Journal of The Mechanics and Physics of Solids最新文献_第3页

A discrete–continuous model of coupled plasticity and fracture

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-21 DOI: 10.1016/j.jmps.2025.106044

Zhangtao Li , Zhuo Zhuang , Zhijie Li , Tao Wang , Zhanli Liu , Yinan Cui

{"title":"A discrete–continuous model of coupled plasticity and fracture","authors":"Zhangtao Li , Zhuo Zhuang , Zhijie Li , Tao Wang , Zhanli Liu , Yinan Cui","doi":"10.1016/j.jmps.2025.106044","DOIUrl":"10.1016/j.jmps.2025.106044","url":null,"abstract":"<div><div>Understanding the interplay between plasticity and fracture is the basis for the prediction and design of materials and structures, which is controlled by the concurrent dynamics of discrete dislocations and cracks. However, till now, how to directly capture the co-evolution of a three-dimensional (3D) discrete dislocation network and arbitrary crack remains challenging due to their intrinsic complex interactions and different modeling frameworks. To overcome these issues, we proposed a discrete–continuous coupled plasticity–fracture model in a thermodynamic consistent framework, which can not only reproduce the discrete crack–dislocation interdependence dynamics, but also demonstrate capability and flexibility in handling complex boundary value problems by simultaneously considering the co-evolution of continuous plasticity and fracture field. This model offers many advantages, including accurately capturing the image force of the crack surface on dislocation, the shielding and anti-shielding effect of 3D dislocation on crack propagation, as well as reproducing arbitrary crack propagation without reliance on a predefined crack path. As a representative example, a notched microbeam bending problem is studied and compared with experiments, yielding new insights regarding the 3D co-evolution of collective defects and their influence on mechanical response.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"197 ","pages":"Article 106044"},"PeriodicalIF":5.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Indentation on a constrained electroactive gel

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-21 DOI: 10.1016/j.jmps.2025.106045

Guozhan Xia

{"title":"Indentation on a constrained electroactive gel","authors":"Guozhan Xia","doi":"10.1016/j.jmps.2025.106045","DOIUrl":"10.1016/j.jmps.2025.106045","url":null,"abstract":"<div><div>Electroactive gel (EAG), a smart material with tunable physical properties, has attracted increasingly more attention in various engineering fields. This paper presents the analytical solutions for the frictionless contact between a rigid spherical indenter and a block of constrained swollen EAG, which is also subject to a transverse electric field. The classical JKR model is extended to involve the additional energy penalty accounting for surface tension in the equilibrium state. With the new results in surface Green's function established in advance for electromechanical orthotropic materials, typical indentation relations are derived in terms of elementary functions for electrically conducting and insulating cases, respectively. The whole analysis is performed based on the gel endowed with a Flory-Rehner energy density function to signify the feasibility of our method. The theoretical predictions are first verified by comparing to the finite element simulations, and then focus on the influences of biasing fields on the indentation relations and the geometric characteristics during contact, including the eccentricity, the pull-out force, and the relevant critical distance at beginning of separation. It is noteworthy that the disappearance of indentation force does not necessarily correspond to the initiation of surface instability for the orthotropic material, which may attribute to the absence of external Maxwell stress. A novel critical criterion with a more comprehensive form is proposed instead to not only cover the traditional perspective but also be applicable for more general cases. We believe that the contact model proposed here serves a theoretical base for the indentation-based characterization method of EAGs and a wide range of kindred functional soft materials.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"197 ","pages":"Article 106045"},"PeriodicalIF":5.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Approximating arbitrary traction–separation-laws by means of phase-field theory — Mathematical foundation and numerical implementation

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-20 DOI: 10.1016/j.jmps.2025.106038

H. Lammen , S. Conti , J. Mosler

{"title":"Approximating arbitrary traction–separation-laws by means of phase-field theory — Mathematical foundation and numerical implementation","authors":"H. Lammen , S. Conti , J. Mosler","doi":"10.1016/j.jmps.2025.106038","DOIUrl":"10.1016/j.jmps.2025.106038","url":null,"abstract":"<div><div>Cohesive zone models are powerful for capturing non-linear material failure. In contrast to classic bulk material models, they are based on so-called traction–separation-laws – relations connecting the stress vector acting at an interface (e.g., at the crack) to its energetically dual variable being the displacement jump (e.g., opening of the crack). A major drawback of cohesive zone models is that they are characterized by free boundary problems, i.e., the geometry of the crack is not known beforehand, but part of the solution. In order to eliminate this problem and to avoid the numerically expensive tracking of the evolving cracks, phase-field approximations of cohesive zone models have been developed. Within these approximations, the degradation function reducing the stiffness of the pristine material implicitly defines the traction–separation law. A mathematically rigorous phase-field approximation of cohesive zone models was elaborated in (Conti et al., 2016). In this paper, a new family of degradation functions in line with the framework (Conti et al., 2016) is advocated. Based on an inverse optimization problem, this degradation function is identified such that it leads to a desired traction–separation-law including exponential softening, linear softening and bilinear softening. Phase-field simulations and their comparison to the underlying sharp interface problems will highlight the capabilities of the proposed framework.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"197 ","pages":"Article 106038"},"PeriodicalIF":5.0,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143071670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Snap-through instability-driven enhancement of magnetoelectric coupling in soft electrets

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-19 DOI: 10.1016/j.jmps.2025.106043

Kai Tan , Lingling Chen , Shengyou Yang , Qian Deng

{"title":"Snap-through instability-driven enhancement of magnetoelectric coupling in soft electrets","authors":"Kai Tan , Lingling Chen , Shengyou Yang , Qian Deng","doi":"10.1016/j.jmps.2025.106043","DOIUrl":"10.1016/j.jmps.2025.106043","url":null,"abstract":"<div><div>Conventional magnetoelectric (ME) systems often suffer from the reduced conversion efficiency at low frequencies due to the low power input and relatively small ME coupling coefficient, constraining their applications in magnetic sensing and energy harvesting. In this work, we present a novel approach of utilizing the snap-through instability of soft ME materials to enhance their electric responses in low-frequency magnetic environments. This snapping soft ME material, also called the snapping ME electret (SMEE), is designed as an elastomeric arch with tunable residual magnetic flux density and embedded net charges. The high performance of SMEEs stems from fact that, when staying at a critical instability state, any small magnetic perturbation would induce the snap-through behavior of it and generate high-frequency electrical pulses. Here, a theoretical model based on the instability mechanics of SMEEs is presented and used to predict the strong ME coupling effect near its critical state. Experiments are also conducted to confirm the enhanced ME coupling of SMEEs across a broad range at extremely low frequencies. The SMEE proposed here demonstrates an interesting and effective mechanical pathway to amplify and tune the coupling between magnetic and electric fields.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106043"},"PeriodicalIF":5.0,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

3D phase-field cohesive fracture: Unifying energy, driving force, and stress criteria for crack nucleation and propagation direction

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-17 DOI: 10.1016/j.jmps.2025.106036

Ye Feng , Lu Hai

{"title":"3D phase-field cohesive fracture: Unifying energy, driving force, and stress criteria for crack nucleation and propagation direction","authors":"Ye Feng , Lu Hai","doi":"10.1016/j.jmps.2025.106036","DOIUrl":"10.1016/j.jmps.2025.106036","url":null,"abstract":"<div><div>This paper presents a 3D variational phase-field cohesive fracture model that incorporates crack direction information into the energy functional. Through an analytical homogenization procedure, the crack normal is obtained in closed form based on the principle of energy minimization. We find that, within the proposed model, several widely recognized crack direction criteria—including the minimum potential energy, maximum driving force, and maximum cohesive stress—are consistent and unified. The remaining criteria are simply stress-space descriptions of the same physical state, derived from the strain-space minimum potential energy criterion through the Legendre transformation. The performance of the proposed model is demonstrated through four representative numerical examples involving tension, torsion, anti-plane shear, and mixed-mode loading. The results indicate that, as the proposed model faithfully converges to the 3D cohesive zone model with a mixed-mode cohesive law, it is capable of predicting complex 3D crack morphologies during nucleation and growth, and is general enough to describe both tensile- and shear-dominated 3D fractures.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106036"},"PeriodicalIF":5.0,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Hydromechanical field theory of plant morphogenesis 植物形态发生的流体力学场理论

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-15 DOI: 10.1016/j.jmps.2025.106035

Hadrien Oliveri , Ibrahim Cheddadi

{"title":"Hydromechanical field theory of plant morphogenesis","authors":"Hadrien Oliveri , Ibrahim Cheddadi","doi":"10.1016/j.jmps.2025.106035","DOIUrl":"10.1016/j.jmps.2025.106035","url":null,"abstract":"<div><div>The growth of plants is a hydromechanical phenomenon in which cells enlarge by absorbing water, while their walls expand and remodel under turgor-induced tension. In multicellular tissues, where cells are mechanically interconnected, morphogenesis results from the combined effect of local cell growths, which reflects the action of heterogeneous mechanical, physical, and chemical fields, each exerting varying degrees of nonlocal influence within the tissue. To describe this process, we propose a physical field theory of plant growth. This theory treats the tissue as a <em>poromorphoelastic</em> body, namely a growing poroelastic medium, where growth arises from pressure-induced deformations and osmotically-driven imbibition of the tissue. From this perspective, growing regions correspond to hydraulic sinks, leading to the possibility of complex non-local regulations, such as water competition and growth-induced water potential gradients. More in general, this work aims to establish foundations for a mechanistic, mechanical field theory of morphogenesis in plants, where growth arises from the interplay of multiple physical fields, and where biochemical regulations are integrated through specific physical parameters.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106035"},"PeriodicalIF":5.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142989293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The impacts of thermoelastic anisotropy and grain boundary misorientation on microcracking in ceramics

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-14 DOI: 10.1016/j.jmps.2024.106024

Andrew R. Ericks, Frank W. Zok, Daniel S. Gianola, Matthew R. Begley

{"title":"The impacts of thermoelastic anisotropy and grain boundary misorientation on microcracking in ceramics","authors":"Andrew R. Ericks, Frank W. Zok, Daniel S. Gianola, Matthew R. Begley","doi":"10.1016/j.jmps.2024.106024","DOIUrl":"10.1016/j.jmps.2024.106024","url":null,"abstract":"<div><div>This paper examines the role of thermoelastic anisotropy on grain boundary cracking in brittle materials using a highly efficient computational framework. Energy release rates (ERRs) are computed for 35 materials spanning all seven crystal systems. Two crack geometries are considered: short interface cracks in isolated bicrystal plates, and cracked grain boundaries in polycrystal plates comprising periodic hexagonal grains. Crack driving forces are computed for penetration through the plate thickness (for cracks of width equal to the length of a hexagonal grain boundary), extension along bicrystal interfaces, transgranular cracks that emerge from triple junctions, and kinking into bulk materials and at grain triple junctions. The high throughput computational framework produces probability distributions for ERRs arising from randomly oriented grains; the distributions for cracks at grain edges in polycrystals are broader than those for short cracks along bicrystal interfaces. A broad study of different grain configurations also illustrates that only the first 5-6 rings of neighboring grains influence crack driving forces for a given interface. The implications for interpreting microcracking observations, quantifying the performance of textured ceramics, and designing two-phase ceramic composites are briefly discussed.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106024"},"PeriodicalIF":5.0,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining 基于梯度增强的应力状态相关韧性损伤模型——以接合为例

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-13 DOI: 10.1016/j.jmps.2025.106026

Johannes Friedlein, Julia Mergheim, Paul Steinmann

{"title":"Modelling of stress-state-dependent ductile damage with gradient-enhancement exemplified for clinch joining","authors":"Johannes Friedlein, Julia Mergheim, Paul Steinmann","doi":"10.1016/j.jmps.2025.106026","DOIUrl":"10.1016/j.jmps.2025.106026","url":null,"abstract":"<div><div>A coupled finite plasticity ductile damage and failure model is proposed for the finite element simulation of clinch joining, which incorporates stress-state dependency and regularisation by gradient-enhancement of the damage variable. Ductile damage is determined based on a failure indicator governed by a failure surface in stress space. The latter is exemplary chosen as a combination of the Hosford–Coulomb and Cockcroft–Latham–Oh failure criteria for the high and low stress triaxiality range, respectively, to cover the wide stress range encountered in forming. Damage is coupled to elasto-plasticity to capture the damage-induced degradation of the stiffness and flow stress. This affects the material behaviour up to failure, thereby realistically altering the stress state. Consequently, especially for highly ductile materials, where substantial necking and localisation precede material fracture, the failure prediction is enhanced. The resulting stress softening is regularised by gradient-enhancement to obtain mesh-objective results. The analysis of a modified punch test experiment emphasises how the damage-induced softening effect can strongly alter the actual stress state towards failure. Moreover, the impact of successful regularisation is shown, and the applicability of the damage and failure model to clinch joining is proven.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106026"},"PeriodicalIF":5.0,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142989295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fire-induced damage behaviour in corrosion-damaged concrete: Thermal-mechanical coupling phase field meso-scale modeling 腐蚀损伤混凝土的火致损伤行为：热力-力学耦合相场细观尺度模拟

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-13 DOI: 10.1016/j.jmps.2025.106041

Kunting Miao , Zichao Pan , Xurui Fang , Airong Chen

{"title":"Fire-induced damage behaviour in corrosion-damaged concrete: Thermal-mechanical coupling phase field meso-scale modeling","authors":"Kunting Miao , Zichao Pan , Xurui Fang , Airong Chen","doi":"10.1016/j.jmps.2025.106041","DOIUrl":"10.1016/j.jmps.2025.106041","url":null,"abstract":"<div><div>The mechanical performance degradation of concrete in marine environments is often caused by multi-hazard, such as long-term environmental loads and short-term extreme loads, which also lead to more complex damage pattern. This study presents a thermal-mechanical coupling phase field meso‑scale model to simulate the damage evolution process of concrete subjected to rebar corrosion and fire hazards. This model employed a fracture phase-field model to characterize damage progression in concrete and utilized thermal expansion strain, temperature-dependent material property phase field-dependent thermal conductivity to realize the coupling of temperature field, mechanical field, and phase field. We validated the proposed model with examples of concrete fracture, fire-induced damage and fire-induced mechanical property degradation. Subsequently, we simulated the fire-induced damage in corrosion-damaged concrete with varying corrosion-induced damage extents and aggregate volume fractions, which involves two steps: (1) simulation of damage induced by corrosion; (2) utilizing results as initial conditions for subsequent simulation of fire-induced damage. Simulation results indicate that fire-induced damage originates in the interfacial transition zone and propagates radially, ultimately resulting in a failure pattern of mesh cracks and local spalling. The corrosion-induced damage extent influences the fire-induced damage evolution process, spalling location and fire-induced damage extent, while the aggregate volume fraction primarily affects damage extent. Finally, we further researched and compared the fire-induced damage of corrosion-damaged concrete with one middle rebar, one corner rebar and multiple rebars.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106041"},"PeriodicalIF":5.0,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142989294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanobiological modeling of viscoelasticity in soft tissue growth and morphogenesis

IF 5 2区工程技术

Journal of The Mechanics and Physics of Solids Pub Date : 2025-01-13 DOI: 10.1016/j.jmps.2025.106032

Zhongya Lin , Weizhi Huang , Shuang Li , Mingfeng Wang , Jinshuai Bai , Xindong Chen , Xi-Qiao Feng

{"title":"Mechanobiological modeling of viscoelasticity in soft tissue growth and morphogenesis","authors":"Zhongya Lin , Weizhi Huang , Shuang Li , Mingfeng Wang , Jinshuai Bai , Xindong Chen , Xi-Qiao Feng","doi":"10.1016/j.jmps.2025.106032","DOIUrl":"10.1016/j.jmps.2025.106032","url":null,"abstract":"<div><div>Most soft biological tissues feature distinct mechanical properties of viscoelasticity, which play a significant role in their growth, development, and morphogenesis. In this paper, we propose a mechanobiological viscoelastic model in the framework of thermodynamics. The multiscale mechanisms underlying the viscoelasticity of tissues are clarified, such as extracellular matrix composition and organization, cell types and states, dynamic cell–matrix and cell–cell interactions, and active cytoskeleton evolution. This model enables us to elucidate how viscoelastic effects modulate the growth and surface instability of soft tissues via coupled mechano-chemo-biological regulatory mechanisms. The proposed constitutive model is implemented into the finite element method, to explore the growth, stability, and morphological evolution of tissues. Illustrative examples, including tumor growth and organoid development, demonstrate that viscoelasticity can facilitate sustained tissue growth, and significantly influences the critical conditions of surface wrinkling and the morphological evolution of tissues. The results are consistent with relevant experimental observations. This study provides a theoretical model for growing soft tissues with viscoelastic effects, and holds promise for potential applications in clinical diagnosis and treatment of some diseases.</div></div>","PeriodicalId":17331,"journal":{"name":"Journal of The Mechanics and Physics of Solids","volume":"196 ","pages":"Article 106032"},"PeriodicalIF":5.0,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143031437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0