients are explained in a tabular and graphical mode. The ultimate results visibly exposed for both nanofluids that the temperature and flow velocity significantly abridged by high Prandtl numbers and radiation, but amplified by viscous heating and heat source development of both fields. Increased thermo-diffusion stimulated to intensify the flow speed and species concentration, but both fields compressed by the chemical reaction. The temperature of both nanofluids boosted by the addition of nanoparticles to the base fluid, while the fluid flow velocity decreased. The skin-friction for both nanofluids raised by heat source and viscosity, but it was diminished by the magnetic field and chemical reactions. Heat transfer rate raised-up at plate surface for both nanofluids by heat source, radiation and viscous heating. Remarkably, when dissolving <span>(4%)</span> of Cu nanoparticles into the water, heat transfer rate improved to <span>(7.1%)</span> but when dispersing the same amount of TiO₂ nanoparticles into the water, heat transfer raised-up rate to <span>(8.7% )</span>. Further, the flow fields are superior for TiO₂-H₂O nanofluid, because of their hydrodynamic interaction properties compared to Cu-H₂O nanofluid.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145011965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of time-dependent mechanical degradation in coal roofs using a strain softening constitutive model","authors":"Sonu Saran,&nbsp;Prudhvi Raju Gadepaka,&nbsp;Ashok Jaiswal","doi":"10.1007/s11043-025-09820-w","DOIUrl":"10.1007/s11043-025-09820-w","url":null,"abstract":"<div><p>A time-dependent Hoek-Brown strain-softening constitutive model was developed for underground coal-roof rock masses. The basic strain-softening model requires strength parameters (<span>(m)</span> and <span>(s)</span>) as functions of plastic strain and time. It is important to note that the material exhibits yielding before reaching peak strength at the crack/yield initiation point. The yielded elements show time-dependent (creep) behavior. During this process, the strength parameters decrease over time. Keeping this in mind, a mathematical exponential expression has been developed to estimate the peak strength parameter over time, considering an additional peak reduction parameter. The peak strength parameter at zero time is referred to as the ultimate peak strength parameter. The constitutive model comprises two sets of strength parameters: peak strength parameters (<span>(m_{rm})</span> and <span>(s_{rm})</span>), residual parameters (<span>(m_{mathit{rmt}})</span> and <span>(s_{mathit{rmt}})</span>), and the peak reduction parameter (<span>(beta )</span>). Deducing these parameters is practically impossible in the laboratory for large-scale coal masses. Therefore, instances of immediate failure, short-term stability, and long-term stability in field cases are used to deduce the strength parameters through a back analysis technique. In total, 34 Indian coal mine cases have been considered for assessing these parameters. The numerical models for all cases have been developed by incorporating the material properties, in-situ stress, and boundary conditions. This research introduces a novel method that employs numerical simulations using a viscoelastic-plastic model to capture the time-dependent behavior of rock, including the gradual reduction of its strength. The findings offer key insights into time-dependent roof rock behavior, supporting advanced stability strategies and collapse risk reduction.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving stab resistance of soft body armor composites via modified shear thickening fluids (STFs)","authors":"Tao Hai,&nbsp;Fahad Mohammed Alhomayani,&nbsp;Pradeep Kumar Singh,&nbsp;Naglaa F. Soliman,&nbsp;Walid El-Shafai,&nbsp;Abuzar Es’haghi Oskui","doi":"10.1007/s11043-025-09815-7","DOIUrl":"10.1007/s11043-025-09815-7","url":null,"abstract":"<div><p>This study examined shear thickening fluids (STFs) for soft armor composites. STFs, consisting of 55 wt.% silica nanoparticles in polyethylene glycol (PEG), have been used to boost the quasi-static and dynamic stab resistance of E-glass fabrics. To enhance the rheological properties of virgin STF (VSTF), we introduced modifications to the PEG chain structure through interactions with malonic and tartaric acid, resulting in the creation of MSTF and TSTF, respectively. Rheological analysis demonstrated that these modifications led to a substantial increase in viscosity, with MSTF and TSTF exhibiting approximately 25.92 and 5.92 times greater viscosity than VSTF, respectively. A series of quasi-static knife stab tests was conducted, revealing a significant improvement in peak force. Moreover, as stab loading speed increased, the energy absorption capacity of the materials demonstrated a direct correlation. Subsequently, we employed regression analysis with artificial intelligence techniques to predict knife stab resistance across various loading speeds. Our results established a robust relationship between force-displacement characteristics and knifing speed. Notably, the heightened viscosity of fabrics infused with TSTF, MSTF, and VSTF led to dynamic impact energy absorption values that were 1.74, 1.58, and 1.43 times higher, respectively, compared to the neat fabric.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145011613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-dependent electromechanical analysis of composite piezoelectric panels on concrete auxetic foundations: a mathematical model validated by a machine learning algorithm","authors":"Huijing Duan,&nbsp;Jialing Li,&nbsp;Belgacem Bouallegue","doi":"10.1007/s11043-025-09813-9","DOIUrl":"10.1007/s11043-025-09813-9","url":null,"abstract":"<div><p>This study presents a comprehensive time-dependent electromechanical analysis of functionally graded piezoelectric (FGP) composite panels resting on concrete auxetic foundations, subjected to aerodynamic flow. The investigation integrates advanced theoretical, numerical, and machine learning methodologies to capture the coupled behavior of smart structures under transient loading. A refined higher-order shear deformation theory (HSDT) is employed to model the mechanical behavior of the FGP panel, ensuring an accurate representation of through-thickness deformation without requiring shear correction factors. The electromechanical coupling is governed by Maxwell’s equations, while Hamilton’s principle is utilized to derive the governing equations of motion. To discretize and solve the resulting time-dependent partial differential equations efficiently, a differential quadrature hierarchical finite element method (DQHFEM) is proposed, in conjunction with the Gauss-Lobatto-Legendre (GLL) quadrature rule to ensure numerical stability and precision. The effect of the auxetic foundation, characterized by negative Poisson’s ratio behavior, is incorporated through a modified elastic foundation model. Aerodynamic loads are modeled using first-order piston theory. To validate the proposed mathematical model and verify its predictive capabilities, a deep neural networks (DNN) is trained on simulation data, showing high accuracy in capturing nonlinear time-dependent responses. Parametric studies are conducted to examine the influence of material gradation, aerodynamic intensity, and foundation characteristics on the dynamic response. The results demonstrate the robustness and accuracy of the proposed framework, suggesting its potential for optimizing smart composite structures in aeronautical and civil engineering applications under complex loading environments.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144990544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of pre-annealing temperature on the microstructure and corrosion behavior of Ni88.6-Cr11.4 alloy for biomedical applications","authors":"Irfan Liaquat,&nbsp;Warda Mushtaq,&nbsp;Abdul Munam Khan,&nbsp;Tehmina Bashir,&nbsp;Uzma Zahoor","doi":"10.1007/s11043-025-09819-3","DOIUrl":"10.1007/s11043-025-09819-3","url":null,"abstract":"<div><p>Nickel–chromium (Ni–Cr) alloys offer high strength, wear resistance, shape-memory effect, and broad clinical applications. This study evaluates the effect of pre-annealing on their electrochemical corrosion behavior. Samples were annealed at 500 °C and 700 °C and compared with a non-annealed reference. Microstructure and composition were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX), while corrosion behavior was examined by open-circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). Annealing at 500 °C and 700 °C resulted in lattice expansion (from 3.551 Å to 3.561 Å) and a reduction in crystallite size (from 9.40 nm to 8.10 nm), accompanied by chemical inhomogeneity leading to degradation of the passive oxide layer. These changes accelerated corrosion: compared to the non-annealed alloy (0.0125 mm/year), the rate increased to 0.0356 mm/year at 500 °C and 0.313 mm/year at 700 °C. Concurrently, passive current density (I_pass) doubled from 20 to 40 <span>(mu )</span>A cm⁻², while the Pitting potential (E_pirs) shifted from +0.290 mV to –0.287 mV, indicating weaker passivation. EIS confirmed declining charge transfer resistance with temperature. Post-corrosion surface analysis confirmed these findings: SEM revealed increased roughness and defects, while EDX detected reduced oxygen content, consistent with thinning of the protective oxide film after annealing. Thus, high-temperature pre-annealing, therefore, markedly degrades corrosion resistance, underscoring the need for optimized heat treatment in dental applications.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144990557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation and modeling of the time-dependent double yielding process of polyamide","authors":"Makoto Uchida,&nbsp;Mei Toji,&nbsp;Keito Oya,&nbsp;Yoshihisa Kaneko,&nbsp;Mokarram Hossain","doi":"10.1007/s11043-025-09816-6","DOIUrl":"10.1007/s11043-025-09816-6","url":null,"abstract":"<div><p>Polyamide (PA) is a widely used semi-crystalline polymer that exhibits complex viscoelastic-viscoplastic behavior including the double-yielding (DY) phenomenon. Uniaxial tensile tests at different strain rates were performed using PA11 specimens obtained at different annealing temperatures to evaluate the effect of the strain rate on the DY phenomenon. The slope of the stress-strain curve after the first yield and the distance between the first and second yields increased with decreasing strain rate. In contrast, the maximum stress observed during the DY phenomenon was independent of the strain rate, and uniform deformation continued for a longer strain range at lower strain rates. The first yield stress was strain-rate dependent, whereas the second yielding stress was governed by the annealing temperature. These findings indicate that the first and second yielding events were characterized by the amorphous and crystalline phases, respectively. The viscoelastic-viscoplastic transient network model was generalized to reproduce the experimentally observed time-dependent DY phenomenon of PA11. Subsequently, a two-dimensional plane stress finite element model was established using the proposed method, and computational simulations of the uniaxial tensile tests were performed and compared with the experimental results. The simulation results reproduced the time-dependent characteristics of PA11, including changes in the first yielding stress, different degrees of hardening and softening during deformation between the first and second yields, and shifts in the strain at which the second yield occurred as a function of strain rate.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variable Poisson’s ratio and time-dependent failure of solid propellant: experiment and modeling","authors":"Kuangwei Deng,&nbsp;Haiyang Li,&nbsp;Zhibin Shen","doi":"10.1007/s11043-025-09814-8","DOIUrl":"10.1007/s11043-025-09814-8","url":null,"abstract":"<div><p>As a core component, the mechanical behavior and failure criterion of solid propellant grain are the key to environmental adaptability and safety of solid rocket motors. However, considering variable Poisson’s ratio with significant strain dependence as an elastic constant and failure behavior with loading time dependence as fixed limits are important factors in the current inaccuracy of motor structural integrity analyses. Here, a series of constant speed tensile and creep tests were carried out. The variable Poisson’s ratio phenomenon and time-dependent failure behavior of propellant were analyzed and discussed, and the microscopic mechanism was revealed. A model for predicting time-dependent failure behavior of composite materials is proposed, and each model parameter has a corresponding macroscopic and microscopic physical meaning. The validity of model prediction accuracy is verified in three working conditions, and the coefficient of determination R² is between 0.88 and 0.98. This work could provide theoretical and experimental guidance for long-term service life prediction and reliability evaluation of solid propellant, as well as other particle-reinforced materials.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal and flow analysis of chemically reactive Casson hybrid nanofluids with machine learning validation","authors":"P. Priyadharshini,&nbsp;M. Sowndharya,&nbsp;Ali J. Chamkha","doi":"10.1007/s11043-025-09812-w","DOIUrl":"10.1007/s11043-025-09812-w","url":null,"abstract":"<div><p><b>Background:</b> This research investigates the magnetohydrodynamic flow of a chemically reactive Casson hybrid nanofluid within a Sodium Alginate base, flowing over a curved stretching surface in a porous environment. The analysis accounts for internal heat sources, magnetic field influence, reactive diffusion, and thermophoretic effects to improve thermal performance. <b>Methodology:</b> The model considers transport effects, including Brownian motion, thermophoresis, internal heating, viscosity, and Arrhenius-type reactions. Similarity transformations reduce the governing PDEs to ODEs, which are solved using MATLAB’s BVP4c. The sensitivity of thermal and flow parameters is further evaluated using Multiple Linear Regression (MLR). <b>Core findings:</b> Results indicate that elevating the Biot number can boost the Nusselt number by approximately 42%, emphasizing improved heat transfer at the surface. The heat generation parameter exerts the strongest effect on thermal output, with a sensitivity index peaking at 2.8673. Furthermore, the curvature parameter plays a significant role in modulating surface shear. The sensitivity analysis pinpoints parameter combinations that yield optimal performance, reinforcing the utility of machine learning in fluid system optimization. <b>Validation:</b> Comparisons to previous studies demonstrate excellent agreement, as deviations remain under 1.6% for skin friction and 2.3% for the Nusselt number when the curvature parameter equals zero. These results affirm the robustness of the applied transformations and numerical approach. Furthermore, the MLR model perfectly matches numerical outputs, reaching an <span>(R^{2})</span> score of 1.0, confirming predictive accuracy. <b>Applications:</b> The findings reference engineering applications, specifically solar thermal systems, HVAC equipment, and miniaturized heat exchangers. By combining numerical modeling with machine learning, this study offers a reliable approach for designing and controlling energy-efficient thermal systems under varying physical conditions.</p></div>","PeriodicalId":698,"journal":{"name":"Mechanics of Time-Dependent Materials","volume":"29 3","pages":""},"PeriodicalIF":2.3,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144868934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}