N. Shen , R.Z. Zhang , Z.X. Xia , Y. Cong , S.T. Gu , Z.-Q. Feng
{"title":"Vibration bandgap of immersed periodic plates with fluid surface sloshing effect","authors":"N. Shen , R.Z. Zhang , Z.X. Xia , Y. Cong , S.T. Gu , Z.-Q. Feng","doi":"10.1016/j.jsv.2025.119499","DOIUrl":"10.1016/j.jsv.2025.119499","url":null,"abstract":"<div><div>This study extends our previous work by implementing a unit cell-based symmetric fluid–structure formulation to predict vibration bandgaps in immersed periodic composite plates, with the account for fluid surface sloshing effects. The novelty lies in integrating Bloch periodic boundary conditions into a symmetric hydro-elastic <span><math><mrow><mo>(</mo><mi>u</mi><mo>,</mo><mi>η</mi><mo>,</mo><mi>φ</mi><mo>)</mo></mrow></math></span> unit cell model with fluid–structure interaction (FSI). The unit cell comprises three subdomains: the immersed composite plate, the fluid, and the fluid free surface. Bloch periodic conditions are applied across all subdomains, enabling bandgap predictions that incorporate the combined effects of fluid inertia and surface sloshing. Hence, the approach accounts for full-range immersion depths ranging from deep submersion to near-surface scenarios. The numerical cases investigate an immersed periodic plate with square inclusions, revealing a competition between fluid inertia and surface sloshing in influencing the structure’s vibration dynamics. Specifically, fluid inertia dominates in deeply immersed conditions, whereas surface sloshing prevails in shallow immersion. The observation is validated by comparing with frequency response analysis performed under equivalent FSI conditions. Additionally, the method is applied to explore dispersive bandgaps in microstructures with anisotropic wave propagation. The results underline the effectiveness of the proposed model in designing immersed meta-structures for vibration mitigation.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"622 ","pages":"Article 119499"},"PeriodicalIF":4.9,"publicationDate":"2025-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145365112","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}
{"title":"Interface reduced substructuring using polynomials for non-smooth line-like interfaces","authors":"Jon Young, Andrew Wixom","doi":"10.1016/j.jsv.2025.119502","DOIUrl":"10.1016/j.jsv.2025.119502","url":null,"abstract":"<div><div>A method for reducing the interface degrees of freedom on a substructure by means of polynomial basis vectors is developed for interfaces composed of distinct edges and corners. The scope is restricted to interfaces with straight line geometry. Two sets of polynomials are utilized to enforce compatibility at corners where two edges meet. The first set accounts for motion at the corners and are referred to as corner polynomials, and the second accounts for higher frequency motion allowing each edge to move independently of the others, referred to as edge polynomials. Due to the interface motion being described by an identical set of basis vectors on adjacent substructures, coupling along interfaces with incompatible meshes is possible without significant loss in the accuracy of dynamic properties of the assembly. This interface reduction technique is discussed in the framework of creating an assembly from copies of a parent substructure, in which the parent substructure has reduced internal and interface degrees of freedom and is then translated and rotated into a larger assembly. The reduced basis is demonstrated on several plate substructures, and shown to provide accurate estimates of the assembly’s dynamic properties. This accuracy increases proportionally with the number of basis vectors used to describe the interface motion, but can deteriorate if the order of the basis polynomials chosen cannot be resolved by the interface mesh.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"623 ","pages":"Article 119502"},"PeriodicalIF":4.9,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145334908","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}
Liyuan Qi , Kai Zhang , Yizhu He , Xianghui Cao , Zichen Deng
{"title":"Dynamic and wave propagation characteristics of the regular hexagonal prism modular tensegrity structure","authors":"Liyuan Qi , Kai Zhang , Yizhu He , Xianghui Cao , Zichen Deng","doi":"10.1016/j.jsv.2025.119501","DOIUrl":"10.1016/j.jsv.2025.119501","url":null,"abstract":"<div><div>Tensegrity structure is one of the ideal structural form to realize modular assembly of large spacecraft. Understanding the dynamic characteristics of modular tensegrity structures such as natural frequencies, vibration modes and wave behavior is crucial for the successful deployment of spacecraft in space. In this paper, according to the engineering practice of spacecraft assembly, we choose a regular hexagonal tensegrity structure module, and establish the dynamic model of tensegrity structure based on Lagrangian equation by finite element method and node coordinate vector. Subsequently, the natural frequencies and vibration modes of the modular tensegrity structure during the expansion process are analyzed. It is found that as the number of modules increases, the natural frequency tends to decrease and the torsional mode is more likely to occur. In addition, a comparison is made between the isotropic solid circular plate structure and the tensegrity structure, focusing on differences in modes and frequencies. The influence of self-stress on the modal characteristics and natural frequencies of tensegrity structures with varying numbers of modules is also investigated. Furthermore, according to the Bloch's theorem and the dynamic model, a wave propagation model for the tensegrity structure module units is established, from which the band structure and group velocity are derived. By comparing these results with the wave propagation paths obtained from numerical simulations of the large space tensegrity structure, it is demonstrated that the wave behavior of the large space tensegrity structure can be obtained by analyzing the wave characteristics of the module unit. Moreover, it is revealed that the regular hexagonal prism tensegrity structure exhibits difficulty in transmitting transverse waves and possesses a unique wave propagation directionality.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"622 ","pages":"Article 119501"},"PeriodicalIF":4.9,"publicationDate":"2025-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145365157","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}
{"title":"Improved stability estimates and flight time predictions using higher-order transverse discontinuity mapping in hybrid dynamical systems","authors":"Rohit Chawla, Aasifa Rounak, Vikram Pakrashi","doi":"10.1016/j.jsv.2025.119497","DOIUrl":"10.1016/j.jsv.2025.119497","url":null,"abstract":"<div><div>This article emphasizes on inconsistencies in the dynamical estimates obtained by first-order transverse discontinuity mapping (TDM) and direct numerical observations for hybrid dynamical systems. Pitfalls of locally linearizing hybrid nonlinear dynamical systems near discontinuity boundaries are demonstrated along with examples of how such linearization could lead to incorrect estimates of impact occurrences for transverse interactions with a rigid barrier. A higher-order TDM is proposed to overcome this shortcoming, allowing for better analytical estimation of impact occurrence times, state transitions, and, consequently, the evolution of trajectories. The difference in flight times of two closely initiated trajectories in the local neighbourhood of a discontinuity boundary is estimated up to <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span>. The resulting quadratic equation implies that the orbits local to the impacting state, corresponding to a negative discriminant, will not reach the discontinuity boundary. Further, the <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mn>2</mn><mo>)</mo></mrow></mrow></math></span> correction terms to the analytical expression of the TDM ensure that the flight time estimates do not diverge for low-velocity impacts near grazing, thereby avoiding overestimation of the mapped state. A numerical method is subsequently developed to estimate a saltation matrix incorporating the proposed higher-order TDM to avoid incorrect impact occurrences. Modifications to the existing algorithms used to numerically quantify local stability, namely the Lyapunov spectra and Floquet multipliers, are proposed. Stability analyses using the proposed higher-order approach are carried out for representative cases of a hard impact oscillator and a pair impact oscillator, with results consistent with numerically obtained bifurcation diagrams.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"622 ","pages":"Article 119497"},"PeriodicalIF":4.9,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145334468","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}
{"title":"Harnessing von Kármán nonlinearity for load-adaptive metadampers","authors":"Rohit Sinha , Shuvajit Mukherjee , Sondipon Adhikari , Saikat Sarkar","doi":"10.1016/j.jsv.2025.119496","DOIUrl":"10.1016/j.jsv.2025.119496","url":null,"abstract":"<div><div>Mechanical metamaterials offer unprecedented control over wave propagation through engineered microstructures. Yet their behaviour under geometric nonlinearity and damping remains insufficiently explored. This study investigates how <em>von</em> Kármán nonlinearity, combined with damping, can be harnessed as a design mechanism to dynamically tune wave characteristics in periodic lattice-based metamaterials. Through nonlinear finite element simulations on regular and re-entrant hexagonal lattices subjected to distributed compressive loads, we examine changes in their band gap behaviour and deformation responses. By incorporating quadratic eigenvalue solutions, transmission losses, and iso-frequency maps, the research shows that geometric nonlinearity and damping fundamentally alter wave propagation. Under increased loading, existing band gaps diminish while new ones emerge at higher frequencies. This is accompanied by a systematic leftward and downward shift in band gap evolution due to nonlinearity and damping, respectively. Metadamping arises from the interplay between lattice geometry, nonlinearity, and damping configuration, enabling frequency-selective and load-adaptive dissipation. The study also shows that the apparent Poisson-like parameter displays nonlinear dependence on loading, reflecting microstructural deformations, and serving as an order parameter to characterise and tune auxetic behaviour in lattice metamaterials. Importantly, the applicability of Bloch’s theorem is validated in geometrically nonlinear and damped systems, extending its relevance to deformed metamaterial structures. These insights demonstrate that geometric nonlinearity and damping, rather than being limitations, can be harnessed as tunable design parameters. This work opens new directions for the development of load-adaptive metamaterials with dynamically adjustable wave-filtering and dissipation capabilities, offering broad utility in vibration control, acoustic manipulation, and impact mitigation.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"621 ","pages":"Article 119496"},"PeriodicalIF":4.9,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333041","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}
{"title":"Dynamic interactions in spalled bearings: A coupled friction-IAS model for fault-induced torsional vibrations","authors":"Chao Li , Yu Guo , Xin Chen","doi":"10.1016/j.jsv.2025.119495","DOIUrl":"10.1016/j.jsv.2025.119495","url":null,"abstract":"<div><div>Instantaneous angular speed (IAS)-based condition monitoring has emerged as a significant research topic since it offers advantages of short transfer paths, no periodic calibration, etc. However, the contribution of complex friction to IAS perturbations has not yet been effectively elaborated. The torsional vibration analysis of the IAS perturbation of bearings is usually simplified as the coupling of normal and tangential force in previous works. To address this issue, this study proposes a comprehensive dynamic model of a ball bearing with a localized spall on its outer race. Firstly, a method for calculating the time-varying friction moment considering the elastic hysteresis of raceway material, the differential sliding friction between ball and raceway, and the viscous resistance caused by lubrication is proposed. Secondly, the interactions of friction moments and the localized spall are introduced, which further elaborates on the influence of friction factors on IAS signal perturbation. Finally, simulation and experimental results validate the proposed model, and the effects of localized spalls on IAS signals on the IAS signals and the friction moments are analyzed. The detectability of the IAS signal is also discussed under different shaft speeds and external loads.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"621 ","pages":"Article 119495"},"PeriodicalIF":4.9,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333037","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}
{"title":"Estimation of multiple sound sources by inverting one eigenpair of cross-spectral matrix with dimensionality reduction","authors":"Jianing Li , Xun Wang , Jérôme Antoni","doi":"10.1016/j.jsv.2025.119490","DOIUrl":"10.1016/j.jsv.2025.119490","url":null,"abstract":"<div><div>This paper addresses the problem of identifying multiple sound sources from pressure signals measured by a microphone array. The proposed method uses only one eigenvalue and the associated eigenvector of the cross-spectral matrix (CSM) to match their theoretical model to estimate the locations and powers of multiple sound sources, which ends up with searching the zeros of only <span><math><mrow><mi>S</mi><mo>+</mo><mn>1</mn></mrow></math></span> equations (<span><math><mi>S</mi></math></span> is the number of sources). This is possible because (i) we find an alternative <span><math><mi>S</mi></math></span>-by-<span><math><mi>S</mi></math></span> matrix of the <span><math><mi>M</mi></math></span>-by-<span><math><mi>M</mi></math></span> CSM (<span><math><mi>M</mi></math></span> is the number of microphones and <span><math><mrow><mi>M</mi><mo>≫</mo><mi>S</mi></mrow></math></span>) in the sense of having identical eigenvalues and equivalent eigenvectors; (ii) we prove that each eigenvalue and eigenvector pair of the CSM or its dimension-reduced alternative uniquely decides all the sound source parameters. As a result, the proposed method can accurately estimate all the parameters of multiple sound sources with super-resolution and it is easy to solve without any optimization problems, which are demonstrated via both numerical and experimental data.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"621 ","pages":"Article 119490"},"PeriodicalIF":4.9,"publicationDate":"2025-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333039","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}
{"title":"Experimental study of the aeroacoustic behavior of a pitching NACA65-410 airfoil","authors":"Esmaeel Masoudi , Bin Zang , Mahdi Azarpeyvand","doi":"10.1016/j.jsv.2025.119494","DOIUrl":"10.1016/j.jsv.2025.119494","url":null,"abstract":"<div><div>This study experimentally investigates a NACA65-410 cambered airfoil undergoing oscillating pitching motions at a chord-based Reynolds number of <span><math><mrow><msub><mrow><mi>Re</mi></mrow><mrow><mi>c</mi></mrow></msub><mo>=</mo><mn>4</mn><mo>.</mo><mn>2</mn><mo>×</mo><mn>1</mn><msup><mrow><mn>0</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math></span>. Two reduced frequencies, <span><math><mrow><msub><mrow><mi>k</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>023</mn></mrow></math></span> and <span><math><mrow><msub><mrow><mi>k</mi></mrow><mrow><mi>r</mi></mrow></msub><mo>=</mo><mn>0</mn><mo>.</mo><mn>052</mn></mrow></math></span>, were tested. Results show that increasing the pitching amplitude and frequency leads to higher far-field noise. Surface pressure fluctuations are generally comparable or higher in the pitching cases compared to static case, except in deep stall where the static cases showed stronger fluctuations. Phase-averaged surface pressure spectrograms reveal significant differences between dynamic and static cases, with four distinct flow regimes emerging around stall onset and flow reattachment. These regimes are sensitive to <span><math><msub><mrow><mi>k</mi></mrow><mrow><mi>r</mi></mrow></msub></math></span>, mean angle of attack, and pitching amplitude, while maintaining consistent characteristics. Asymmetric behavior in surface pressure fluctuations and overall sound pressure level is observed, particularly at higher <span><math><msub><mrow><mi>k</mi></mrow><mrow><mi>r</mi></mrow></msub></math></span>. Coherence maps along the chordwise direction reveal an increase in coherence at higher angles of attack, which further intensifies as flow separates from the airfoil, where the convecting structures to the downstream dominate the flow. These findings are crucial for advancing the design and noise mitigation strategies of airfoils in applications such as rotorcraft, wind turbines, and unmanned aerial vehicles, where dynamic stall and associated acoustic emissions impact performance and environmental compliance.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"621 ","pages":"Article 119494"},"PeriodicalIF":4.9,"publicationDate":"2025-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333051","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}
{"title":"Far-Field Aeroacoustic Shape Optimization using Large Eddy Simulation","authors":"Mohsen Hamedi, Brian C. Vermeire","doi":"10.1016/j.jsv.2025.119492","DOIUrl":"10.1016/j.jsv.2025.119492","url":null,"abstract":"<div><div>This study presents a shape optimization framework that combines a Flux Reconstruction (FR) spatial discretization, Large Eddy Simulation (LES), the Ffowcs-Williams and Hawkings (FW-H) formulation, and the gradient-free Mesh Adaptive Direct Search (MADS) optimization algorithm. We emphasize the necessity of duplicating the data surface to achieve accurate far-field noise prediction in spanwise periodic problems using the FW-H formulation. The proposed parallel implementation of the optimization framework ensures consistent runtime per optimization iteration, regardless of the number of design parameters, thereby addressing a common limitation of many gradient-free algorithms. The framework is demonstrated through far-field aeroacoustic shape optimization of NACA 4-digit airfoils at a Reynolds number of 23,000. The objective function minimizes the Overall Sound Pressure Level (OASPL) at a far-field observer positioned 10 unit chords below the trailing edge, while preserving the mean lift coefficient and reducing the mean drag coefficient. The optimized airfoil achieves an OASPL reduction of <span><math><mrow><mn>5</mn><mo>.</mo><mn>9</mn><mspace></mspace><mi>dB</mi></mrow></math></span> and over 14% decrease in mean drag, while maintaining the mean lift coefficient. These results underscore the feasibility and effectiveness of the proposed approach for practical shape optimization applications.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"621 ","pages":"Article 119492"},"PeriodicalIF":4.9,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145267764","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}
{"title":"Transmission loss limitations of embedded acoustic black holes","authors":"Jie Deng , Oriol Guasch , Laurent Maxit","doi":"10.1016/j.jsv.2025.119493","DOIUrl":"10.1016/j.jsv.2025.119493","url":null,"abstract":"<div><div>Acoustic black hole (ABH) indentations in beams and plates are known to reduce vibrations and sound radiation above their cut-on frequency, <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>cut−on</mi></mrow></msub></math></span>. However, their effect on transmission loss between cavities has not been fully explored. This study presents a two-dimensional model, representative of a three-dimensional case, that demonstrates that when the ABH cut-on frequency <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>cut−on</mi></mrow></msub></math></span> is lower than the plate’s critical frequency <span><math><msub><mrow><mi>f</mi></mrow><mrow><mi>crit</mi></mrow></msub></math></span>, an ABH beam can underperform a uniform one in the frequency range <span><math><mrow><msub><mrow><mi>f</mi></mrow><mrow><mi>cut−on</mi></mrow></msub><mo><</mo><mi>f</mi><mo><</mo><msub><mrow><mi>f</mi></mrow><mrow><mi>crit</mi></mrow></msub></mrow></math></span>, leading to lower transmission loss. It is demonstrated that this counterintuitive behavior is linked to the excitation of different types of global modes in the coupled system (Source cavity - ABH beam - Receiver cavity) and to low-frequency non-resonant modes in the ABH beam, which lie in the radiation domain and inhibit the ABH effect. As a result, the acoustic pressure in the receiver cavity becomes higher compared to that for a uniform beam partition. The two-dimensional model is analyzed using a Rayleigh–Ritz formulation that couples the beam’s bending displacement to the acoustic particle displacement in the cavities. Natural boundary and traction continuity conditions are imposed weakly, while essential and displacement continuity conditions are enforced using the nullspace method, thus avoiding explicit coupling matrices.</div></div>","PeriodicalId":17233,"journal":{"name":"Journal of Sound and Vibration","volume":"620 ","pages":"Article 119493"},"PeriodicalIF":4.9,"publicationDate":"2025-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145321081","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}