Underground engineering in extreme environments necessitates understanding rock mechanical behavior under coupled high-temperature and dynamic loading conditions.This study presents an innovative multi-scale cross-pla...Underground engineering in extreme environments necessitates understanding rock mechanical behavior under coupled high-temperature and dynamic loading conditions.This study presents an innovative multi-scale cross-platform PFC-FDEM coupling methodology that bridges microscopic thermal damage mechanisms with macroscopic dynamic fracture responses.The breakthrough coupling framework introduces:(1)bidirectional information transfer protocols enabling seamless integration between PFC’s particle-scale thermal damage characterization and FDEM’s continuum-scale fracture propagation,(2)multi-physics mapping algorithms that preserve crack network geometric invariants during scale transitions,and(3)cross-platform cohesive zone implementations for accurate SHTB dynamic loading simulation.The coupled approach reveals distinct three-stage crack evolution characteristics with temperature-dependent density following an exponential model.High-temperature exposure significantly reduces dynamic strength ratio(60%at 800℃)and diminishes strain-rate sensitivity,with dynamic increase factor decreasing from 1.0 to 2.2(25℃)to 1.0-1.3(800℃).Critically,the coupling methodology captures fundamental energy redistribution mechanisms:thermal crack networks alter elastic energy proportion from 75%to 35%while increasing fracture energy from 5%to 30%.Numerical predictions demonstrate excellent experimental agreement(±8%peak stress-strain errors),validating the PFC-FDEM coupling accuracy.This integrated framework provides essential computational tools for predicting complex thermal-mechanical rock behavior in underground engineering applications.展开更多
Developing sensorless techniques for estimating battery expansion is essential for effective mechanical state monitoring,improving the accuracy of digital twin simulation and abnormality detection.Therefore,this paper...Developing sensorless techniques for estimating battery expansion is essential for effective mechanical state monitoring,improving the accuracy of digital twin simulation and abnormality detection.Therefore,this paper presents a data-driven approach to expansion estimation using electromechanical coupled models with machine learning.The proposed method integrates reduced-order impedance models with data-driven mechanical models,coupling the electrochemical and mechanical states through the state of charge(SOC)and mechanical pressure within a state estimation framework.The coupling relationship was established through experimental insights into pressure-related impedance parameters and the nonlinear mechanical behavior with SOC and pressure.The data-driven model was interpreted by introducing a novel swelling coefficient defined by component stiffnesses to capture the nonlinear mechanical behavior across various mechanical constraints.Sensitivity analysis of the impedance model shows that updating model parameters with pressure can reduce the mean absolute error of simulated voltage by 20 mV and SOC estimation error by 2%.The results demonstrate the model's estimation capabilities,achieving a root mean square error of less than 1 kPa when the maximum expansion force is from 30 kPa to 120 kPa,outperforming calibrated stiffness models and other machine learning techniques.The model's robustness and generalizability are further supported by its effective handling of SOC estimation and pressure measurement errors.This work highlights the importance of the proposed framework in enhancing state estimation and fault diagnosis for lithium-ion batteries.展开更多
Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and capro...Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and caprock under in-situ high-temperature and confine-ment conditions is of considerable importance. Compared to conventional mechanical experiments on rock samples after high-temperat-ure treatment, in-situ high-temperature experiments can more accurately characterize the behavior of rocks in practical engineering,thereby providing a more realistic reflection of their mechanical properties. In this study, an in-situ high-temperature triaxial compressiontesting machine is developed to conduct in-situ compression tests on sandstone at different temperatures(25, 200, 400, 500, and 650℃)and confining pressures(0, 10, and 20 MPa). Based on the experimental results, the temperature-dependent changes in compressivestrength, peak strain, elastic modulus, Poisson's ratio, cohesion, and internal friction angle are thoroughly analyzed and discussed. Resultsindicate that the mass of sandstone gradually decreases as the temperature increases. The thermal conductivity and thermal diffusivity ofsandstone exhibit a linear relationship with temperature. Peak stress decreases as the temperature rises, while it increases with higher con-fining pressures. Notably, the influence of confining pressure on peak stress diminishes at higher temperatures. Additionally, as the tem-perature rises, the Poisson's ratio of sandstone decreases. The internal friction angle also decreases with increasing temperature, with 400℃ acting as the threshold temperature. Interestingly, under uniaxial conditions, the damage stress of sandstone is less affected by tem-perature. However, when the confining pressure is 10 or 20 MPa, the damage stress decreases as the temperature increases. This study en-hances our understanding of the influence of in-situ high-temperature and confinement conditions on the mechanical properties of sand-stone strata. The study also provides valuable references and experimental data that support the development of low-to medium-maturityoil shale resources.展开更多
The reaction of Mg^(2+)and 5-{1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl}terephthalic acid(H_(2)L)leads to two metal-organic frameworks,[Mg(L)(DMF)_(2)(H_(2)O)_(2)]_(2)·5DMF·2H_(2)O(1)with a 1D structure and...The reaction of Mg^(2+)and 5-{1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl}terephthalic acid(H_(2)L)leads to two metal-organic frameworks,[Mg(L)(DMF)_(2)(H_(2)O)_(2)]_(2)·5DMF·2H_(2)O(1)with a 1D structure and[Mg_(2)(L)_(2)(DMSO)_(3)(H_(2)O)](2)with a 2D(4,4)-net structure.Interestingly,the two compounds exhibit distinct luminescent responses to external mechanical stimuli.1 exhibited exceptional resistance mechanical chromic luminescence(RMCL),which can be attributed to the predominant hydrogen bonds and the presence of high-boiling-point solvent molecules within its structure.2 had a reversible MCL property,which can be attributed to the dominantπ-πweak interactions,coupled with the reversible destruction/restoration of its crystallinity under grinding/fumigation.CCDC:2410963,1;2410964,2.展开更多
The accepted doping ion in Ti^(4+)-site of PbZr_(y)Ti_(1–y)O_(3)(PZT)-based piezoelectric ceramics is a well-known method to increase mechanical quality factor(Q_(m)),since the acceptor coupled by oxygen vacancy beco...The accepted doping ion in Ti^(4+)-site of PbZr_(y)Ti_(1–y)O_(3)(PZT)-based piezoelectric ceramics is a well-known method to increase mechanical quality factor(Q_(m)),since the acceptor coupled by oxygen vacancy becomes defect dipole,which prevents the domain rotation.In this field,a serious problem is that generally,Qm decreases as the temperature(T)increases,since the oxygen vacancies are decoupled from the defect dipoles.In this work,Q_(m) of Pb_(0.95)Sr_(0.05)(Zr_(0.53)Ti_(0.47))O_(3)(PSZT)ceramics doped by 0.40%Fe_(2)O_(3)(in mole)abnormally increases as T increases,of which the Qm and piezoelectric coefficient(d_(33))at room temperature and Curie temperature(TC)are 507,292 pC/N,and 345℃,respectively.The maximum Qm of 824 was achieved in the range of 120–160℃,which is 62.52%higher than that at room temperature,while the dynamic piezoelectric constant(d_(31))was just slightly decreased by 3.85%.X-ray diffraction(XRD)and piezoresponse force microscopy results show that the interplanar spacing and the fine domains form as temperature increases,and the thermally stimulated depolarization current shows that the defect dipoles are stable even the temperature up to 240℃.It can be deduced that the aggregation of oxygen vacancies near the fine domains and defect dipole can be stable up to 240℃,which pins domain rotation,resulting in the enhanced Q_(m) with the increasing temperature.These results give a potential path to design high Q_(m) at high temperature.展开更多
Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological beh...Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological behavior of GNP/epoxy nanocomposites.This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance.A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites.Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix.The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite.The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step,producing well-dispersed nanocomposites with improved mechanical properties.Particularly,the nanocomposites at a low GNP loading of 0.1 wt%,demonstrate superior mechanical strength,as shown by increased tensile properties,including improved Young's modulus(1.86 GPa),strength(57.31 MPa),and elongation at break(4.98).The nanocomposite with 0.25 wt%GNP loading performs better,according to the viscoelastic analysis and flexural properties(113.18 MPa).Except for the nanocomposite with a 0.5 wt%GNP loading,which has a higher thermal breakdown temperature,the thermal characteristics do not significantly alter.The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization.The findings help with filler selection and identifying the best dispersion approach,which improves mechanical performance.The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites.In fields like aerospace,automotive,and electronics where higher mechanical performance and functionality are required,GNPs'improved mechanical properties and successful dispersion present exciting potential.展开更多
Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite.The micromechanical behavior...Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite.The micromechanical behavior of Yanshanian granite is investigated using scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)and nanoindentation tests.The results demonstrate transitional mechanical properties at mineral interfaces.The elastic modulus and hardness exhibit intermediate values between adjacent mineral phases.The higher plasticity indices at the interfaces suggest higher plastic deformation capacity of hard-phase minerals in these regions.Additionally,fracture toughness measurements of minerals and interfaces were obtained,with interfacial values ranging from 0.90 to 1.63 MPa·m^(0.5).The analysis of mechanical property relationships shows a significant positive linear correlation between rock-scale elastic modulus and fracture toughness.However,this correlation is substantially lower at the mineral scale,demonstrating a scale effect in the relationship of different mechanical properties.展开更多
With the economic and social development of the country,vocational education is playing an increasingly significant role in cultivating highly skilled talents.However,the mechanical drawing courses in vocational colle...With the economic and social development of the country,vocational education is playing an increasingly significant role in cultivating highly skilled talents.However,the mechanical drawing courses in vocational colleges still face numerous challenges in the teaching process,such as outdated textbook content,inadequate practical resources,weak teaching staff,and low student interest.This paper aims to explore these issues and propose corresponding coping strategies.The findings of this study not only provide specific improvement suggestions for vocational colleges but also emphasize the importance of these strategies in enhancing students’comprehensive abilities and promoting the development of vocational education.By addressing these challenges,this paper contributes to the enhancement of teaching quality and the overall advancement of vocational skills education.展开更多
The unbreakable doll performance at Tang Dynasty Night City has become extremely popular,sparking a wave of enthusiasm online.In the performance,actors dressed in elegant Tang Dynasty attire appear as if they have ste...The unbreakable doll performance at Tang Dynasty Night City has become extremely popular,sparking a wave of enthusiasm online.In the performance,actors dressed in elegant Tang Dynasty attire appear as if they have stepped out of a historical painting,gracefully dancing on the unbreakable doll apparatus.Every gesture and expression exudes the unparalleled elegance of the Tang Dynasty.This paper primarily analyzes the mechanical principles behind the Tang Dynasty Night City’s Unbreakable Doll Performance,starting with structural design to examine its mechanical principles and summarize its dynamic mechanical control mechanisms.展开更多
Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have ga...Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have garnered increasing research interest.However,most metallic lattice structures generally exhibit anisotropic characteristics,which limits their application ranges.Additionally,a limited number of studies have successfully developed precise mechanical models,which have undergone experimental validation,for the purpose of describing the mechanical response exhibited by additively manufactured metallic lattice structures.In this study,Kelvin lattice structures with varying porosities were systematically designed and fabricated using laser powder bed fusion(LPBF)technology.By integrating finite element simulations with experimental characterization,an enhanced mechanical model was developed through a modification of the Gibson-Ashby model,providing an accurate quantitative description of the relationship between porosity and mechanical properties.The results show that the revised mechanical model can accurately describe the relationship between the geometric parameters and properties of metallic lattice structures.Specifically,the designed Kelvin lattice structures exhibit a smooth stress-strain curve with an obvious yield platform,demonstrating isotropic mechanical properties in all the three spatial directions.This enhances their suitability for complex loading conditions.Meanwhile,the microstructure and manufacturing accuracy of the Kelvin lattice structures were observed and analyzed by micro computed tomography.The results show that the fabricated metallic lattice structures achieved precise dimensional control and optimal densification.This study presents the complete process involved in modeling the Kelvin structure,including its conceptualization,manufacturing,implementation,and ultimately,disposal.展开更多
Multi⁃field coupling problems involving species transport,heat transfer,substance transformation,and mechanical deformation are prevalent in various scenarios,such as the curing of early⁃age concretes,the response of ...Multi⁃field coupling problems involving species transport,heat transfer,substance transformation,and mechanical deformation are prevalent in various scenarios,such as the curing of early⁃age concretes,the response of soft materials,the oxidation of metals,the lithiation and delithiation of lithium⁃ion batteries,and the self⁃healing of biological tissues.Thermo⁃chemo⁃mechanical coupling dynamics are common characteristics of these problems,making theoretical studies on such processes of significant importance.This study offers a thorough review of advanced theoretical models that address thermo⁃chemo⁃mechanical behavior of solid materials within the theoretical framework of non⁃equilibrium thermodynamics.First,we outline the thermo⁃chemo⁃mechanical coupling phenomena observed in various application scenarios.Then,the theoretical developments of classical continuum mechanics include the phase field method and peridynamics in the contexts of thermo⁃mechanical coupling,chemo⁃mechanical coupling,and thermo⁃chemo⁃mechanical coupling,respectively.Finally,challenges faced by thermo⁃chemo⁃mechanical coupling research are highlighted and prospects and directions for this field are also outlined.This paper helps to understand the history and trends in the development of thermo⁃chemo⁃mechanical coupling theory.展开更多
On May 9,2025 on the campus of the University of Science and Technology of China(USTC),Chinese Academy of Sciences(CAS),an exhibition was unveiled to celebrate the UN International Year of Quantum Science and Technolo...On May 9,2025 on the campus of the University of Science and Technology of China(USTC),Chinese Academy of Sciences(CAS),an exhibition was unveiled to celebrate the UN International Year of Quantum Science and Technology(IYQ)-a one-year-long worldwide event in memory of the founding of quantum mechanics(QM).展开更多
Microstructural heterogeneity of low-permeability sandstone roofs of deep unmineable coal seams due to diagenesis significantly affects rock mechanical behavior,greatly impacting the sealing potential of in situ CO_(2...Microstructural heterogeneity of low-permeability sandstone roofs of deep unmineable coal seams due to diagenesis significantly affects rock mechanical behavior,greatly impacting the sealing potential of in situ CO_(2) sequestration and the structural stability of the geological formation.However,little is known about how the microstructure of different mineral groups influences the multiscale mechanical behavior of deep sandstone.This study proposes a new method for quantitatively characterizing the multiscale mechanical properties of low-permeability sandstone and shows the mechanisms responsible for mechanical failure at the micro-,meso-,and macroscale.Triaxial compression tests and targeted nanoindentation tests were conducted to assess the micro-and macroscale mechanical properties of different types of sandstone.The micro-and macroscale experiments were coupled with numerical simulations of compression using a unified cohesive model based on Voronoi polygons to clarify the multiscale mechanical behavior.The results indicate that quartz,the primary mineral component of the sandstones examined,exhibits the strongest micromechanical properties,followed by feldspar,calcite,and clay minerals.Compared to polycrystalline quartz,monocrystalline quartz has a more stable microstructure and is mechanically stronger.The macro-mechanical properties of tight sandstone samples are weakened by increased microstructural inhomogeneity and larger grain size.This leads to a higher likelihood of splitting damage,characterized by a high degree of discrete and weak stress sensitivity.The major conclusion is that the positive rhythm lithofacies of medium-grained sandstone to siltstone are the most favorable for efficient CO_(2) sequestration in deep unmineable coal seams.展开更多
1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain bounda...1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].展开更多
The integration of physics-based modelling and data-driven artificial intelligence(AI)has emerged as a transformative paradigm in computational mechanics.This perspective reviews the development and current status of ...The integration of physics-based modelling and data-driven artificial intelligence(AI)has emerged as a transformative paradigm in computational mechanics.This perspective reviews the development and current status of AI-empowered frameworks,including data-driven methods,physics-informed neural networks,and neural operators.While these approaches have demonstrated significant promise,challenges remain in terms of robustness,generalisation,and computational efficiency.We delineate four promising research directions:(1)Modular neural architectures inspired by traditional computational mechanics,(2)physics informed neural operators for resolution-invariant operator learning,(3)intelligent frameworks for multiphysics and multiscale biomechanics problems,and(4)structural optimisation strategies based on physics constraints and reinforcement learning.These directions represent a shift toward foundational frameworks that combine the strengths of physics and data,opening new avenues for the modelling,simulation,and optimisation of complex physical systems.展开更多
This paper presents a novel element differential method for modeling cracks in piezoelectric materials,aiming to simulate fracture behaviors and predict the fracture parameter known as the J-integral accurately.The me...This paper presents a novel element differential method for modeling cracks in piezoelectric materials,aiming to simulate fracture behaviors and predict the fracture parameter known as the J-integral accurately.The method leverages an efficient collocation technique to satisfy traction and electric charge equilibrium on the crack surface,aligning internal nodes with piezoelectric governing equations without needing integration or variational principles.It combines the strengths of the strong form collocation and finite element methods.The J-integral is derived analytically using the equivalent domain integral method,employing Green's formula and Gauss's divergence theorem to transform line integrals into area integrals for solving two-dimensional piezoelectric material problems.The accuracy of the method is validated through comparison with three typical examples,and it offers fracture prevention strategies for engineering piezoelectric structures under different electrical loading patterns.展开更多
The insertion and extraction of lithium ions in active materials lead to significant volumetric deformation,resulting in stresses that drive the mechanical degradation of these materials.This accumulation of mechanica...The insertion and extraction of lithium ions in active materials lead to significant volumetric deformation,resulting in stresses that drive the mechanical degradation of these materials.This accumulation of mechanical degradation ultimately leads to mechanical failure in lithium-ion batteries(LIB).This paper summarizes the experimental characterization techniques used to observe the mechanical degradation of lithium battery cells,electrodes,and particles across macro,micro,and nano scales.Additionally,the mechanical failure model for LIB that spans from the microscopic to the macroscopic scale has been outlined.Finally,we analyze the current challenges and opportunities,including the standardization of battery measurements,the quantification of mechanical failures,and the correlation between mechanical failures and electrochemical performance.展开更多
With the advancement of micro-and nano-scale devices and systems,there has been growing interest in understanding material mechanics at small scales.Nanowires,as fundamental one-dimensional building blocks,offer signi...With the advancement of micro-and nano-scale devices and systems,there has been growing interest in understanding material mechanics at small scales.Nanowires,as fundamental one-dimensional building blocks,offer significant advantages for constructing micro/nano-electro-mechanical systems(MEMS/NEMS)and serve as an ideal platform for studying their size-dependent mechanical properties.This paper reviews the development and current state of nanowire mechanical testing over the past decade.The first part introduces the related issues of nanowire mechanical testing.The second section explores several key topics and the latest research progress regarding the mechanical properties of nanowires,including ultralarge elastic strain,large plastic strain,'smaller is stronger',cold welding,and ductile-to-brittle transition.Finally,the paper envisions future development directions,identifying possible research hotspots and application prospects.展开更多
We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
The elemental segregation,microstructure,and mechanical properties of thermo-mechanical control process(TMCP)treated high-manganese wear-resistant steel(HMWS)were experimentally investigated.Firstly,the initial elemen...The elemental segregation,microstructure,and mechanical properties of thermo-mechanical control process(TMCP)treated high-manganese wear-resistant steel(HMWS)were experimentally investigated.Firstly,the initial elemental segregation in the continuous casting slab of HMWS was characterized using the original position analysis.The results showed that the elemental segregation predominantly occurred near the quarter and the center regions of the slab.The homogenization of manganese(Mn)in the slab was not as obvious as that of other elements after the heating process.Subsequently,a series of hot-rolling tests were carried out on HMWS slab samples under different TMCP conditions,and the elemental segregation and microstructure of the TMCP-treated HMWS were investigated by microscopic analysis methods.The findings demonstrated that the segregations of carbon and silicon were effectively eliminated after the TMCP treatment,while Mn segregation presented a band-shaped arrangement and could be reduced at lower finishing rolling temperatures.The matrix phase of HMWS remained austenite regardless of the TMCP conditions,and the average size of austenite grains increased with the increasing finishing rolling temperature.Carbide particles were observed to form within austenite grains and even along grain boundaries at higher coiling temperatures.Finally,the mechanical tests were performed on the TMCP-treated HMWS at room temperature.The mechanical properties including tensile stress,yield stress,Charpy impact energy,and microhardness were discussed considering the effects of Mn segregation band,microstructure,and carbide precipitation.展开更多
基金supported by the National Natural Science Foundations of China(Nos.12272411 and 42007259)the State Key Laboratory for GeoMechanics and Deep Underground Engineering,the China University of Mining&Technology(No.SKLGDUEK2207)the Department of Science and Technology of Shaanxi Province(Nos.2022KXJ-107 and 2022JC-LHJJ-16).
文摘Underground engineering in extreme environments necessitates understanding rock mechanical behavior under coupled high-temperature and dynamic loading conditions.This study presents an innovative multi-scale cross-platform PFC-FDEM coupling methodology that bridges microscopic thermal damage mechanisms with macroscopic dynamic fracture responses.The breakthrough coupling framework introduces:(1)bidirectional information transfer protocols enabling seamless integration between PFC’s particle-scale thermal damage characterization and FDEM’s continuum-scale fracture propagation,(2)multi-physics mapping algorithms that preserve crack network geometric invariants during scale transitions,and(3)cross-platform cohesive zone implementations for accurate SHTB dynamic loading simulation.The coupled approach reveals distinct three-stage crack evolution characteristics with temperature-dependent density following an exponential model.High-temperature exposure significantly reduces dynamic strength ratio(60%at 800℃)and diminishes strain-rate sensitivity,with dynamic increase factor decreasing from 1.0 to 2.2(25℃)to 1.0-1.3(800℃).Critically,the coupling methodology captures fundamental energy redistribution mechanisms:thermal crack networks alter elastic energy proportion from 75%to 35%while increasing fracture energy from 5%to 30%.Numerical predictions demonstrate excellent experimental agreement(±8%peak stress-strain errors),validating the PFC-FDEM coupling accuracy.This integrated framework provides essential computational tools for predicting complex thermal-mechanical rock behavior in underground engineering applications.
基金Fund supported this work for Excellent Youth Scholars of China(Grant No.52222708)the National Natural Science Foundation of China(Grant No.51977007)+1 种基金Part of this work is supported by the research project“SPEED”(03XP0585)at RWTH Aachen Universityfunded by the German Federal Ministry of Education and Research(BMBF)。
文摘Developing sensorless techniques for estimating battery expansion is essential for effective mechanical state monitoring,improving the accuracy of digital twin simulation and abnormality detection.Therefore,this paper presents a data-driven approach to expansion estimation using electromechanical coupled models with machine learning.The proposed method integrates reduced-order impedance models with data-driven mechanical models,coupling the electrochemical and mechanical states through the state of charge(SOC)and mechanical pressure within a state estimation framework.The coupling relationship was established through experimental insights into pressure-related impedance parameters and the nonlinear mechanical behavior with SOC and pressure.The data-driven model was interpreted by introducing a novel swelling coefficient defined by component stiffnesses to capture the nonlinear mechanical behavior across various mechanical constraints.Sensitivity analysis of the impedance model shows that updating model parameters with pressure can reduce the mean absolute error of simulated voltage by 20 mV and SOC estimation error by 2%.The results demonstrate the model's estimation capabilities,achieving a root mean square error of less than 1 kPa when the maximum expansion force is from 30 kPa to 120 kPa,outperforming calibrated stiffness models and other machine learning techniques.The model's robustness and generalizability are further supported by its effective handling of SOC estimation and pressure measurement errors.This work highlights the importance of the proposed framework in enhancing state estimation and fault diagnosis for lithium-ion batteries.
基金financially supported by the Beijing Natural Science Foundation,China (No.JQ21028)the National Natural Science Foundation of China (Nos.52311530070,52278326,and 52004015)+2 种基金the Major National Science and Technology Project for Deep Earth,China (No.2024ZD1003805)the Project from PetroChina RIPED:the Study on the evolution law of Mineral Structure and Rock Mechanical Properties Under Ultra-High Temperature Conditions (No.2022-KFKT-02)the Fundamental Research Funds for the Central Universities of China (No.FRF-IDRY-20-003,Interdisciplinary Research Project for Young Teachers of USTB)。
文摘Low-to medium-maturity oil shale resources display substantial reserves, offering promising prospects for in-situ conversion inChina. Investigating the evolution of the mechanical properties of the reservoir and caprock under in-situ high-temperature and confine-ment conditions is of considerable importance. Compared to conventional mechanical experiments on rock samples after high-temperat-ure treatment, in-situ high-temperature experiments can more accurately characterize the behavior of rocks in practical engineering,thereby providing a more realistic reflection of their mechanical properties. In this study, an in-situ high-temperature triaxial compressiontesting machine is developed to conduct in-situ compression tests on sandstone at different temperatures(25, 200, 400, 500, and 650℃)and confining pressures(0, 10, and 20 MPa). Based on the experimental results, the temperature-dependent changes in compressivestrength, peak strain, elastic modulus, Poisson's ratio, cohesion, and internal friction angle are thoroughly analyzed and discussed. Resultsindicate that the mass of sandstone gradually decreases as the temperature increases. The thermal conductivity and thermal diffusivity ofsandstone exhibit a linear relationship with temperature. Peak stress decreases as the temperature rises, while it increases with higher con-fining pressures. Notably, the influence of confining pressure on peak stress diminishes at higher temperatures. Additionally, as the tem-perature rises, the Poisson's ratio of sandstone decreases. The internal friction angle also decreases with increasing temperature, with 400℃ acting as the threshold temperature. Interestingly, under uniaxial conditions, the damage stress of sandstone is less affected by tem-perature. However, when the confining pressure is 10 or 20 MPa, the damage stress decreases as the temperature increases. This study en-hances our understanding of the influence of in-situ high-temperature and confinement conditions on the mechanical properties of sand-stone strata. The study also provides valuable references and experimental data that support the development of low-to medium-maturityoil shale resources.
文摘The reaction of Mg^(2+)and 5-{1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl}terephthalic acid(H_(2)L)leads to two metal-organic frameworks,[Mg(L)(DMF)_(2)(H_(2)O)_(2)]_(2)·5DMF·2H_(2)O(1)with a 1D structure and[Mg_(2)(L)_(2)(DMSO)_(3)(H_(2)O)](2)with a 2D(4,4)-net structure.Interestingly,the two compounds exhibit distinct luminescent responses to external mechanical stimuli.1 exhibited exceptional resistance mechanical chromic luminescence(RMCL),which can be attributed to the predominant hydrogen bonds and the presence of high-boiling-point solvent molecules within its structure.2 had a reversible MCL property,which can be attributed to the dominantπ-πweak interactions,coupled with the reversible destruction/restoration of its crystallinity under grinding/fumigation.CCDC:2410963,1;2410964,2.
基金National Natural Science Foundation of China(U2241242)National Key R&D Program of China(2023YFB3812000,2021YFA0716502)。
文摘The accepted doping ion in Ti^(4+)-site of PbZr_(y)Ti_(1–y)O_(3)(PZT)-based piezoelectric ceramics is a well-known method to increase mechanical quality factor(Q_(m)),since the acceptor coupled by oxygen vacancy becomes defect dipole,which prevents the domain rotation.In this field,a serious problem is that generally,Qm decreases as the temperature(T)increases,since the oxygen vacancies are decoupled from the defect dipoles.In this work,Q_(m) of Pb_(0.95)Sr_(0.05)(Zr_(0.53)Ti_(0.47))O_(3)(PSZT)ceramics doped by 0.40%Fe_(2)O_(3)(in mole)abnormally increases as T increases,of which the Qm and piezoelectric coefficient(d_(33))at room temperature and Curie temperature(TC)are 507,292 pC/N,and 345℃,respectively.The maximum Qm of 824 was achieved in the range of 120–160℃,which is 62.52%higher than that at room temperature,while the dynamic piezoelectric constant(d_(31))was just slightly decreased by 3.85%.X-ray diffraction(XRD)and piezoresponse force microscopy results show that the interplanar spacing and the fine domains form as temperature increases,and the thermally stimulated depolarization current shows that the defect dipoles are stable even the temperature up to 240℃.It can be deduced that the aggregation of oxygen vacancies near the fine domains and defect dipole can be stable up to 240℃,which pins domain rotation,resulting in the enhanced Q_(m) with the increasing temperature.These results give a potential path to design high Q_(m) at high temperature.
基金the Puncak RM for the project under the grant 6733204-13069 to carry out the experiments。
文摘Graphene nanoplatelets(GNPs)have attracted tremendous interest due to their unique properties and bonding capabilities.This study focuses on the effect of GNP dispersion on the mechanical,thermal,and morphological behavior of GNP/epoxy nanocomposites.This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance.A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites.Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix.The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite.The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step,producing well-dispersed nanocomposites with improved mechanical properties.Particularly,the nanocomposites at a low GNP loading of 0.1 wt%,demonstrate superior mechanical strength,as shown by increased tensile properties,including improved Young's modulus(1.86 GPa),strength(57.31 MPa),and elongation at break(4.98).The nanocomposite with 0.25 wt%GNP loading performs better,according to the viscoelastic analysis and flexural properties(113.18 MPa).Except for the nanocomposite with a 0.5 wt%GNP loading,which has a higher thermal breakdown temperature,the thermal characteristics do not significantly alter.The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization.The findings help with filler selection and identifying the best dispersion approach,which improves mechanical performance.The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites.In fields like aerospace,automotive,and electronics where higher mechanical performance and functionality are required,GNPs'improved mechanical properties and successful dispersion present exciting potential.
基金funded by the National Natural Science Foundation of China(Nos.52422403 and U22A20166)the Deep Earth Probe and Mineral Resources Exploration-National Science and Technology Major Project(No.2024ZD1003903)+1 种基金the Department of Science and Technology of Guangdong Province(No.2019ZT08G315)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515012654).
文摘Understanding the mechanical behavior of diagenetic mineral granules and interfaces in granite provides essential experimental references for constructing micromechanical models of granite.The micromechanical behavior of Yanshanian granite is investigated using scanning electron microscopy-energy dispersive spectroscopy(SEM-EDS)and nanoindentation tests.The results demonstrate transitional mechanical properties at mineral interfaces.The elastic modulus and hardness exhibit intermediate values between adjacent mineral phases.The higher plasticity indices at the interfaces suggest higher plastic deformation capacity of hard-phase minerals in these regions.Additionally,fracture toughness measurements of minerals and interfaces were obtained,with interfacial values ranging from 0.90 to 1.63 MPa·m^(0.5).The analysis of mechanical property relationships shows a significant positive linear correlation between rock-scale elastic modulus and fracture toughness.However,this correlation is substantially lower at the mineral scale,demonstrating a scale effect in the relationship of different mechanical properties.
基金support from the Science and Technology Key Project of Beijing Polytechnic(Project Leader:Jinru Ma,No.2024X008-KXZ).
文摘With the economic and social development of the country,vocational education is playing an increasingly significant role in cultivating highly skilled talents.However,the mechanical drawing courses in vocational colleges still face numerous challenges in the teaching process,such as outdated textbook content,inadequate practical resources,weak teaching staff,and low student interest.This paper aims to explore these issues and propose corresponding coping strategies.The findings of this study not only provide specific improvement suggestions for vocational colleges but also emphasize the importance of these strategies in enhancing students’comprehensive abilities and promoting the development of vocational education.By addressing these challenges,this paper contributes to the enhancement of teaching quality and the overall advancement of vocational skills education.
文摘The unbreakable doll performance at Tang Dynasty Night City has become extremely popular,sparking a wave of enthusiasm online.In the performance,actors dressed in elegant Tang Dynasty attire appear as if they have stepped out of a historical painting,gracefully dancing on the unbreakable doll apparatus.Every gesture and expression exudes the unparalleled elegance of the Tang Dynasty.This paper primarily analyzes the mechanical principles behind the Tang Dynasty Night City’s Unbreakable Doll Performance,starting with structural design to examine its mechanical principles and summarize its dynamic mechanical control mechanisms.
基金financially supported by the Liaoning Province Applied Fundamental Research Program (No.2023JH2/101700039)Liaoning Province Natural Science Foundation (No.2023-MSLH-328).
文摘Metallic lattice structures represent advanced architected materials delivering exceptional properties with promising lightweight potential.With the rapid advancement of additive manufacturing,these structures have garnered increasing research interest.However,most metallic lattice structures generally exhibit anisotropic characteristics,which limits their application ranges.Additionally,a limited number of studies have successfully developed precise mechanical models,which have undergone experimental validation,for the purpose of describing the mechanical response exhibited by additively manufactured metallic lattice structures.In this study,Kelvin lattice structures with varying porosities were systematically designed and fabricated using laser powder bed fusion(LPBF)technology.By integrating finite element simulations with experimental characterization,an enhanced mechanical model was developed through a modification of the Gibson-Ashby model,providing an accurate quantitative description of the relationship between porosity and mechanical properties.The results show that the revised mechanical model can accurately describe the relationship between the geometric parameters and properties of metallic lattice structures.Specifically,the designed Kelvin lattice structures exhibit a smooth stress-strain curve with an obvious yield platform,demonstrating isotropic mechanical properties in all the three spatial directions.This enhances their suitability for complex loading conditions.Meanwhile,the microstructure and manufacturing accuracy of the Kelvin lattice structures were observed and analyzed by micro computed tomography.The results show that the fabricated metallic lattice structures achieved precise dimensional control and optimal densification.This study presents the complete process involved in modeling the Kelvin structure,including its conceptualization,manufacturing,implementation,and ultimately,disposal.
基金Sponsored by Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515111166)Development and Reform Commission of Shenzhen(Grant No.XMHT20220103004)+1 种基金Shenzhen Natural Science Fund(Grant No.GXWD20231130100351002)National Natural Science Foundation of China(Grant No.11932005).
文摘Multi⁃field coupling problems involving species transport,heat transfer,substance transformation,and mechanical deformation are prevalent in various scenarios,such as the curing of early⁃age concretes,the response of soft materials,the oxidation of metals,the lithiation and delithiation of lithium⁃ion batteries,and the self⁃healing of biological tissues.Thermo⁃chemo⁃mechanical coupling dynamics are common characteristics of these problems,making theoretical studies on such processes of significant importance.This study offers a thorough review of advanced theoretical models that address thermo⁃chemo⁃mechanical behavior of solid materials within the theoretical framework of non⁃equilibrium thermodynamics.First,we outline the thermo⁃chemo⁃mechanical coupling phenomena observed in various application scenarios.Then,the theoretical developments of classical continuum mechanics include the phase field method and peridynamics in the contexts of thermo⁃mechanical coupling,chemo⁃mechanical coupling,and thermo⁃chemo⁃mechanical coupling,respectively.Finally,challenges faced by thermo⁃chemo⁃mechanical coupling research are highlighted and prospects and directions for this field are also outlined.This paper helps to understand the history and trends in the development of thermo⁃chemo⁃mechanical coupling theory.
文摘On May 9,2025 on the campus of the University of Science and Technology of China(USTC),Chinese Academy of Sciences(CAS),an exhibition was unveiled to celebrate the UN International Year of Quantum Science and Technology(IYQ)-a one-year-long worldwide event in memory of the founding of quantum mechanics(QM).
基金supported by the project from the Exploration and Development Research Institute of PetroChina Daqing Oilfield Companyfinancial support from the research by the National Natural Science Foundation of China(42402148)+1 种基金Sichuan Provincial Fund(24NSFSC4997)Guizhou Outstanding Young Science and Technology Talent Program(YQK[2023]012).
文摘Microstructural heterogeneity of low-permeability sandstone roofs of deep unmineable coal seams due to diagenesis significantly affects rock mechanical behavior,greatly impacting the sealing potential of in situ CO_(2) sequestration and the structural stability of the geological formation.However,little is known about how the microstructure of different mineral groups influences the multiscale mechanical behavior of deep sandstone.This study proposes a new method for quantitatively characterizing the multiscale mechanical properties of low-permeability sandstone and shows the mechanisms responsible for mechanical failure at the micro-,meso-,and macroscale.Triaxial compression tests and targeted nanoindentation tests were conducted to assess the micro-and macroscale mechanical properties of different types of sandstone.The micro-and macroscale experiments were coupled with numerical simulations of compression using a unified cohesive model based on Voronoi polygons to clarify the multiscale mechanical behavior.The results indicate that quartz,the primary mineral component of the sandstones examined,exhibits the strongest micromechanical properties,followed by feldspar,calcite,and clay minerals.Compared to polycrystalline quartz,monocrystalline quartz has a more stable microstructure and is mechanically stronger.The macro-mechanical properties of tight sandstone samples are weakened by increased microstructural inhomogeneity and larger grain size.This leads to a higher likelihood of splitting damage,characterized by a high degree of discrete and weak stress sensitivity.The major conclusion is that the positive rhythm lithofacies of medium-grained sandstone to siltstone are the most favorable for efficient CO_(2) sequestration in deep unmineable coal seams.
基金support by the National Natural Science Foundation of China(Grant Nos.U23A20546 and 52271010)the Chinese National Natural Science Fund for Distinguished Young Scholars(Grant No.52025015)the Natural Science Foundation of Tianjin City(No.21JCZDJC00510).
文摘1.Introduction The strength-ductility trade-offdilemma has long been a per-sistent challenge in Al matrix composites(AMCs)[1,2].This is-sue primarily arises from the agglomeration of reinforcements at the grain boundaries(GBs),which restricts local plastic flow dur-ing the plastic deformation and leads to stress concentration[3,4].Recently,the development of concepts aimed at achieving hetero-geneous grain has emerged as a promising approach for enhanc-ing comprehensive mechanical properties[5,6].
基金supported by the Australian Research Council(Grant No.IC190100020)the Australian Research Council Indus〓〓try Fellowship(Grant No.IE230100435)the National Natural Science Foundation of China(Grant Nos.12032014 and T2488101)。
文摘The integration of physics-based modelling and data-driven artificial intelligence(AI)has emerged as a transformative paradigm in computational mechanics.This perspective reviews the development and current status of AI-empowered frameworks,including data-driven methods,physics-informed neural networks,and neural operators.While these approaches have demonstrated significant promise,challenges remain in terms of robustness,generalisation,and computational efficiency.We delineate four promising research directions:(1)Modular neural architectures inspired by traditional computational mechanics,(2)physics informed neural operators for resolution-invariant operator learning,(3)intelligent frameworks for multiphysics and multiscale biomechanics problems,and(4)structural optimisation strategies based on physics constraints and reinforcement learning.These directions represent a shift toward foundational frameworks that combine the strengths of physics and data,opening new avenues for the modelling,simulation,and optimisation of complex physical systems.
基金Financial support of this work by the Technology Development program of China(Grant No.2022204B003)National Natural Science Foundation of China(12272083 and 12172078)the Fundamental Research Funds for the Central Universities(DUT24YJ136)is gratefully acknowledged.
文摘This paper presents a novel element differential method for modeling cracks in piezoelectric materials,aiming to simulate fracture behaviors and predict the fracture parameter known as the J-integral accurately.The method leverages an efficient collocation technique to satisfy traction and electric charge equilibrium on the crack surface,aligning internal nodes with piezoelectric governing equations without needing integration or variational principles.It combines the strengths of the strong form collocation and finite element methods.The J-integral is derived analytically using the equivalent domain integral method,employing Green's formula and Gauss's divergence theorem to transform line integrals into area integrals for solving two-dimensional piezoelectric material problems.The accuracy of the method is validated through comparison with three typical examples,and it offers fracture prevention strategies for engineering piezoelectric structures under different electrical loading patterns.
基金funded by the Key Research and Development Project of Guangdong Province(No.2023B0909050004)the National Natural Science Foundation of China(No.12402214).
文摘The insertion and extraction of lithium ions in active materials lead to significant volumetric deformation,resulting in stresses that drive the mechanical degradation of these materials.This accumulation of mechanical degradation ultimately leads to mechanical failure in lithium-ion batteries(LIB).This paper summarizes the experimental characterization techniques used to observe the mechanical degradation of lithium battery cells,electrodes,and particles across macro,micro,and nano scales.Additionally,the mechanical failure model for LIB that spans from the microscopic to the macroscopic scale has been outlined.Finally,we analyze the current challenges and opportunities,including the standardization of battery measurements,the quantification of mechanical failures,and the correlation between mechanical failures and electrochemical performance.
基金supported by NSFC/RGC Joint Research Scheme(No.N_HKU159/22)Research Grants Council of the Hong Kong Special Administrative Region,China under Grant No.RFS2021-1S05.
文摘With the advancement of micro-and nano-scale devices and systems,there has been growing interest in understanding material mechanics at small scales.Nanowires,as fundamental one-dimensional building blocks,offer significant advantages for constructing micro/nano-electro-mechanical systems(MEMS/NEMS)and serve as an ideal platform for studying their size-dependent mechanical properties.This paper reviews the development and current state of nanowire mechanical testing over the past decade.The first part introduces the related issues of nanowire mechanical testing.The second section explores several key topics and the latest research progress regarding the mechanical properties of nanowires,including ultralarge elastic strain,large plastic strain,'smaller is stronger',cold welding,and ductile-to-brittle transition.Finally,the paper envisions future development directions,identifying possible research hotspots and application prospects.
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
基金support for this research provided by the High-end Foreign Experts Recruitment Plan of China(Grant No.G2022105011L).
文摘The elemental segregation,microstructure,and mechanical properties of thermo-mechanical control process(TMCP)treated high-manganese wear-resistant steel(HMWS)were experimentally investigated.Firstly,the initial elemental segregation in the continuous casting slab of HMWS was characterized using the original position analysis.The results showed that the elemental segregation predominantly occurred near the quarter and the center regions of the slab.The homogenization of manganese(Mn)in the slab was not as obvious as that of other elements after the heating process.Subsequently,a series of hot-rolling tests were carried out on HMWS slab samples under different TMCP conditions,and the elemental segregation and microstructure of the TMCP-treated HMWS were investigated by microscopic analysis methods.The findings demonstrated that the segregations of carbon and silicon were effectively eliminated after the TMCP treatment,while Mn segregation presented a band-shaped arrangement and could be reduced at lower finishing rolling temperatures.The matrix phase of HMWS remained austenite regardless of the TMCP conditions,and the average size of austenite grains increased with the increasing finishing rolling temperature.Carbide particles were observed to form within austenite grains and even along grain boundaries at higher coiling temperatures.Finally,the mechanical tests were performed on the TMCP-treated HMWS at room temperature.The mechanical properties including tensile stress,yield stress,Charpy impact energy,and microhardness were discussed considering the effects of Mn segregation band,microstructure,and carbide precipitation.
