International Journal of Non-Linear Mechanics最新文献

{"title":"Nonlinear free vibration analysis of imperfect cylindrical panels with discontinuous unilateral elastic base","authors":"Jordana L. Morais,&nbsp;Frederico M.A. Silva","doi":"10.1016/j.ijnonlinmec.2024.104884","DOIUrl":"10.1016/j.ijnonlinmec.2024.104884","url":null,"abstract":"<div><p>In this work, the nonlinear free vibration analysis of the imperfect cylindrical panels in contact with discontinuous unilateral elastic base are conducted, evaluating the influence of the type of contact, unilateral or bilateral, and the contact area of the elastic base on the natural frequencies and nonlinear frequency-amplitude relations. For that, the structural cylindrical panel model considers the Donnell's nonlinear shallow shell theory to obtain the partial differential equilibrium equation and the compatibility and continuity equation. To represent the unilateral capability of the elastic base, a signum function is inserted in the reaction force of the elastic base to describe its dependence of the transversal displacement field of the cylindrical panel. To apply the elastic base in certain subdomain of the cylindrical panel, a Heaviside-type function is also inserted into elastic base's reaction forces. The nonlinear equilibrium equation is discretized by the Galerkin method, using a consistent transversal displacement field that it was obtained from a perturbation technique. The discretized set of equilibrium equations is employed to obtain the natural frequencies and the nonlinear frequency-amplitude relations, evaluating the influence of the unilateral contact and the contact region of the elastic base on these results. Depending on the signal of the imperfection's magnitude and the type of contact of the elastic base, the imperfect cylindrical panel can display an initial gap between the cylindrical panel and the elastic base, and this possibility is also investigated in this work. From the numerical results, it is observed that the unilateral elastic base applies less structural stiffness than the bilateral elastic base, decreasing the natural frequencies for the same imperfect cylindrical panel. The localization of the elastic base in the cylindrical panel also affects the natural frequencies, increasing or decreasing them depending on the modifications on the structural stiffness. The frequency-amplitude relations are strongly influenced by both unilateral contact of elastic base and the type of the contact consideration between the cylindrical panel and elastic base, exhibiting an intricated nonlinear behavior.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104884"},"PeriodicalIF":2.8,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hysteresis and loss characteristics of metal rubber damper based on improved Preisach model","authors":"Zhijun Wang,&nbsp;Huirong Hao,&nbsp;Huijie Zhang,&nbsp;Jiawei Wang,&nbsp;Shijun Zou,&nbsp;Mianchen Liu,&nbsp;Zhanfeng Liu","doi":"10.1016/j.ijnonlinmec.2024.104877","DOIUrl":"10.1016/j.ijnonlinmec.2024.104877","url":null,"abstract":"<div><p>In this study, a new hysteresis mechanical model of metal rubber was developed based on the magnetic flux change of metal rubber damper after cyclic loading and the subsequent static stiffness degradation This new model aims to overcome the shortcomings of the traditional high-order friction theory hysteresis model in explaining the stiffness fluctuation and temperature magnetic flux change of the shock absorber. Through the large load cyclic loading experiment of the metal rubber damper, the hysteresis characteristics of the metal rubber damper without fatigue fracture were ana-lyzed in depth. Based on the electromagnetic theory and the force and displacement constitutive relationship of the metal rubber, the Preisach mechanical hysteresis model was established. The experimental test outcomes were substituted into the model for parameter identification and the model was modified as necessary. Compared to the traditional dynamic hysteresis model based on power series and elliptic equation, the Preisach model showed higher accuracy in simulating the energy dissipation and damping ratio of the experimental data of the shock absorber. The error was controlled within 2 %. Especially in the abrupt region of the unloading curve, the nonlinear stiffness error of the Preisach model was determined to be only half of that of the traditional model. The Preisach mechanical hysteresis model deeply explores the microscopic electromagnetic characteristics of the metal rubber damper, thus revealing the internal mechanism of its hysteresis change. This model can not only accurately simulate the sudden change of the curve of the shock absorber during the unloading process, but also make the model prediction closer to the actual application scenario through the highly simulated simulation results.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104877"},"PeriodicalIF":2.8,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142128788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crookedness detection of thrust ball bearing shaft washer based on nonlinear vibration responses","authors":"Hosein Razavian,&nbsp;Alireza Shooshtari","doi":"10.1016/j.ijnonlinmec.2024.104880","DOIUrl":"10.1016/j.ijnonlinmec.2024.104880","url":null,"abstract":"<div><p>Bearing misalignments are common defects in machinery. One of the most important types of that is the angular misalignment of the bearing rings. In this study, crookedness specific signature related to thrust ball bearing shaft washer is investigated. For this purpose, a vertical structural thrust ball bearing test rig was considered. In the following, effects of rotational shaft speed, crookedness value and axial external force on the shaft washer crookedness signature were studied at several relative positions of sensors. It is shown that crookedness of thrust ball bearing shaft washer has specific frequency and sensor phase difference pattern in the nonlinear vibration responses. Also, the experimental results are applied to validate results of a 4-dof nonlinear dynamical system related to the shaft washer crookedness of thrust ball bearing. In the next step, by comparing input and output amplitude and also existence of flip bifurcation, it is illustrated that this system is a nonlinear dynamical experimental system. It was shown that this nonlinearity makes crooked shaft washer pattern difficult to identify. Finally, by the phase portrait of the sensor response and the relative error value of crookedness signature frequencies, it is clear that the crookedness of shaft washer creates quasi-chaotic behavior supporting crookedness signature frequencies and phase pattern as a supplement property.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104880"},"PeriodicalIF":2.8,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142128789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Propagation of linear and weakly nonlinear waves in Hall-magnetohydrodynamic flows","authors":"Triveni P. Shukla ,&nbsp;V.D. Sharma","doi":"10.1016/j.ijnonlinmec.2024.104883","DOIUrl":"10.1016/j.ijnonlinmec.2024.104883","url":null,"abstract":"<div><p>We study in this paper linear and weakly nonlinear waves within the framework of a Hall-magnetohydrodynamic model. An optimal ordering, which allows the Hall effect to be seen in the leading order equations, is used to discuss the propagation of such waves; an evolution equation is obtained where the nonlinearity and Hall effect enter through the parameters that influence the wave propagation significantly. The interplay between nonlinearity and Hall effect leads to the emergence of a dispersive shock wave, which appears as the solution to the initial value problem associated with the evolution equation. The present study reveals a number of interesting flow characteristics which are not seen in the theory of ideal magnetohydrodynamics.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104883"},"PeriodicalIF":2.8,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142087117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 autocannon firing dispersion based on bond space method","authors":"Tian Tan ,&nbsp;Jinsong Dai ,&nbsp;Yongtao Zhang ,&nbsp;Qiang Huang ,&nbsp;Shengye Lin","doi":"10.1016/j.ijnonlinmec.2024.104876","DOIUrl":"10.1016/j.ijnonlinmec.2024.104876","url":null,"abstract":"<div><p>This paper is devoted to constructing a dynamic numerical model for the firing dispersion caused by the autocannon dynamic characteristics. The buffer dynamics and projectile-barrel coupling are considered. First, the simulation of autocannon firing dispersion using commercial software usually leads to expensive computational costs. Second, autocannon dynamic design includes multiple subsystem models with nonlinearities. The conventional design method makes it difficult to describe the dynamic response of such complex systems with a unified model. To end these, a dynamic junction bond space method is proposed for analyzing muzzle vibration and firing dispersion under continuous firing loads, where the gene expression programming (GEP) method is adopted to construct the surrogate model for the buffer flow field. For the coupling analysis of the projectile and barrel, the projectile load is applied at a moving junction, which coincides with the flexible node of the barrel. By this, the dynamic numerical model for autocannon firing dispersion is established, and then the system state equation is obtained for each time step. Moreover, an autocannon standing target shooting example is presented to demonstrate the validity of the proposed method; the results show that the firing dispersion from the bond space model is consistent with the test.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104876"},"PeriodicalIF":2.8,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142077241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extracting and analyzing the governing model for plastic deformation of metallic glasses","authors":"Liping Yu ,&nbsp;Xiaoxiang Guo ,&nbsp;Qigang Yuan ,&nbsp;Hongyi Zhu ,&nbsp;Jingli Ren","doi":"10.1016/j.ijnonlinmec.2024.104869","DOIUrl":"10.1016/j.ijnonlinmec.2024.104869","url":null,"abstract":"<div><p>This paper first detects hidden system from plastic deformation of metallic glasses by sparse identification. The extracted model simulates four types of stress-time curves and displays the prediction of serrated events. This interpretation effectively explains various experimental phenomena of repeated yielding. Further, in terms of parametric sensitivity analysis to the model, two parameters are taken as bifurcation parameter, and the analysis of codimension-one and codimension-two bifurcation are carried out to excavate the causes of dynamic transformation, including saddle–node bifurcation, Hopf bifurcation, Bogdanov–Takens bifurcation and cusp bifurcation. Different bifurcation points correspond different types of stress-time curves. The homologous phase diagrams including periodic orbit, unstable orbit and chaotic behavior are presented to show the dynamics diversity of the model. In addition to dynamic analysis, statistical analysis for plasticity values is also applied to excavate the crossover between periodic and chaotic plastic dynamic transitions. Our results provide a novel perspective on the deformation of metallic glasses from the viewpoint of dynamic model and are also important for evaluating the plastic deformation properties of metallic glasses in practical applications.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104869"},"PeriodicalIF":2.8,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142121950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vibration mitigation of a model aircraft with high-aspect-ratio wings using two-dimensional nonlinear vibration absorbers","authors":"Judith D. Brown ,&nbsp;Manal Mustafa ,&nbsp;Keegan J. Moore","doi":"10.1016/j.ijnonlinmec.2024.104878","DOIUrl":"10.1016/j.ijnonlinmec.2024.104878","url":null,"abstract":"<div><p>High-aspect-ratio (HAR) airplane wings have higher energy efficiency and present an economical alternative to standard airplane wings. HAR wings have a high span and a high lift-to-drag ratio, allowing the wing to require less thrust during flight. However, due to their length and construction, HAR wings exhibit low-frequency, high-amplitude vibrations in both vertical (yaw axis) and longitudinal (roll axis) directions. To combat these unwanted vibrations, a two-dimensional nonlinear vibration absorber (2D-NVA) is constructed and attached to a model HAR-wing airplane to verify its effectiveness at reducing vibrational motion. The 2D-NVA design, which was presented in a previous study, consists of two low-mass, rigid bodies namely the housing and the impactor. The housing consists of a ring-like rigid body in the shape of an ellipse, while the impactor is a solid cylindrical mass which resides inside the cavity of the housing. The 2D-NVA is designed such that the impactor can contact the inner surface of the housing under both impacts and constrained sliding motion. The present study focuses on the use of the 2D-NVA to mitigate multiple modes of vibration excited by impulsive loading of a model airplane with HAR wings in both vertical and longitudinal directions. The effectiveness of a single 2D-NVA is investigated computationally using a finite element model of the model airplane. These results are verified experimentally and the performance of two 2D-NVAs (one on each wing) is also investigated. The contributions of this work are that: 1) the 2D-NVA alters the global response of the model aircraft by mitigating all relevant modes in both directions simultaneously; 2) a single 2D-NVA is optimal for mitigating motion in the vertical direction, while two active 2D-NVAs are optimal for the longitudinal direction; and 3) the performance of the 2D-NVA is robust to changes in the frequency content of the parent structure.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104878"},"PeriodicalIF":2.8,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048923","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Instability, bifurcation and nonlinear dynamics of Poiseuille flow in fluid overlying an anisotropic and inhomogeneous porous domain","authors":"A. Aleria,&nbsp;P. Bera","doi":"10.1016/j.ijnonlinmec.2024.104873","DOIUrl":"10.1016/j.ijnonlinmec.2024.104873","url":null,"abstract":"<div><p>The present study focuses on the finite amplitude analysis of Poiseuille flow in an anisotropic and inhomogeneous porous domain that underlies a fluid domain. The nonlinear interactions are studied by imposing finite amplitude disturbances to the Poiseuille flow. The former interactions in terms of modal amplitudes dictate the fundamental mode, the distorted mean flow, the second harmonic and the distorted fundamental mode. The harmonics are solved progressively in increasing order of the least stable mode obtained from the linear theory to ascertain the cubic Landau equation, which in turn helps to determine the bifurcation phenomena. The presented weakly nonlinear theory predicts the existence of subcritical transition to turbulence of Poiseuille flow in such superposed systems. In general, on moving away from the bifurcation point, it is found that a decrease in the value of inhomogeneity (in terms of <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span>), Darcy number <span><math><mrow><mo>(</mo><mi>δ</mi><mo>)</mo></mrow></math></span> and an increase in the value of depth ratio (<span><math><mover><mrow><mi>d</mi></mrow><mrow><mo>ˆ</mo></mrow></mover></math></span>; the ratio of fluid domain thickness to that of porous domain) favours subcritical bifurcation. For the considered variation of parameters, the bifurcation, either subcritical or supercritical, remains the same irrespective of the value of media anisotropy (<span><math><mi>ξ</mi></math></span>) in the vicinity of the bifurcation point except for <span><math><mrow><mover><mrow><mi>d</mi></mrow><mrow><mo>ˆ</mo></mrow></mover><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn><mo>,</mo><msub><mrow><mi>A</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>=</mo><mn>1</mn></mrow></math></span>. In such a situation, subcritical (supercritical) bifurcation is witnessed for <span><math><mrow><mi>ξ</mi><mo>=</mo><mn>0</mn><mo>.</mo><mn>001</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>01</mn><mo>,</mo><mn>0</mn><mo>.</mo><mn>1</mn></mrow></math></span> (1,3). Furthermore, in contrast to isotropic and homogeneous porous media, both subcritical and supercritical bifurcations are observed when moving away from the bifurcation point. A correspondence between the type of mode via linear theory and the type of bifurcation via nonlinear theory is witnessed, which is further affirmed by the secondary flow patterns. Finally, the presented theoretical results reveal an early onset of subcritical transition to turbulence in comparison with isotropic and homogeneous porous media.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104873"},"PeriodicalIF":2.8,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics, stability and bifurcations of a planar three-link swimmer with passive visco-elastic joint using “ideal fluid” model","authors":"Elon Tovi,&nbsp;Anna Zigelman,&nbsp;Yizhar Or","doi":"10.1016/j.ijnonlinmec.2024.104859","DOIUrl":"10.1016/j.ijnonlinmec.2024.104859","url":null,"abstract":"<div><p>Articulated swimming robots have a promising potential for various marine applications. A common theoretical model assumes ideal fluid, where the viscosity is negligible and the swimmer–fluid interaction is induced by reactive forces originating from added mass effect. Some previous works used this model to study planar multi-link swimmers under kinematic input prescribing all joint angles. Inspired by biological swimmers in nature that utilize body flexibility, in this work we consider an underactuated three-link swimmer where one joint is periodically actuated while the other joint is passive and viscoelastic. Analysis of the swimmer’s nonlinear dynamics reveals that its motion depends significantly on the amplitude and frequency of the actuated joint angle. Optimal frequency is found where the swimmer’s net displacement per cycle is maximized, under symmetric periodic oscillations of the passive joint. In addition, upon crossing critical values of amplitude or frequency, the system undergoes a bifurcation where the symmetric periodic solution loses stability and asymmetric solutions evolve, for which the swimmer moves along an arc. We analyze these phenomena using numerical simulations and analytical methods of perturbation expansion, harmonic balance, Floquet theory, and Hill’s determinant. The results demonstrate the important role of parametric excitation in stability and bifurcations of motion for flexible underactuated locomotion.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104859"},"PeriodicalIF":2.8,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142012709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discrete mechanical model for nonlinear dynamical analysis of planar guyed towers considering the unilateral contact of cables","authors":"Fernanda N. Silva,&nbsp;Frederico M.A. Silva","doi":"10.1016/j.ijnonlinmec.2024.104875","DOIUrl":"10.1016/j.ijnonlinmec.2024.104875","url":null,"abstract":"<div><p>Towers are widely used for power line transmission, wind power plants, TV and radio broadcasting, and telecommunications. To enhance their stability, cables are often employed to anchor these towers to the ground. In this study, we investigate the nonlinear static and dynamic responses of a planar guyed tower in which the unilateral constraints on the cables are considered. A representative discrete mechanical model with two degrees of freedom is developed to simulate the central mast of the tower, and the cables are modeled as unilateral springs with linear stiffness. The nonlinear equilibrium equations are derived using an energy approach that incorporates the dissipative forces, total potential, and kinetic energies into the Euler-Lagrange equations. Unilateral cable contact is directly included in the nonlinear equilibrium equation for the guyed tower, allowing for numerical analysis without the need to evaluate the contact point at each time or load step. Several numerical strategies are employed to obtain nonlinear static equilibrium paths, bifurcation diagrams, phase portraits, and Poincaré sections. Our analyses provide novel results for the influence of unilateral cable contact in nonlinear static and dynamic analysis, evaluating the effects of unilateral contact and prestressing on the results. A parametric analysis reveals that cable contact affects nonlinear oscillations, bifurcation, and stability. Our numerical results indicate that unilateral cable contact introduces less structural stiffness compared to bilateral contact, thereby significantly affecting the static and dynamic stability of a planar guyed tower. This is evidenced by a decrease in the static limit load and alterations in the bifurcation diagrams, where unilateral contact destroys the trivial solutions, leading to periodic and quasi-periodic solutions at low levels of vertical load.</p></div>","PeriodicalId":50303,"journal":{"name":"International Journal of Non-Linear Mechanics","volume":"167 ","pages":"Article 104875"},"PeriodicalIF":2.8,"publicationDate":"2024-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}