Computer Methods in Applied Mechanics and Engineering最新文献

{"title":"DHRDE: Dual-population hybrid update and RPR mechanism based differential evolutionary algorithm for engineering applications","authors":"","doi":"10.1016/j.cma.2024.117251","DOIUrl":"10.1016/j.cma.2024.117251","url":null,"abstract":"<div><p>In this paper, an enhanced differential evolution algorithm based on dual population hybrid update and random population replacement strategy (namely RPR mechanism) is proposed, which is called DHRDE. DHRDE algorithm involves three key improvements, first, the elite reverse population is constructed according to the original population before the update phase to uncover more potential areas to be searched. Second, a perturbation mechanism is integrated into the DE/rand/2 approach of the differential evolution algorithm to bolster its search efficiency, two updating models are established using co-leadership of random and locally optimal individuals, and then dual-population hybrid update strategy is adopted to achieve all-round and multi-angle search. Thirdly, using RPR mechanism to operate multiple types of mutations on some populations further improves the convergence accuracy. In order to verify the effectiveness of the proposed algorithm, DHRDE is compared with a variety of different types of algorithms in multi-dimension of the CEC2017, CEC2020 and CEC2022 test set, and statistical analysis is performed by Wilcoxon rank sum test and Friedman test. The results show that DHRDE algorithm has better performance. DHRDE algorithm is also used to solve seven engineering design problems and three PV model parameter estimation problems, the optimization results show that DHRDE algorithm is suitable for different complex problems and has effectiveness. In addition, this paper establishes a smooth path planning model for multi-size robots, and uses DHRDE to solve the model, the results of five groups of simulation experiments show that DHRDE algorithm can provide robot moving trajectories with higher smoothness and shorter paths. Analyzing and comparing the fitness metrics through heat maps, the comparative study demonstrates that the DHRDE algorithm is more advantageous and stronger than other algorithms in solving the smooth path planning model for multi-size robots. The above results show that DHRDE algorithm has better performance and has great advantages and competitiveness in solving engineering application optimization problems.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141993893","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discontinuous Galerkin approximations of the heterodimer model for protein–protein interaction","authors":"","doi":"10.1016/j.cma.2024.117282","DOIUrl":"10.1016/j.cma.2024.117282","url":null,"abstract":"<div><p>Mathematical models of protein–protein dynamics, such as the heterodimer model, play a crucial role in understanding many physical phenomena, e.g., the progression of some neurodegenerative diseases. This model is a system of two semilinear parabolic partial differential equations describing the evolution and mutual interaction of biological species. This article presents and analyzes a high-order discretization method for the numerical approximation of the heterodimer model capable of handling complex geometries. In particular, the proposed numerical scheme couples a Discontinuous Galerkin method on polygonal/polyhedral grids for space discretization, with a <span><math><mi>θ</mi></math></span>-method for time integration. This work presents novelties and progress with respect to the mathematical literature, as stability and a-priori error analysis for the heterodimer model are carried out for the first time. Several numerical tests are performed, which demonstrate the theoretical convergence rates, and show good performances of the method in approximating traveling wave solutions as well as its flexibility in handling complex geometries. Finally, the proposed scheme is tested in a practical test case stemming from neuroscience applications, namely the simulation of the spread of <span><math><mi>α</mi></math></span>-synuclein in a realistic test case of Parkinson’s disease in a two-dimensional sagittal brain section geometry reconstructed from medical images.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0045782524005383/pdfft?md5=71b8f7ba57ab2cf5729c1770cb3bf0d2&pid=1-s2.0-S0045782524005383-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141984694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A transfer learning physics-informed deep learning framework for modeling multiple solute dynamics in unsaturated soils","authors":"","doi":"10.1016/j.cma.2024.117276","DOIUrl":"10.1016/j.cma.2024.117276","url":null,"abstract":"<div><p>Modeling subsurface flow and transport phenomena is essential for addressing a wide range of challenges in engineering, hydrology, and ecology. The Richards equation is a cornerstone for simulating infiltration, and when coupled with advection–dispersion equations, it provides insights into solute transport. However, the complexity of this coupled model increases significantly when dealing with multiple solute transport. Physics-informed neural networks (PINNs) offer a flexible technique that merges data-driven approaches with the underlying physics principles, enabling the direct incorporation of physical laws or constraints into the neural network training process. Nevertheless, employing PINNs for solving multi-physics problems can present challenges during training, particularly in achieving convergence to realistic concentration profiles. Our study introduces a transfer learning technique to tackle the challenge of modeling multiple species transport in unsaturated soils. This approach aims to improve the accuracy of the PINN framework by decoupling the training process and solving the governing partial differential equations (PDEs) sequentially. We incorporate various strategies to optimize and accelerate the training process. Specifically, we begin by solving the Richards equation and then transfer the acquired knowledge to subsequent solute PINN solvers. This strategy leverages the fact that these PDEs have some similarities in their structure as advection–diffusion equations. To rigorously validate our approach, we conduct 1D numerical experiments and extend our analysis to encompass 2D problems, and inverse problems for homogeneous soils, as well as numerical tests using layered soils. Our findings indicate that transferring learned features is more advantageous than utilizing random features, highlighting the effectiveness of the proposed strategy.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computationally-efficient locking-free isogeometric discretizations of geometrically nonlinear Kirchhoff–Love shells","authors":"","doi":"10.1016/j.cma.2024.117280","DOIUrl":"10.1016/j.cma.2024.117280","url":null,"abstract":"<div><p>Discretizations based on the Bubnov-Galerkin method and the isoparametric concept suffer from membrane locking when applied to Kirchhoff–Love shell formulations. Membrane locking causes not only smaller displacements than expected, but also large-amplitude spurious oscillations of the membrane forces. Continuous-assumed-strain (CAS) elements were originally introduced to remove membrane locking in quadratic NURBS-based discretizations of linear plane curved Kirchhoff rods (Casquero et al., CMAME, 2022). In this work, we propose <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>s</mtext></mrow></msup></math></span> and <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>ns</mtext></mrow></msup></math></span> elements to overcome membrane locking in quadratic NURBS-based discretizations of geometrically nonlinear Kirchhoff–Love shells. <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>s</mtext></mrow></msup></math></span> and <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>ns</mtext></mrow></msup></math></span> elements are interpolation-based assumed-strain locking treatments. The assumed strains have <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>0</mn></mrow></msup></math></span> continuity across element boundaries and different components of the membrane strains are interpolated at different interpolation points. <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>s</mtext></mrow></msup></math></span> elements use the assumed strains to obtain both the physical strains and the virtual strains, which results in a global tangent matrix which is a symmetric matrix. <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>ns</mtext></mrow></msup></math></span> elements use the assumed strains to obtain only the physical strains, which results in a global tangent matrix which is a non-symmetric matrix. To the best of the authors’ knowledge, <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>s</mtext></mrow></msup></math></span> and <span><math><msup><mrow><mtext>CAS</mtext></mrow><mrow><mtext>ns</mtext></mrow></msup></math></span> elements are the first assumed-strain treatments to effectively overcome membrane locking in quadratic NURBS-based discretizations of geometrically nonlinear Kirchhoff–Love shells while satisfying the following important characteristics for computational efficiency: (1) No additional unknowns are added, (2) No additional systems of algebraic equations need to be solved, (3) The same elements are used to approximate the displacements and the assumed strains, (4) No additional matrix operations such as matrix inversions or matrix multiplications are needed to obtain the stiffness matrix, and (5) The nonzero pattern of the stiffness matrix is preserved. Analogously to the interpolation-based assumed-strain locking treatments for Lagrange polynomials that are widely used in commercial FEA software, the implementation of <span><math><msup><mr","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep material network for thermal conductivity problems: Application to woven composites","authors":"","doi":"10.1016/j.cma.2024.117279","DOIUrl":"10.1016/j.cma.2024.117279","url":null,"abstract":"<div><p>The thermal conductivity of materials dictates their functionality and reliability, especially for materials with complex microstructural topologies, such as woven composites. In this paper, we develop a physics-informed machine-learning architecture built specifically for solving thermal conductivity problems. Originally developed for mechanical problems, we extend and develop a deep material network (DMN) that incorporates (i) principles from thermal homogenization directly into the network architecture in which nodes propagate heat flux and temperature gradient (as opposed to stress and strain in the original ‘mechanical’ DMN) and (ii) nodal rotations to capture the topological complexity of the materials’ microstructure. The result is a ‘thermal’ DMN better suited for thermal conductivity problems than the ‘mechanical’ deep material network. We demonstrate the ability of this ‘thermal’ DMN to act as an accurate reduced order model with a significantly smaller number of degrees of freedom on two different woven microstructures examples. Our results show that the ‘thermal’ DMN can not only accurately predict the averaged effective thermal conductivity of these complex weaved composite structures but also the distribution of local heat flux and temperature gradients. Based on these performances, we show how this ‘thermal’ DMN can be exercised for rapid uncertainty and sensitivity analyses to assess microstructure effects and variability of the properties of the composite’s constituents, a task that would be otherwise computationally prohibitive with direct numerical simulations. Based on its architecture, the ‘thermal’ DMN opens possibilities for multiscale, multiphysics simulations for a heterogeneous structure, especially when coupled with its mechanical counterpart.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0045782524005358/pdfft?md5=3786150c8d37e39cf2ec3f69877b1b82&pid=1-s2.0-S0045782524005358-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141964595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Maximum energy dissipation-based incremental approach for structural analyses involving discrete fracture propagation in quasi-brittle materials","authors":"","doi":"10.1016/j.cma.2024.117263","DOIUrl":"10.1016/j.cma.2024.117263","url":null,"abstract":"<div><p>A maximum energy dissipation-based incremental approach (MEDIA) is proposed to overcome limit points, e.g. strong snap-backs, in the fracture analysis of quasi-brittle materials. An optimisation step is applied using an expression proposed to compute the change of dissipated energy within the discretised body when moving from one state of equilibrium to another. This expression is developed at the integration point level and uses a binary pathway vector to define all the possible solutions within that step. Due to the unique way the problem is cast, a genetic algorithm is deployed to identify the solution leading to the highest energy dissipation while following applicable thermodynamic constraints. The resulting analysis is non-iterative and purely incremental. MEDIA is particularly applicable in combination with discrete crack models. In this case, meshes are relatively coarse and each crack can be individually handled to maintain the computational cost independent of the discretisation. The equations are also cast in a direct inverse method that avoids explicitly solving the inversion of the stiffness matrices for each chromosome in the genetic optimisation. Problems having multiple snap-back effects and non-proportional loading, as well as lightly and highly reinforced concrete beams, are used to assess the suitability and efficiency of the proposed method. In contrast with other available techniques, MEDIA is shown to follow the adopted constitutive models without any energy loss due to the solution-finding process while providing adequate structural responses.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 stabilization-free hybrid virtual element formulation for the accurate analysis of 2D elasto-plastic problems","authors":"","doi":"10.1016/j.cma.2024.117281","DOIUrl":"10.1016/j.cma.2024.117281","url":null,"abstract":"<div><p>A plasticity formulation for the Hybrid Virtual Element Method (HVEM) is presented. The main features include the use of an energy norm for the VE projection, a high-order divergence-free interpolation for stresses and a piecewise constant interpolation for plastic multipliers within element subdomains. The HVEM does not require any stabilization term, unlike classical VEM formulations which are affected by the choice of stabilization parameters. The algorithmic tangent matrix is derived consistently and analytically. A standard strain-driven formulation and a Backward-Euler time integration scheme are adopted. The return mapping process for the stress evaluation is formulated at the element level to preserve the stress interpolation as plasticity evolves. Even though general constitutive laws can be readily considered, to test the robustness of HVEM, an elastic-perfectly plastic behavior is adopted. In such a case, the return mapping process is efficiently solved using a Sequential Quadratic Programming Algorithm. The solution is free from volumetric locking and from spurious hardening effects that are observed in stabilized VEM. The numerical results confirm the accuracy of HVEM for rough meshes and high rate of convergence in recovering the collapse load.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0045782524005371/pdfft?md5=201a2647e300c21d486b557478b8aa16&pid=1-s2.0-S0045782524005371-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141964594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A fully explicit isogeometric collocation formulation for the dynamics of geometrically exact beams","authors":"","doi":"10.1016/j.cma.2024.117283","DOIUrl":"10.1016/j.cma.2024.117283","url":null,"abstract":"<div><p>We present a fully explicit dynamic formulation for geometrically exact shear-deformable beams. The starting point of this work is an existing isogeometric collocation (IGA-C) formulation which is explicit in the strict sense of the time integration algorithm, but still requires a system matrix inversion due to the use of a consistent mass matrix. Moreover, in that work, the efficiency was also limited by an iterative solution scheme needed due to the presence of a nonlinear term in the time-discretized rotational balance equation. In the present paper, we address these limitations and propose a novel <em>fully explicit</em> formulation able to preserve high-order accuracy in space. This is done by extending a predictor–multicorrector approach, originally proposed for standard elastodynamics, to the case of the rotational dynamics of geometrically exact beams. The procedure relies on decoupling the Neumann boundary conditions and on a rearrangement and rescaling of the mass matrix. We demonstrate that an additional gain in terms of computational cost is obtained by properly removing the angular velocity-dependent nonlinear term in the rotational balance equation without any significant loss in terms of accuracy. The high-order spatial accuracy and the improved efficiency of the proposed formulation compared to the existing one are demonstrated through some numerical experiments covering different combinations of boundary conditions.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0045782524005395/pdfft?md5=590597dc706f34bd29b4b7f05951b708&pid=1-s2.0-S0045782524005395-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A critical review/look at “Optimal implicit single-step time integration methods with equivalence to the second-order-type linear multistep methods for structural dynamics: Accuracy analysis based on an analytical framework”","authors":"","doi":"10.1016/j.cma.2024.117272","DOIUrl":"10.1016/j.cma.2024.117272","url":null,"abstract":"<div><p>A critical look and review of the so-called generalized single-step time integration method by Zhang (<em>CMAME</em>, 418(2024), 116503) is proved and demonstrated to be not new, but identical to and within the existing GS4-II computational framework. The following are addressed: (1) Firstly, it is claimed that 16 parameters were introduced (somewhat misleading as evident in what follows) to obtain a more generalized single-step mathematical formulation. We show that 4 conditions are made redundant with minimum consistency requirements, and thus, the framework is not new and is identical to the original version of the GS4-II computational framework with 12 parameters. (2) Then, the overshooting behavior is revisited, and the analysis, missteps, and information are clarified and corrected in this paper, which is significant. (3) Next, the time shift phenomenon is also revisited to show the recovery of the order of time accuracy in the acceleration, which is misunderstood in much of the existing literature. (4) Lastly, each design in the so-called newly proposed schemes already exists and is found in the GS4-II computational framework. In particular, via GS4-II we additionally prove and demonstrate that the so-called “Optimal Equivalent Single-step with Single parameter (OESS)” scheme by Zhang (<em>CMAME</em>, 418(2024), 116503) is nothing but identical to the existing Three-Parameters Optimal/Generalized-<span><math><mi>α</mi></math></span> method within the GS4-II framework for physically undamped problems. Furthermore, it is noteworthy to point out that also within the GS4-II framework, for physically damped problems, U0/U0<span><math><msup><mrow></mrow><mrow><mo>∗</mo></mrow></msup></math></span>, TPO/G-<span><math><mi>α</mi></math></span>, and OESS all share the same undesired overshooting deficiency in comparison to V0/V0<span><math><msup><mrow></mrow><mrow><mo>∗</mo></mrow></msup></math></span>. Numerical examples validate the issues identified about the accuracy and overshooting analysis.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141910778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two and three dimensional H2-conforming finite element approximations without C1-elements","authors":"","doi":"10.1016/j.cma.2024.117267","DOIUrl":"10.1016/j.cma.2024.117267","url":null,"abstract":"<div><p>We develop a method to compute <span><math><msup><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>-conforming finite element approximations in both two and three space dimensions using readily available finite element spaces. This is accomplished by deriving a novel, equivalent mixed variational formulation involving spaces with at most <span><math><msup><mrow><mi>H</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span>-smoothness, so that conforming discretizations require at most <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>0</mn></mrow></msup></math></span>-continuity. The method is demonstrated on arbitrary order <span><math><msup><mrow><mi>C</mi></mrow><mrow><mn>1</mn></mrow></msup></math></span>-splines.</p></div>","PeriodicalId":55222,"journal":{"name":"Computer Methods in Applied Mechanics and Engineering","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141910771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}