Mechanics of Materials最新文献

{"title":"CRSS evolution with changing grain size for a dual-phase Ti-6Al-2Sn-4Zr-2Mo-Si alloy having a martensite structure","authors":"Irvin Séchepée ,&nbsp;Hiroaki Matsumoto ,&nbsp;Hugo Rousseaux ,&nbsp;Vincent Velay ,&nbsp;Vanessa Vidal","doi":"10.1016/j.mechmat.2025.105407","DOIUrl":"10.1016/j.mechmat.2025.105407","url":null,"abstract":"<div><div>Duplex martensitic microstructures have recently attracted significant attention due to their unique ability to combine high strength, excellent ductility, and superior work-hardening properties, making them ideal for structural applications. This study explores the micromechanisms underlying the tensile properties of a Ti-6Al-2Sn-4Zr-2Mo-Si alloy with hot-rolled T-split textures and various microstructures, tested along two tensile directions: TensileD//RD (referred to as 0°) and TensileD⊥RD (referred to as 90°). A comparative analysis highlights the superior work-hardening capacity and isotropic behavior of duplex (α+α′) and (α+α\") microstructures containing martensite, compared to equiaxed (α+β) microstructures. The enhanced work-hardening observed in the duplex microstructures is attributed to mechanisms such as variant reorientation in the martensitic phases, the pronounced mechanical contrast between the harder α phase and the softer α'/α\" phases, and the interactions between α slipping and α'/α\" twinning. Macroscopic Hall-Petch relations further clarify how microstructures influence strength and ductility. Specifically, duplex (α+α′) microstructures exhibit improved ductility due to lower Hall-Petch constants and diminished grain boundary effects. Interestingly, reverse Hall-Petch behavior is observed in the duplex (α+α\") microstructure at 90°, which is associated with the presence of α\" martensite. Slip trace analysis is conducted to determine the experimental Critical Resolved Shear Stress (CRSS) ratios and qualitatively assess the impact of grain size and tensile direction on the activation of slip systems. Multiscale simulations are then utilized to calculate CRSS values and investigate the roles of deformation modes and crystallographic texture in shaping the macroscopic behavior of duplex (α+α\") microstructures. At 0°, the T-split texture and the facilitation of prismatic&lt;a&gt; slip between adjacent prismatic grains result in a low Hall-Petch constant and minimal grain boundary effects, acting as soft grains. In contrast, basal&lt;a&gt; and pyramidal&lt;c+a&gt; systems exhibit much higher Hall-Petch constants, behaving as hard grains and significantly contributing to work hardening. At 90°, basal&lt;a&gt; slips uniquely display reverse Hall-Petch behavior, which is linked to the macroscopic reverse Hall-Petch phenomenon. This behavior is thought to stem from the presence of α\" martensite and the hot-rolled texture, combined with the tensile direction of 90°, which triggers a shift in the dominant mechanism around basal grains from intragrain dislocation movement to grain boundary sliding.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"208 ","pages":"Article 105407"},"PeriodicalIF":3.4,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inverse design of interpenetrating phase composites with targeted stiffness through deep learning","authors":"Kaiyu Wang,&nbsp;Xin-Lin Gao","doi":"10.1016/j.mechmat.2025.105399","DOIUrl":"10.1016/j.mechmat.2025.105399","url":null,"abstract":"<div><div>Interpenetrating phase composites (IPCs) contain at least two interconnected phases. It is still challenging to establish the topology-property mapping and inversely design IPCs with targeted properties. A deep learning model is proposed to design new IPCs with various material symmetries. Hybrid triply periodic minimal surface (TPMS) scaffolds are mathematically designed as the reinforcement phase to construct the IPCs. The IPCs display orthotropic, tetragonal and cubic material symmetries, whose stiffness tensors are determined using a numerical homogenization method. A robust dataset is generated to establish the topology-property mapping. Then, a tandem dual-network model, including a forward sub-model and an inverse sub-model, is developed to predict the stiffness tensor and design the topologies. In addition, the hyperparameters are optimized to improve the accuracy of the model. The dual-network model provides excellent prediction and design capabilities. Moreover, the inversely designed IPCs can fulfill the requirements of the targeted stiffness both in and beyond the original dataset, which include orthotropic, tetragonal and cubic material properties. The current study provides a feasible approach to the forward prediction of elastic properties and inverse design of topologies through deep learning.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"208 ","pages":"Article 105399"},"PeriodicalIF":3.4,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144489525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Full-field elastic strain tensor evolution of 3D polycrystals with recurrent neural networks and transfer learning","authors":"Ashley Lenau ,&nbsp;Reeju Pokharel ,&nbsp;Alexander Scheinker ,&nbsp;Stephen Niezgoda","doi":"10.1016/j.mechmat.2025.105389","DOIUrl":"10.1016/j.mechmat.2025.105389","url":null,"abstract":"<div><div>High energy X-ray diffraction microscopy (HEDM) is a non-destructive characterization technique that enables the study of material evolution under in situ thermo-mechanical conditions. While HEDM provides valuable insights, successful experiments require extensive planning, data collection, and data reduction, making them time-intensive and expensive. Crystal plasticity simulations could improve experimental planning and reduce the time required for experimental data reconstruction, but they are too computationally intensive for real-time experimental feedback. Deep learning models offer the speed needed for real-time feedback that could optimize data collection and data reconstruction while expanding the experimental design space. However, these models are currently limited by the small size of available training datasets. This work develops a surrogate crystal plasticity model using a U-Net architecture with recurrent and recursive connections to predict the evolution of full-field elastic strain tensors in 3D polycrystalline materials—properties directly measured during HEDM experiments. Using a Cu polycrystal as the baseline material, the trained network can make predictions instantaneously, representing a significant step towards real-time crystal plasticity predictions for HEDM experiments and potentially enabling more efficient and adaptive experimental designs. However, training such a 3D network for different materials system is computationally expensive due to its numerous trainable parameters and the cost of generating training data. To address this challenge, we investigate transfer learning techniques that enable the network to predict the evolution of different materials without training from scratch, while using the Cu-trained network as a foundation for expanding the model’s capabilities. The transfer learning approach successfully reduced training time and data requirements while maintaining prediction accuracy for materials with similar microstructures, demonstrating the potential for rapid adaptation to new material systems.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"208 ","pages":"Article 105389"},"PeriodicalIF":3.4,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive study on the effectiveness of the stress and damage model parameters in predicting the compression fracture behavior of selective laser melted AlSi10Mg BCC lattices","authors":"Mustafa Güden ,&nbsp;Hacer İrem Erten ,&nbsp;Recep M. Gorguluarslan ,&nbsp;Umut Can Gülletutan ,&nbsp;Akın Dağkolu ,&nbsp;İstemihan Gökdağ ,&nbsp;Ahmet Can Günaydın ,&nbsp;Sertaç Altınok ,&nbsp;Halil İbrahim Erol ,&nbsp;Subhan Namazov","doi":"10.1016/j.mechmat.2025.105395","DOIUrl":"10.1016/j.mechmat.2025.105395","url":null,"abstract":"<div><div>The Johnson and Cook (JC) stress and damage model parameters determined from the machined bulk cylindrical specimens and as-built struts through tension and compression tests were used to model quasi-static compression behavior of selective laser melt-fabricated AlSi10Mg alloy lattices. The lattices had the same cell size (10 mm) and strut diameter (1 mm), but different number of cells (2 × 2 × 2, 10 × 10 × 2 and 5 × 5 × 5) and geometries (sandwich and cubic). Four different sets of JC damage model parameters (brittle and ductile notch-insensitive and compression and tension notch-sensitive) were further implemented in the lattice compression numerical models. The brittle damage model parameters and smaller mesh sizes resulted in cracking the face-sheet corner strut nodes before the occurrence of a bending-dominated initial peak stress. The notch-sensitive damage model parameters exhibited no bent-strut fracture in the middle layers of the lattices and increased the crack initiation strains as compared with the notch-insensitive damage model parameters. Despite significant variations in the initial peak stresses of the tested 2 × 2 × 2 and 10 × 10 × 2 lattices, the implication of the strut micro-tension stress model together with the compression notch-sensitive damage model parameters using 0.25 mm mesh size conservatively approximated the experimental deformation stresses while the machined bulk specimen tension-stress model over predicted the experimental stresses. On the other side, the strut stress model with 0.15 mm mesh size accurately predicted the experimental diagonal shear/fracture mode of struts with a slightly higher numerical initial peak stress. The compression tests on the strut specimens extracted from the as-built lattices yielded similar stress model parameters with the micro-tension tests. The differences between the initial peak stresses of the investigated sandwich and cubic lattices were further explained by the differences in the lattice boundary conditions.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"208 ","pages":"Article 105395"},"PeriodicalIF":3.4,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144632455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Model of enhanced flexural strength of ceramics at elevated temperatures","authors":"A.G. Sheinerman","doi":"10.1016/j.mechmat.2025.105398","DOIUrl":"10.1016/j.mechmat.2025.105398","url":null,"abstract":"<div><div>We suggest a model that describes the observed non-monotonous temperature dependences of the flexural strength of ceramics. Within the model, the flexural strength is affected by the sliding of the intergranular boundaries, which can blunt the crack tip and increase the flexural strength at certain temperatures. At the same time, at high enough temperatures, enhanced boundary sliding results in the transition from the brittle to ductile failure, which reduces the flexural strength. It is demonstrated that the fracture strength of ceramics at elevated temperatures can be strongly affected by the sliding properties of the intergranular boundaries and the loading time. The ceramics with the highest fracture strength should have low sliding resistance at short-term loading and high sliding resistance in the case of long-term loading. The results of the model quantitatively agree with experimental data.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"208 ","pages":"Article 105398"},"PeriodicalIF":3.4,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ab initio calculation of surface elasticity parameters in cubic crystalline films with surface point defects: Effects on SH wave propagation","authors":"P. Behnoud ,&nbsp;H.M. Shodja","doi":"10.1016/j.mechmat.2025.105366","DOIUrl":"10.1016/j.mechmat.2025.105366","url":null,"abstract":"<div><div>Elastic material surface and interface properties have non-negligible influences on the behavior of nano-sized elastic objects. Even though the concern and the need for the evaluation of surface properties were raised in 1876 by Gibbs, due to serious experimental and theoretical difficulties their measurements have remained idle till only recently. This paper offers a theoretical approach for an accurate evaluation of free surface energy density, surface layer relaxation, surface elastic constants, surface residual stresses, and surface mass density for the (100) and (111) planes of several non-magnetic cubic metals. Moreover, the analysis is extended to the surfaces where point defects, such as vacancies and substitutional impurity atoms, are present. The interaction of these point defects with surface is in particular important for irradiation and fracture phenomena. The present results are compared with the recent available experimental and theoretical data. For the sake of illustration of the importance of surface effects, the propagation of horizontally polarized shear waves (SH waves) in ultra-thin layers of only a few lattice parameters height will be studied. Utilizing the theoretically calculated surface parameters herein, the surface effects with and without the above-mentioned surface point defects will be examined in some details. Thus, the negative dispersion of SH waves within surface elasticity theory will be showcased quantitatively for various cubic crystals of interest. Moreover, the effects of the crystallographic orientations will also be examined in the presence and absence of surface point defects.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105366"},"PeriodicalIF":3.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental verification of dynamic fracture performance of concrete via rate-dependent cohesive interface approach and mesoscale model","authors":"Li Sun ,&nbsp;Xingye Wang ,&nbsp;Chunwei Zhang","doi":"10.1016/j.mechmat.2025.105397","DOIUrl":"10.1016/j.mechmat.2025.105397","url":null,"abstract":"<div><div>This study investigates the dynamic fracture behavior of concrete under higher loading rate using a combination of notch semi-circular bending (NSCB) experiments and rate-dependent cohesive zone modelling (CZM). The experimental setup employed a split Hopkinson pressure bar (SHPB) system coupled with high-speed digital image correlation (DIC) to capture real-time crack propagation and deformation. A 2D mesoscale finite element model was developed using digital image processing (DIP) and random aggregate generation techniques to replicate the heterogeneous microstructure of concrete. Cohesive elements with velocity-dependent traction-separation laws were integrated at interfacial transition zones (ITZ) and aggregate-matrix interfaces to simulate crack initiation and growth. Results revealed that dynamic fracture toughness increased linearly with loading rates, with peak values up to 144 % higher than quasi-static counterparts at 120 MPa. Notch angle significantly influenced mixed-mode fracture toughness, with a maximum <em>K</em>_<em>IIC</em> of 5.165 observed at a 30° notch angle. The study demonstrated that incorporating rate effects and microstructural heterogeneity into cohesive models improves predictive accuracy, offering critical insights for designing concrete structures subjected to dynamic loading.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"208 ","pages":"Article 105397"},"PeriodicalIF":3.4,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of crystal orientations and loading conditions on the microstructure evolution and void evolution dynamics in single crystal iron: An atomistic investigation","authors":"Sunil Rawat ,&nbsp;Vinay Rastogi","doi":"10.1016/j.mechmat.2025.105387","DOIUrl":"10.1016/j.mechmat.2025.105387","url":null,"abstract":"<div><div>An understanding of void evolution dynamics is required to develop/improve fracture models at a high strain rate to predict spall fracture at the macroscale. We perform molecular dynamics simulations to explore the role of crystal orientations and loading conditions on the microstructure evolution and void evolution dynamics in single-crystal iron. We find that all the cases of crystal orientations show structural transformations consistent with experiments. The dominance of the nucleation and growth of voids is sensitive to the applied loading conditions and crystal orientations. Void growth dominates under uniaxial deformation, and void nucleation dominates under triaxial deformation. Peak tensile pressure, the amount of structural transformation, and overall void volume fraction are insensitive to the crystal orientations under triaxial deformation, while they are susceptible under uniaxial and biaxial deformations. The dislocation evolution, number of voids, and size distributions of voids are all very sensitive to the applied loading conditions and crystal orientations. A small percentage of voids accounts for the majority of the total volume of the voids.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105387"},"PeriodicalIF":3.4,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-the-fly adaptive sampling strategy for data-driven computational mechanics: Applications to computational homogenisation","authors":"Felipe Rocha ,&nbsp;Auriane Platzer ,&nbsp;Adrien Leygue ,&nbsp;Laurent Stainier","doi":"10.1016/j.mechmat.2025.105382","DOIUrl":"10.1016/j.mechmat.2025.105382","url":null,"abstract":"<div><div>To overcome well-known drawbacks of classical phenomenological constitutive modelling of non-linear heterogeneous materials, a popular approach is the so-called computational homogenisation (CH), which relies on a combined description of constitutive behaviours and spatial morphology of smaller scales constituents. Their computational implementation usually encompasses two-level finite element numerical models (FE<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>), which quickly leads to prohibitive computational costs, even for problems with a modest number of degrees of freedom. A popular strategy in the literature to alleviate such computational burden is to use machine learning-based surrogate constitutive models, although fundamental drawbacks such as the absence of interpretability, limited extrapolation capability, and limited mathematical analysis, are still present. On the other hand, the so-called (model-free) data-driven computational mechanics (DDCM) paradigm Kirchdoerfer and Ortiz (2016) proposes the direct integration of “experimental data”, completely bypassing the need for explicit constitutive laws. The main goal of this work is to show how the DDCM approach can be used in synergy with CH to bypass fully-coupled multiscale computations. A naive approach to using multiscale constitutive behaviour along with DDCM is the offline construction of a database via CH by assuming some sampling of the strain-space. This approach has little interest since the region of the strain-space covered during a simulation is problem-dependent. During the iterations of the DDCM solver, a finite set of strain–stress pairs is used as input, while another set, comprising mechanically admissible states, is dynamically generated. Such a scenario naturally unveils the most relevant goal-oriented phase-space instances to guide a material dataset enrichment iterative procedure, bridging DDCM and CH towards computationally effective two-scale simulations. On the other hand, the performance is limited if the quality of the mechanically admissible states is low, particularly when the material dataset is not insufficiently dense. To address these challenges, we propose meaningful ranking scores alongside numerical techniques to enhance the DDCM solver in sparse data scenarios. As result, we show through meaningful numerical examples that the proposed framework results in significant computational savings if compared to standard FE<span><math><msup><mrow></mrow><mrow><mn>2</mn></mrow></msup></math></span>.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105382"},"PeriodicalIF":3.4,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144169465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration of digital volume correlation in nominally homogeneous metals","authors":"K. Jose,&nbsp;Z. Meng,&nbsp;A.R. Dennis,&nbsp;I. Grega,&nbsp;A.J.D. Shaikeea,&nbsp;V.S. Deshpande","doi":"10.1016/j.mechmat.2025.105394","DOIUrl":"10.1016/j.mechmat.2025.105394","url":null,"abstract":"<div><div>The ability to conduct digital volume correlation (DVC) in nominally homogeneous metals using X-ray computed tomography (XCT) is examined by a combination of synthetic and experimental techniques. DVC requires markers to track within the volume and we first discuss methods by which the grayscale variations due to inherent inhomogeneities in nominally homogeneous metals can be enhanced in X-ray scans. Using these enhanced scans we then validate the predictions of the DVC algorithm via a combination of synthetically imposed rigid motions and complex displacement fields. The rigid body motions are captured very easily as the fields are dominated by motion of the specimen boundaries where a high grayscale contrast exists between the metal and air. The local deformation fields where there is no boundary motion require high quality tomographic scans, and we explore the range of hyperparameters that give high fidelity predictions. The study is then extended to real displacement fields obtained from experiments. A key conclusion is that hyperparameters optimised by imposing synthetic displacement fields are often inappropriate. This is because the changes to the image grayscales that occur due to the actual deformation of metals are different from those assumed in the algorithms used to impose synthetic deformations. Using a combination of different specimen geometries and known physical behaviour of the specimens, we reoptimise the hyperparameters in a global DVC algorithm that naturally uses boundary information. Finally, we also explore “hardware” methods to improve the DVC predictions. Our results show promise and suggest routes for further improvements.</div></div>","PeriodicalId":18296,"journal":{"name":"Mechanics of Materials","volume":"207 ","pages":"Article 105394"},"PeriodicalIF":3.4,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}