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  • LI Zhenhai, LI Jing
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    Specific recognition of peptide-major histocompatibility complex (pMHC) by the T cell receptor (TCR) is central to the initiation of adaptive immune responses. Although traditional structural biology approaches have resolved the structures of TCR-pMHC complexes, static structures alone are insufficient to reveal the dynamic recognition mechanisms driven by thermal fluctuations or mechanical forces under physiological conditions. Molecular dynamics simulations, based on Newton's laws, provide a powerful approach for characterizing the dynamic behavior of TCR-pMHC complexes. This review summarizes recent advances in the application of molecular dynamics simulations to TCR recognition studies, focusing on the roles of interfacial conformational dynamics in shaping antigen specificity. Furthermore, we discuss recent progress in understanding force-driven catch bond formation and coreceptor-mediated regulation during TCR recognition.
  • LI Kaiwen, ZHAO Yinbo, LI Yan
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    Carbon fiber reinforced polymer composites (CFRPs) are widely used in aerospace, rail transportation, and advanced equipment manufacturing. During curing, thermosetting resins undergo chemical crosslinking, network evolution, and volume changes, which strongly affect cure-induced deformation, residual stress, interfacial bonding, and service reliability. Conventional macroscopic models are insufficient to capture the cross-scale transfer from atomic-scale reaction mechanisms to structural performance. This paper reviews multiscale modeling advances for CFRP matrix resin curing, including density functional theory (DFT), molecular dynamics (MD), coarse-grained/dissipative particle dynamics (CG/DPD), and machine learning (ML). Their roles in reaction analysis, crosslinked network construction, thermophysical and mechanical property prediction, mesoscale characterization, and data-driven optimization are summarized.
  • WEN Shijie, LIU Yongqi, NIE Guohua
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    A unified path description method, an equivalent continuum model based on the smeared stiffness method, and a numerical solution framework combining circumferential modal decomposition with the differential quadrature method are established for the buckling and free vibration analysis of lattice conical shells with different helical rib paths. The geodesic path, equal-stiffness path, and hybrid paths are incorporated into the same parametric formulation, and the theoretical results are compared with finite element models based on triangular and Kagome unit-cell configurations. The results show that the proposed method can accurately capture the variations in the critical buckling load and fundamental frequency with the path and structural parameters, and provides higher prediction accuracy for the fundamental frequency. Parametric analyses further indicate that the applicability of the proposed model is jointly affected by the grid density, rib sectional dimensions, and conical-shell geometry. The triangular unit-cell model shows stable overall prediction accuracy, whereas the Kagome unit-cell model provides accurate fundamental-frequency predictions but larger buckling errors for slender configurations or low grid densities.
  • WANG Dong, LIU Tao, YANG Deqing, LI Zhimin
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    Local resonance (LR) metamaterials exhibit unique bandgap characteristics, showing great potential for vibration control in fields such as mechanical manufacturing and aerospace. Among them, multi-resonance unit metamaterials demonstrate excellent performance in low-frequency broadband vibration suppression due to bandgap coupling effects. However, traditional design methods often rely on experience-based practices, making it difficult to capture their complex physical phenomena and achieve targeted bandgap generation. This study proposes an inverse design method of multi-resonance unit LR metamaterials using a physics-informed convolutional neural network (PINN). First, a new phononic crystal configuration is designed, and a corresponding physical equivalent model is established to evaluate the local resonance frequency at wave vector M. Subsequently, physical information is embedded into a forward prediction neural network, yielding a pre-trained model capable of accurately predicting the metamaterial's dispersion curves. Finally, a loss function combining the pre-trained model and geometric constraints is employed to train an inverse design model. Results show that the bandgap range of the inverse-designed metamaterial deviates from the target value by no more than 3.5%, validating the reliability of the proposed method. In summary, this work overcomes the limitations of conventional topology-based metamaterial inverse design and provides a novel approach for active bandgap control in vibration control applications.
  • DONG Yiqing, CAO Han, YAO Lei, DONG Changrong, FAN Xinyu, REN Jiannan, ZHI Jie, YANG Weidong, LI Yan
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    Fiber-reinforced composites are widely used in aerospace industries. Their manufacturing quality is directly influenced by the curing process. However, modeling of the curing process faces the challenge of balancing computational accuracy and efficiency. Finite element analysis using low-order solid elements with coarse meshes often suffers from shear locking. To this end, this paper proposes an efficient sequentially coupled multiphysics method based on solid-shell elements. It integrates models of heat transfer, curing kinetics, and mechanical analysis. In the deformation analysis, solid-shell elements are introduced, combined with the enhanced assumed strain (EAS) and assumed natural strain (ANS) methods to effectively suppress shear locking. A sequentially coupled computational procedure is implemented using Abaqus. The proposed method is demonstrated through three typical cases, including an antisymmetric laminated plate, a C-section component, and a T-stiffened panel. The results indicate that the sequentially coupled analysis model based on solid-shell elements significantly improves both the accuracy and computational efficiency of curing deformation prediction, offering a reliable and efficient solution for composite manufacturing optimization.
  • TIAN Yuxin, LIU Qingquan, WANG Xiaoliang
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    The interaction between dense granular flows and structures is widely encountered in geological hazard mitigation and protective structure design, such as the impact of major disasters along the Sichuan-Tibet Railway on bridge piers. Therefore, a deep understanding of the flow characteristics and regularities of granular flows interacting with structures is of great significance for structural design and disaster prevention and reduction. Based on the Hertz-Mindlin contact theory, this paper establishes a discrete element model suitable for studying the interaction between dense granular flows in a chute and a cylindrical obstacle. Firstly, by analyzing the spatiotemporal evolution of flow thickness and average velocity, the influences of chute inclination angle and particle friction coefficient are systematically investigated, and a scheme for preparing a stable incoming flow is proposed accordingly. Further research on the evolution of the flow structure under the action of the obstacle reveals that in the supercritical flow regime (Fr > 1), a bow shock forms upstream of the cylindrical obstacle after impact, whose dimensionless height is positively correlated with the Fr number, consistent with the trend predicted by shock wave theory. Downstream, a particle vacuum zone forms, whose morphology changes regularly with the Fr number: when Fr > 4, the vacuum zone exhibits an open structure; when 1 < Fr < 4, it shows a closed structure, and its degree of closure increases as the Fr number decreases. In the subcritical regime (Fr < 1), no distinct shock wave or vacuum zone structures are observed. This study clarifies the quantitative influence of the Fr number on the flow structure around the obstacle, laying a foundation for a deeper understanding of the interaction mechanism between granular flows and structures and the theoretical modeling of impact loads, and provides effective references for engineering protection design in disaster-prone areas.    
  • ZOU Minqi, CANG Yu
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    This work systematically investigates the tunability of phononic band structures in binary disordered colloidal glasses by jointly varying the particle relative volume fraction (φ), size ratio (R), and compositional ratio. Combining Brillouin light scattering measurements with scanning electron microscopy characterization, a continuous structural evolution from nearly ordered to highly disordered states is established. Under weak size disparity conditions (R = 1.17), the particle relative volume fraction (φ) is identified as the primary parameter governing the degree of disorder and the resulting phonon dispersion. With increasing disorder, the Bragg bandgap progressively closes, whereas the hybridization bandgap—originating from the anti-crossing between localized vibrational modes and propagating acoustic modes—persists and exhibits remarkable robustness. Upon increasing the size disparity (R = 1.38~2.24), a coupled effect of particle size contrast and compositional ratio on spatial correlations emerges. At intermediate relative volume fractions, where the structure is highly disordered, only the hybridization gap remains. In contrast, at low relative volume fractions with equimolar composition, sufficient spatial correlations can still develop despite the overall disorder, leading to the reappearance of Bragg scattering and the formation of dual bandgaps. These results demonstrate that the Bragg bandgap is highly sensitive to long-range order or effective spatial correlations, whereas the hybridization bandgap is governed by local resonance mechanisms and remains inherently robust against disorder. Overall, this study elucidates the interplay between structural disorder and phononic bandgap formation in colloidal systems, providing fundamental insights and practical guidelines for designing disordered phononic materials with tunable acoustic functionalities.
  • WANG Dongdong, YU Yin, WANG Qizheng, TU Changqing
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    Failure test and post-buckling analysis methods of composite stiffened panel were studied for its stability and load-carrying capacity under shear loading considering low-velocity impact damage. Digital image correlation (DIC) was employed to capture the full deformation process of the specimens in real time. A finite element model was established using the 2D-Hashin criterion and the quadratic nominal stress criterion to characterize the failure of composite materials and adhesive interfaces,respectively. In addition,a softening inclusion approach combined with Python was adopted to identify the equivalent impact-damaged region based on element coordinates and degrade initial stiffness,thereby avoiding geometric partitioning and preserving mesh quality. Comparison with experimental results shows that low-velocity impact damage affects the local stiffness distribution of the structure,thereby breaking the symmetry of the buckling mode. The finite element analysis method established in this study demonstrates good correlation with experimental results in predicting buckling/failure loads and failure modes.
  • GU Hao, DOU Yibin, ZHAO Jian
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    As a critical component for attitude control and maneuvering flight of high-speed flight vehicles, the rudder is subjected to severe aerodynamic heating and reactive gas erosion during service, which readily induces surface ablation recession and consequent variations in structural response, thereby posing significant challenges to rudder structural design. This paper presents a numerical analysis framework coupling transient thermochemical ablation with heat transfer for carbon/carbon (C/C) composite rudder structures. A finite-rate ablation model is adopted, incorporating a transient update algorithm for ablation heat flux and dynamic mesh techniques, enabling coupled simulation of the transient evolution of the ablative surface and the thermo-mechanical response. Using three typical rudder configurations, the study systematically examines the evolution of ablation morphology, mass loss, temperature field, and mechanical response under thermal loading, thereby validating the feasibility of the proposed method. The findings are expected to provide methodological guidance and practical references for ablation performance assessment and structural design of thermal protection systems in high-speed flight vehicles.
  • YI Wanshuang, YANG Sifan, LI Yongbo, LIU Ke, ZHANG Zhi, WANG Bofu
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    This study addresses the difficulty of identifying unsteady turbulent structures in the vaneless region of a large Francis turbine under wide-load operation. Large eddy simulation (LES) based on the Wall-Adapting Local Eddy-viscosity (WALE) subgrid-scale model, combined with proper orthogonal decomposition (POD), was used to analyze the flow-field topology, POD energy distribution, and evolution of dominant modes under 200 MW, 400 MW, and 840 MW operating conditions. The results show that, under low-load conditions, flow separation at the trailing edge of the guide vanes and large-scale vortex shedding are pronounced, leading to a more dispersed distribution of turbulent kinetic energy. As the load increases, the high-speed jet compresses and dissipates the trailing-edge shedding vortices, increasing the energy concentration of the low-order modes. The dominant flow pattern gradually shifts from a rotating mode to a wake mode. These findings provide a modal-analysis basis for identifying flow instability in the vaneless region of wide-load turbines and for assessing operational stability.
  • DUAN Yuyang, WANG Shiyou, CHEN Hao, CHEN Jiping, YANG Weidong
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    The Vacuum Assisted Resin Transfer Molding (VARTM) process for composites is prone to dry spot defects due to insufficient local resin infiltration, which significantly compromises the mechanical performance. This paper investigates the influence of dry spot defects on the mechanical properties and failure modes of composites. Laminates with prefabricated dry spots of varying sizes and spacings were manufactured via the VARTM process, followed by non-destructive testing and mechanical property characterization. Finite element simulation based on the Hashin failure criterion and an energy-based damage evolution model was employed to correlate defect parameters with structural performance. The results indicate that dry spots significantly reduce the compressive and interlaminar shear strength of composites, with larger defects leading to more pronounced degradation. A multi-spot layout (Φ10 mm dry spot with spacing 16 mm) enhances the initial damage and failure loads compared to a single-spot configuration. Under three-point bending, structural failure initiates with matrix compressive damage on the upper surface, ultimately leading to global failure. Conversely, the tensile and flexural strength of the composites show insensitivity to the presence of dry spot defects. This study provides theoretical and experimental support for the performance evaluation and process optimization of VARTM composites containing defects.
  • ZHANG Peng, ZHANG Yongran, TANG Jingqi, TANG Keke
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    Phase-field fracture models can describe complex crack evolution without explicitly tracking crack surfaces, but the fine-mesh requirement induced by small length scales, the nonlinear coupling between the displacement and phase fields, and incremental-iterative solution procedures lead to high computational costs. To alleviate these bottlenecks, deep learning has been progressively introduced into full-field response prediction, local subproblem solution, and parametric model construction, providing multiple routes for accelerating and reformulating phase-field fracture computation. After outlining the variational basis and numerical solution procedure of phase-field fracture, this paper classifies existing methods into four categories according to where neural networks intervene in the computational workflow and which components they primarily replace: fully data-driven surrogate models, finite element-neural network hybrid solvers, physics-driven neural solvers, and neural operators. Drawing on representative studies, public benchmarks, and computational implementations, these methods are compared in terms of data and physical constraints, offline investment and online benefits, generalization, and engineering reliability. The analysis indicates that deep learning does not uniformly replace conventional numerical methods but reallocates the costs of data generation, model training, physical modeling, and online solution for different tasks; the applicability of a specific method therefore depends on data conditions,query scale, and reliability requirements.Future research should advance standardized benchmarks, unified full-cost evaluation, and reliability validation based on key mechanical quantities, while promoting the integration of neural networks with conventional numerical methods to progressively establish a comparable, verifiable, reproducible, and engineering-oriented intelligent fracture computation framework.
  • ZHANG Zhiyi
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    Physics-based crystal plasticity constitutive models involve numerous history-dependent plastic variables, which frequently trigger convergence instabilities when employed with adaptive mesh refinement algorithms designed to enhance computational efficiency. Conventional component-wise interpolation of the plastic deformation gradient compromises reversibility, destroys the orthogonality of the rotational component, and violates the plastic incompressibility constraint due to volumetric expansion effects. To address this challenge, this paper established a multi-field coupled crystal plasticity-phase-field fracture finite element model within a finite-deformation and thermodynamically consistent framework. Furthermore, a structure-preserving plastic state transfer algorithm categorized based on mathematical manifolds was proposed. This algorithm decomposed the plastic deformation gradient into plastic rotation and the plastic right Cauchy-Green tensor, applying rotational projection regression and Log-Euclidean mapping respectively; it was complemented by cross-variable consistency correction at the plastic front and mechanical re-equilibration to ensure robust computation. A single-notch shear benchmark problem validated the coupled algorithm, and simulations of cracking in polycrystalline stainless steel under multi-field loading demonstrated crack distributions and propagation patterns consistent with experimental observations. The results indicated that the proposed algorithm maintained robust state transfer under conditions of large-deformation plastic history, providing a reliable tool for the adaptive finite element simulation of complex multi-physics fracture problems.
  • LIU Yinglong, QIAN Shenghui, XI Wei, CUI Pengfei
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    Numerical simulation of compression after impact (CAI) usually requires continuous modeling of low-velocity impact, post-impact vibration decay, and subsequent compression, which leads to high computational cost and limits its application in large-scale layup parametric studies. Stepwise analysis can improve computational efficiency, but its key challenge lies in accurately transferring the impact-induced damage state to the compression model. To address this issue, this study proposes a damage-variable transfer method for stepwise CAI analysis. At the end of the low-velocity impact analysis, the fiber tensile damage, fiber compressive damage, matrix tensile damage, and matrix compressive damage variables of each element are extracted to calculate residual stiffness factors, and the irreversible impact damage state is transferred to the subsequent compression model by updating material properties. The method transfers only the damage state directly related to stiffness degradation and load-bearing capacity reduction, instead of transferring the post-impact velocity, displacement, and transient stress states, thereby decoupling the impact and compression analyses. Based on this method, T700GC/M21 composite Double-Double (DD) laminates are investigated. A total of 100 [±Φ/±Ψ] layup configurations are constructed, and low-velocity impact, compression after impact, and compression before impact simulations are conducted for each configuration. The results show that layup angle combinations significantly influence impact damage distribution, CAI strength, and strength retention by changing laminate stiffness characteristics, load diffusion paths, and damage evolution processes. The proposed method and parametric results provide a reference for DD laminate layup design and impact damage tolerance assessment.
  • HUANG Yunfei, ZHU Huixin, FU Kunkun, CUI Xiaoyu, YUAN Bin
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    This paper studied the lightning attachment problem of aero-engine fan blades. Based on the theory of Magnetohydrodynamics (MHD), a numerical model was developed that coupled several fields to simulate the formation and attachment of lightning channels to blades: electromagnetics, heat, and fluid flow. An artificial lightning attachment experimental platform was designed and constructed, and lightning attachment tests were conducted at various blade rotation angles. The development of lightning leaders and attachment locations were recorded. The results showed that lightning attachment generally occurred near the tip of the blade closest to the discharge electrode, and the tip discharge effect was the main cause of this final attachment location. The attachment positions and lightning channel shapes predicted by the model were in good agreement with the experimental results, validating the proposed model. Using the validated model, the influence of key parameters such as current density, temperature and Lorentz force on lightning attachment was explored to uncover multi-field coupling characteristics in the lightning attachment process.
  • LÜ Xilin, LIU Kai, LIANG Hanwen, ZENG Sheng, MA Yiyue, LIU Xianlin
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    When coarse-grained subgrade materials contain soft rock particles, these particles are prone to breakage during shearing, resulting in changes in their mechanical behavior and affecting the engineering performance of the subgrade. Based on the large-scale triaxial consolidated drained shear test and theoretical analysis, the relationship between the static characteristics of medium dense and dense coarse-grained materials containing soft rock and the initial relative density and confining pressure is studied, and the influence of soft rock particle breakage on the strength and dilatancy characteristics is analyzed. The results show that the dense and medium dense coarse-grained materials containing soft rock show the characteristics of strain hardening and continuous shear shrinkage, only show strain softening and slight shear dilatancy under high compactness and low confining pressure condition, which reflects the influence of soft rock particle breakage on the constitutive characteristics in the shear process. The particle breakage rate increases nonlinearly with the relative compactness and confining pressure of the sample, and the compactness has more obvious effect on particle breakage. The particle breakage of coarse-grained materials containing soft rock mainly occurs in the shear shrinkage stage, and the particle breakage of soft rock inhibits and compensates the potential dilatancy of the sample, resulting in that the dilatancy of coarse-grained materials containing soft rock is not sensitive to the compactness and confining pressure.
  • XU Yuce, ZHOU Xiaoli, WEI Peijun, LI Li
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    To deeply reveal the creep behavior of open cylindrical shells under long-term loads, this paper constructs a fractional-order Pasternak viscoelastic foundation model based on fractional calculus theory, which can more accurately describe the rheological properties of the foundation. The differences in creep response between open cylindrical shells on fractional-order and integer-order viscoelastic foundations were systematically studied. Firstly, the Riemann-Liouville fractional derivative definition was introduced, and the expression of Pasternak foundation reaction considering the viscoelasticity of the compression layer and the elasticity of the shear layer was derived. Combining Laplace transform and inverse transform with the properties of Mittag-Leffler function, the creep displacement solution was obtained. The influence of fractional order coefficient, viscous coefficient, and shear elastic modulus on the creep process was systematically explored. By comparing with existing literature, the reliability of the numerical results presented in this paper was validated. The results show that the fractional-order model can more accurately reflect the initial elastic response and long-term creep attenuation characteristics of the foundation. Increasing the viscous coefficient or shear elastic modulus can suppress creep deformation, while increasing the fractional order will enhance long-term creep development. The model integrating the fractional-order Pasternak foundation and the cylindrical shell provides a theoretical basis for the long-term performance evaluation and parameter optimization of shell structures considering soil rheological effects in practical engineering.
  • CHEN Anquan, LIN Hangwei
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    The analytical expression for buckling analysis of beams serves as a benchmark for validating the accuracy of numerical methods and accurate analytical formulations for predicting buckling loads are essential. This study models the beam buckling process as an incremental transition from the C1 configuration to the C2 configuration. Based on the incremental theory of nonlinear deformation analysis of deformable bodies, the incremental virtual work equilibrium equation for planar beams is derived. Furthermore, by incorporating the static and kinematic relationships at the beam cross-section and employing the definition of Green–Lagrange strain, both a complete incremental theory and a simplified incremental theory are established. The complete theory accounts for higher-order terms in axial nonlinear strain, whereas the simplified version neglects these terms. Subsequently, the corresponding buckling differential equations and boundary conditions are formulated for both theories. Results indicate that the buckling differential equation derived from the complete incremental theory includes additional terms associated with higher-order axial nonlinear strain components, which are omitted in classical stability theory. In contrast, the differential equation based on the simplified incremental theory aligns exactly with the classical formulation. Finally, through buckling analyses of planar beams under various support conditions, closed-form analytical expressions for buckling loads are obtained for both theories. The expression derived from the simplified incremental theory coincides with the classical solution, while that from the complete incremental theory incorporates correction terms arising from higher-order axial strain effects, thereby providing a more generalized analytical expression for the buckling load of planar compression members. The derivation and application framework of these two incremental theories can be extended to analytical studies on three-dimensional beam torsion and out-of-plane instability phenomena.
  • TAN Weizi
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    Siltation in the foundation trench of immersed tunnels is a critical issue affecting engineering safety and operational costs. However, the influence of water temperature changes on sediment fluidity has not been fully incorporated into existing siltation prediction models. To address the limitation of current models’ applicability in temperature-sensitive regions, a novel temperature-dependent rheological constitutive model is proposed. This model integrates the Power-law model, Herschel-Bulkley model, and Arrhenius equation, enabling the characterization of both shear-thickening and shear-thinning behaviors of sediment slurry. Utilizing locally measured data from the Yellow River, Lianyungang, and the Yangtze River Estuary to deduce parameters and conduct verification, the model achieves prediction errors of less than 10% within the temperature range of 0~35 ℃. When applied to simulating siltation in the foundation trench of the Yuzhu immersed tunnel in the Pearl River under 3~40 ℃ conditions, the predicted siltation depth (0.48 m at 40 ℃) showed good agreement with on-site multibeam bathymetric survey results (0.4~0.5 m). This model provides a reliable theoretical tool and engineering application basis for predicting siltation in immersed tunnel foundation trenches within temperature-sensitive regions.
  • DONG Xinlei, ZHOU Xiaoli, WEI Peijun, LI Li
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    This paper studies the free vibration problem of functionally graded Timoshenko beams on fractional-order Pasternak viscoelastic foundations. By introducing a fractional-order viscoelastic foundation model, we establish the free vibration equation for functionally graded Timoshenko beams on such a foundation. Using the differential-integral quadrature method(DIQM), we numerically calculate the beam's complex natural frequencies and vibrational modes, and compare them with analytical methods and literature results to validate our approach. Parametric analysis reveals how the functionally graded index, the fractional-order coefficient of the viscoelastic foundation, and the viscous coefficient affect the natural frequencies and damping factors of functionally graded Timoshenko beams.
  • LIN Guiping, PENG Yiming, GUO Yawen, YIN Yunting, ZHU Yilin
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    Tubular auxetic structures with negative Poisson's ratio have attracted increasing attention in energy absorption, deformation compatibility, and structural protection fields, where their equivalent elastic properties are strongly governed by the underlying microstructural topology. In this work, a novel tubular enhanced anti-tetra missing-rib chiral auxetic structure is proposed by extending the planar enhanced anti-tetra missing-rib geometry into a tubular configuration. Based on the energy method combined with Castigliano's theorem, analytical expressions for the equivalent axial elastic modulus and Poisson's ratio of the tubular structure under axial loading are derived. The intrinsic relationships between geometric parameters and equivalent elastic properties are established, and the influence of key microstructural parameters on the mechanical response is systematically investigated. The results indicate that the proposed structure exhibits a widely tunable negative Poisson's ratio and effective stiffness through rational geometric design. Finite element simulations are performed to validate the theoretical predictions, showing good agreement with the analytical solutions. The present study provides a theoretical basis for the mechanical design and potential engineering applications of tubular auxetic structures.
  • ZHANG Junhua, WU Minjun, MIAO Yi, ZHOU Zhiguang
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    The adjacent structure, comprising a primary structure and a subsidiary structure, has attracted considerable attention in modern society due to its functional diversity and flexibility in spatial layout. However, the dynamic characteristics of the substructures within adjacent structures are inherently inconsistent, and the resulted structural irregularity renders them more susceptible to damage under seismic excitation. To enhance the seismic performance of high-rise adjacent structures and ensure their safety and serviceability during earthquakes, this study employs a triple friction pendulum bearing, which exhibits multi-stage stiffness, self-centering capability, frictional energy dissipation, and adaptability to multi-level seismic actions, in combination with a nonlinear viscous damper for isolation control. First, the device configuration, mechanical principles, and application advantages of the proposed isolation system are elucidated. Subsequently, the triple friction pendulum bearing isolation system is designed for a practical high-rise adjacent structure, and its isolation efficiency is evaluated through nonlinear time-history analyses under design-basis, maximum-considered, and extremely rare earthquakes. Finally, the applicability of the proposed system is further investigated under varying site conditions. The results indicate that the proposed triple friction pendulum bearing isolation system significantly reduces the seismic responses of the high-rise adjacent structure, and alleviates the acceleration abruptness and whiplash effect in the primary structure of the adjacent system. Moreover, the triple friction pendulum bearing exhibits distinct equivalent stiffnesses under different seismic intensity levels, confirming its self-adaptive characteristics. The proposed isolation system demonstrates satisfactory control effectiveness under both stiff-soil and soft-soil site conditions. This study is expected to provide a reference for the application of triple friction pendulum bearings in high-rise adjacent structures.
  • RAO Yin, LI Yong, GUO Yunpeng, WU Yunhao, ZHANG Kai
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    The Silicon-based anodes in lithium-ion batteries undergo significant volume changes during lithiation and delithiation, which can generate diffusion-induced stress, cause mechanical damage, and eventually lead to capacity fading and structural instability. During lithiation, crystalline silicon exhibits pronounced crystallographic anisotropy in lithium transport, which results in non-uniform expansion and stress concentration and may further trigger particle cracking. In this study, a two-dimensional chemo-mechanical finite element model is established for silicon particles by considering diffusion coefficient anisotropy, orthotropic elasticity, and anisotropic chemical expansion. By comparing isotropic and anisotropic cases and further incorporating particle shape and size, the effects of geometry and anisotropy on the chemo-mechanical response of silicon-based particles are systematically investigated. The results show that diffusion coefficient anisotropy is the dominant factor governing the non-uniform evolution of the coupled fields. It enhances the inhomogeneity of lithium concentration and amplifies the concentration gradient, thereby leading to more severe stress concentration. A comparison among different particle shapes further indicates that circular particles exhibit a larger stress amplification factor under anisotropic conditions than non-circular particles. This suggests that appropriately designed non-circular geometries can partially mitigate the stress amplification induced by anisotropy through geometric constraint. The present study provides useful guidance for the structural stability design of silicon-based electrodes.