Inverse design of advanced materials represents a pivotal challenge in materials science.Leveraging the latent space of Variational Autoencoders(VAEs)for material optimization has emerged as a significant advancement ...Inverse design of advanced materials represents a pivotal challenge in materials science.Leveraging the latent space of Variational Autoencoders(VAEs)for material optimization has emerged as a significant advancement in the field of material inverse design.However,VAEs are inherently prone to generating blurred images,posing challenges for precise inverse design and microstructure manufacturing.While increasing the dimensionality of the VAE latent space can mitigate reconstruction blurriness to some extent,it simultaneously imposes a substantial burden on target optimization due to an excessively high search space.To address these limitations,this study adopts a Variational Autoencoder guided Conditional Diffusion Generative Model(VAE-CDGM)framework integrated with Bayesian optimization to achieve the inverse design of composite materials with targeted mechanical properties.The VAE-CDGM model synergizes the strengths of VAEs and Denoising Diffusion Probabilistic Models(DDPM),enabling the generation of high-quality,sharp images while preserving a manipulable latent space.To accommodate varying dimensional requirements of the latent space,two optimization strategies are proposed.When the latent space dimensionality is excessively high,SHapley Additive exPlanations(SHAP)sensitivity analysis is employed to identify critical latent features for optimization within a reduced subspace.Conversely,direct optimization is performed in the low-dimensional latent space of VAE-CDGM when dimensionality is modest.The results demonstrate that both strategies accurately achieve the targeted design of composite materials while circumventing the blurred reconstruction flaws of VAEs,which offers a novel pathway for the precise design of advanced materials.展开更多
In the context of the global energy low-carbon transition,phase change energy storage technology becomes a key technology to solve the problem of intermittent renewable energy.Oriented phase change composites(OCPCMs)r...In the context of the global energy low-carbon transition,phase change energy storage technology becomes a key technology to solve the problem of intermittent renewable energy.Oriented phase change composites(OCPCMs)receive widespread attention in practical energy storage applications due to their unique oriented thermally conductive structure,which achieves significant thermal conductivity enhancement in specific directions while retaining the high energy storage capacity of the phase change components.This review systematically summarizes the overall analysis of OCPCMs from synthesis and preparation to application scenarios in recent years.Herein,we introduce the analysis of the heat transfer mechanism of the materials and explore the advantages of the oriented structure in OCPCMs in the heat transfer behavior from a bionic perspective.We then focus on summarizing and generalizing the methods for preparing OCPCMs,giving suggestions for suitable methods according to different scenarios.Besides,we discuss the application of finite element simulation methods to the monitoring of the thermal management behavior of OCPCMs,and look into the potential future application areas of such materials.Finally,it is hoped that this review will provide guidance for the academic community in developing high-performance OCPCMs.展开更多
Ultrasonic-Assisted Grinding(UAG)is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites(CMCs).Nevertheless,analyzing the material removal process of CMCs with ...Ultrasonic-Assisted Grinding(UAG)is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites(CMCs).Nevertheless,analyzing the material removal process of CMCs with multidirectional structure during UAG is challenging,impeding the progress and improvement of the UAG process.This work examined the impact of ultrasonic vibration on the dynamic mechanical characteristics during processing.Additionally,we experimentally elucidated the material removal mechanism of CMCs during the scratching process under the influence of vertical vibration.The results indicate that the introduction of ultrasonic vibration causes a strain rate effect,resulting in a modification of the material removal mechanism,subsequently impacting the processing quality.Ultrasonic vibration increases the dynamic strength and brittleness of the fibers in CMCs,leading to more cracks at fracture,which changes from the original bending fracture to shear fracture.In addition,ultrasonic vibration can effectively inhibit the impact of scratching depth and anisotropy on the removal mechanism of CMCs,resulting in a more uniform surface of CMCs after processing.展开更多
Latent heat thermal energy storage(TES)effectively reduces the mismatch between energy supply and demand of renewable energy sources by the utilization of phase change materials(PCMs).However,the low thermal conductiv...Latent heat thermal energy storage(TES)effectively reduces the mismatch between energy supply and demand of renewable energy sources by the utilization of phase change materials(PCMs).However,the low thermal conductivity and poor shape stability are the main drawbacks in realizing the large-scale application of PCMs.Promisingly,developing composite PCM(CPCM)based on porous supporting mate-rial provides a desirable solution to obtain performance-enhanced PCMs with improved effective thermal conductivity and shape stability.Among all the porous matrixes as supports for PCM,three-dimensional carbon-based porous supporting material has attracted considerable attention ascribing to its high ther-mal conductivity,desirable loading capacity of PCMs,and excellent chemical compatibility with various PCMs.Therefore,this work systemically reviews the CPCMs with three-dimensional carbon-based porous supporting materials.First,a concise rule for the fabrication of CPCMs is illustrated in detail.Next,the experimental and computational research of carbon nanotube-based support,graphene-based support,graphite-based support and amorphous carbon-based support are reviewed.Then,the applications of the shape-stabilized CPCMs including thermal management and thermal conversion are illustrated.Last but not least,the challenges and prospects of the CPCMs are discussed.To conclude,introducing carbon-based porous materials can solve the liquid leakage issue and essentially improve the thermal conductivity of PCMs.However,there is still a long way to further develop a desirable CPCM with higher latent heat capacity,higher thermal conductivity,and more excellent shape stability.展开更多
Composites made from biopolymers and natural fibers are gaining popularity as alternative sustainable structural materials.Biopolyesters including polylactic acid(PLA),polybutylene succinate(PBS),and polyhydroxyalkano...Composites made from biopolymers and natural fibers are gaining popularity as alternative sustainable structural materials.Biopolyesters including polylactic acid(PLA),polybutylene succinate(PBS),and polyhydroxyalkanoate(PHA),when mixed with natural fibers such as kenaf,hemp,and jute,provide an environmentally acceptable alternative to traditional fossil-based materials.This article examines current research on developments in the integration of biopolymers with natural fibers,with a focus on enhancing mechanical,thermal,and sustainability.Innovative approaches to surface treatment of natural fibers,such as biological and chemical treatments,have demonstrated enhanced adhesion with biopolymer matrices,increasing attributes such as tensile strength and rigidity.Furthermore,nano filling technologies such as nanocellulose and nanoparticles have improved the attributes of multifunctional composites,including heat conductivity and moisture resistance.According to performance analysis,biopolymernatural fiber-based composites may compete with synthetic composites in construction applications,particularly in lightweight buildings and automobiles.However,significant issues such as degradation in humid settings and longtermendurancemust be solved.To support a circular economy,solutions involve the development ofmoisture-resistant polymers and composite recycling technology.This article examines current advancements and identifies problems and opportunities to provide insight into the future direction of more inventive and sustainable biocomposites,and also the dangers they pose to green technology and industrial materials.These findings are significant in terms of the development of building materials which are not only competitive but also contribute to global sustainability.展开更多
Iron-based metal matrix composites(IMMCs)have attracted significant research attention due to their high specific stiffness and strength,making them potentially suitable for various engineering applications.Microstruc...Iron-based metal matrix composites(IMMCs)have attracted significant research attention due to their high specific stiffness and strength,making them potentially suitable for various engineering applications.Microstructural design,including the selection of reinforcement and matrix phases,the reinforcement volume fraction,and the interface issues are essential factors determining the engineering performance of IMMCs.A variety of fabrication methods have been developed to manufacture IMMCs in recent years.This paper reviews the recent advances and development of IMMCs with particular focus on microstructure design,fabrication methods,and their engineering performance.The microstructure design issues of IMMC are firstly discussed,including the reinforcement and matrix phase selection criteria,interface geometry and characteristics,and the bonding mechanism.The fabrication methods,including liquid state,solid state,and gas-mixing processing are comprehensively reviewed and compared.The engineering performance of IMMCs in terms of elastic modulus,hardness and wear resistance,tensile and fracture behavior is reviewed.Finally,the current challenges of the IMMCs are highlighted,followed by the discussion and outlook of the future research directions of IMMCs.展开更多
Untreated water environments encourage the emergence of pathogenic microorganisms,which pose a significant risk to human health and sustainable development.Antimicrobial technologies in advanced photothermal materials...Untreated water environments encourage the emergence of pathogenic microorganisms,which pose a significant risk to human health and sustainable development.Antimicrobial technologies in advanced photothermal materials offer a promising alternative strategy for solving water disinfection challenges.This technology effectively destroys bacterial biofilms by designing materials with controlled photothermal properties.Despite the potential of this technology,there is a lack of comprehensive reviews on the application of photothermal materials in water disinfection.The aim of this paper is to provide a comprehensive and up-to-date overview of the research and application of photothermal materials in water disinfection.It focuses on composites in photothermal materials,elucidates their basic mechanisms and sterilization properties,and provides a systematic and detailed overview of their recent progress in the field.The goal of this review is to offer insights into the future design of photothermal materials and to propose strategies for their practical application in disinfection processes.展开更多
Flexible electronic skin(E-skin)sensors offer innovative solutions for detecting human body signals,enabling human-machine interactions and advancing the development of intelligent robotics.Electrospun nanofibers are ...Flexible electronic skin(E-skin)sensors offer innovative solutions for detecting human body signals,enabling human-machine interactions and advancing the development of intelligent robotics.Electrospun nanofibers are particularly wellsuited for E-skin applications due to their exceptional mechanical properties,tunable breathability,and lightweight nature.Nanofiber-based composite materials consist of three-dimensional structures that integrate one-dimensional polymer nanofibers with other functional materials,enabling efficient signal conversion and positioning them as an ideal platform for next-generation intelligent electronics.Here,this review begins with an overview of electrospinning technology,including far-field electrospinning,near-field electrospinning,and melt electrospinning.It also discusses the diverse morphologies of electrospun nanofibers,such as core-shell,porous,hollow,bead,Janus,and ribbon structure,as well as strategies for incorporating functional materials to enhance nanofiber performance.Following this,the article provides a detailed introduction to electrospun nanofiber-based composite materials(i.e.,nanofiber/hydrogel,nanofiber/aerogel,nanofiber/metal),emphasizing their recent advancements in monitoring physical,physiological,body fluid,and multi-signal in human signal detection.Meanwhile,the review explores the development of multimodal sensors capable of responding to diverse stimuli,focusing on innovative strategies for decoupling multiple signals and their state-of-the-art advancements.Finally,current challenges are analyzed,while future prospects for electrospun nanofiber-based composite sensors are outlined.This review aims to advance the design and application of next-generation flexible electronics,fostering breakthroughs in multifunctional sensing and health monitoring technologies.展开更多
This paper reviews the research status and development trends of lattice-foam composite structural materials.It introduces the characteristics and applications of lattice metallic materials and metallic foam materials...This paper reviews the research status and development trends of lattice-foam composite structural materials.It introduces the characteristics and applications of lattice metallic materials and metallic foam materials among ultra-light porous materials,and points out their respective shortcomings.Subsequently,it elaborates on the research progress of lattice-foam composite structural materials at home and abroad,including the research achievements of research teams such as Xi’an Jiaotong University and the University of Virginia in the United States.Then,the key technologies in the preparation process of lattice-foam composite structural materials are discussed in detail,such as the rapid prototyping technology for special-shaped parts of porous materials,the friction stir welding technology for metallic foams,and the large-area joining and composite technology between the core and face sheets of composite structures.Finally,the research on lattice-foam composite structural materials is summarized and prospected.展开更多
Sodium ion batteries(SIBs)are one of the most prospective energy storage devices recently.Carbon materials have been commonly used as anode materials for SIBs because of their wide sources and low price.However,pure c...Sodium ion batteries(SIBs)are one of the most prospective energy storage devices recently.Carbon materials have been commonly used as anode materials for SIBs because of their wide sources and low price.However,pure carbon materials still have the disadvantage of low theoretical capacity.New design and preparation strategies for carbon-based composites can overcome the problems.Based on the analysis of Na^(+)storage mechanism of carbon-based composite materials,the factors influencing the performance of SIBs are discussed.Adjustment methods for improving the electrochemical performance of electrodes are evaluated in detail,including carbon skeleton design and composite material selection.Some advanced composite materials,i.e.,carbon-conversion composite and carbon-MXene composite,are also being explored.New advances in flexible electrodes based on carbon-based composite on flexible SIBs is investigated.The existing issues and future issues of carbon-based composite materials are discussed.展开更多
In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applic...In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.展开更多
A solid,fast-dissolving sodium silicate was used as an alkaline activator.Granulated blast furnace slag(GGBS),metakaolin(MK),and steel slag(SS)were used as the cementious components to prepare a ternary composite ceme...A solid,fast-dissolving sodium silicate was used as an alkaline activator.Granulated blast furnace slag(GGBS),metakaolin(MK),and steel slag(SS)were used as the cementious components to prepare a ternary composite cementitious material known as alkali-activated steel slag composite cementitious material(ASCM)by the"one-step method".The impacts of cementitious components,alkali activator modulus,and Na_(2)O%on the mechanical strength were investigated,and the hydration products and hydration kinetics of ASCM were analyzed.The experimental results reveal that XRD,FTIR,SEM,EDS,and exothermic heat of hydration show that when GGBS:MK:SS=60wt%:10wt%:30wt%,the activator modulus is 1.2,and the alkali content is 5.5wt%,the 28 d flexural strength of ASCM mortar is 12.6 MPa,and the compressive strength is 53.3 MPa,the hydration products consist of C-S-H gel/C-A-S-H gel,mullite(3Al_(2)O_(3)-2SiO_(2)),calcite(CaCO_(3)),quartz,etc.ASCM has a large initial hydration exotherm rate but a small cumulative exotherm.展开更多
Silicon carbide/pyrolytic carbon (SiC/PyC) composite materials with excellent performance of self-lubrication and wear resistance were prepared on SiC substrates by electromagnetic-field-assisted chemical vapor infilt...Silicon carbide/pyrolytic carbon (SiC/PyC) composite materials with excellent performance of self-lubrication and wear resistance were prepared on SiC substrates by electromagnetic-field-assisted chemical vapor infiltration (CVI). The composition and microstructure of the SiC/PyC materials were investigated in detail by XRD, SEM and EDS, etc. The effects of the deposition temperature on the section features and wear resistance of the SiC/PyC were studied. The results show that the PyC layers were deposited onto SiC substrates spontaneously at a lower deposition temperature. The SiC substrates deposited with PyC can significantly reduce the wear rate of the self-dual composite materials under dry sliding condition. The wear tests suggest that the SiC/PyC composite materials own a better wear resistance property when the deposition temperature is 800 °C, and the wear rate is about 64.6% of that without the deposition of PyC.展开更多
Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique...Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy（EDXS）, anode polarization curves, quasi-stationary polarization（Tafel） curves, electrochemical impedance spectroscopy（EIS）, scanning electron microscopy（SEM）, and X-ray diffraction（XRD）. Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential（0.610 V at 500 A/m2） for oxygen evolution, the best electrocatalytic activity, the longest service life（360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2）, and the lowest cell voltage（2.75 V at 500 A/m2）. Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed.展开更多
KIT-5/Beta composite supports were synthesized using an in situ self-assembly hydrothermal method,and NiW/KIT-5/Beta catalysts were prepared by impregnation.A series of characterization techniques were utilized to eva...KIT-5/Beta composite supports were synthesized using an in situ self-assembly hydrothermal method,and NiW/KIT-5/Beta catalysts were prepared by impregnation.A series of characterization techniques were utilized to evaluate the influence of varying hydrothermal synthesis temperatures on the physicochemical properties of both the KIT-5/Beta supports and the resulting catalysts.The catalytic performances of catalysts were evaluated under reaction conditions of 320℃,4 MPa H_(2)pressure,and a weight hourly space velocity(WHSV)of 4.8 h^(-1)for hydrodenitrogenation(HDN)of quinoline.The results indicated that the specific surface area and pore structure of the materials could be effectively regulated by adjusting the hydrothermal synthesis temperature,which in turn influenced the number of active sites on the catalyst.The NiW/KB-125 catalyst,synthesized at 125℃,presented the highest quinoline HDN efficiency(96.8%),which can be attributed to its favorable pore channel structure,greater Brønsted acid number,higher degree of metal sulfidation(80.12%)and appropriate metal-support interaction(MSI).展开更多
Electroslag remelting(ESR) is an important metallurgical process for producing high-purity materials with homogeneous compositions and sound microstructures,and its typical products are ingots or simple castings.The c...Electroslag remelting(ESR) is an important metallurgical process for producing high-purity materials with homogeneous compositions and sound microstructures,and its typical products are ingots or simple castings.The core principle involves the resistive melting of a consumable electrode within a slag pool,followed by the refining of molten metal droplets as they traverse the slag,and subsequent sequential solidification in a water-cooled mold.However,conventional ESR processes face limitations in producing large or complex-shaped components,enhancing production efficiency,achieving highly specialized microstructures,and meeting ultra-high purity demands for advanced applications.Advanced composite ESR technologies have been developed to overcome these limitations by innovatively modifying key process aspects.For instance,electrode systems are improved using vibration,rotation,or multiple electrodes.Enhanced mold design and solidification control are achieved through techniques including conductive molds,mold rotation,and ingot withdrawal.Precise control of the process is realized through the use of protective gas,vacuum,or elevated pressure,as well as the application of external fields such as magnetic fields or ultrasonic vibration.This review comprehensively summarizes these advanced techniques,examining their principles and characteristics,and discussing their specific advantages and challenges.展开更多
Typically used thermal insulation materials such as foam insulation and fibreglass may pose notable health risks and environmental impacts thereby resulting in respiratory irritation andwaste disposal issues,respectiv...Typically used thermal insulation materials such as foam insulation and fibreglass may pose notable health risks and environmental impacts thereby resulting in respiratory irritation andwaste disposal issues,respectively.While these materials are affordable and display good thermal insulation,their unsustainable traits pertaining to an intensive manufacturing process and poor disposability are major concerns.Alternative insulation materials with enhanced sustainable characteristics are therefore being explored,and one type of material which has gained notable attention owing to its low carbon footprint and low thermal conductivity is natural fibre.Among the few review studies conducted on Natural Fibre Reinforced Composite(NFRC)insulation boards,the multitude of factors and underlying mechanisms affecting their thermal conductivity performance have been sparsely covered.This review study aimed to address this gap by providing a holistic overview of some of the key intrinsic and extrinsic factors affecting the thermal conductivity performance of NFRCs.Key intrinsic factors pertaining to the microstructural features and to the physico-mechanical traits of NFRCs,namely the fibre lumen size,α,and the fibre-matrix thermal conductivity ratio,β,respectively,were found to largely affect the Transverse Thermal Conductivity(TTC)in NFRC boards.Extrinsic factors,which were found to indirectly affect NFRCs’thermal conductivity,such as fibre pre-processing,composite manufacturing and environmental factors,were also covered.Some of the noteworthy NFRC featureswhich were found to affect their thermal conductivity are volume fraction of fibres,bulk density and porosity.The findings of this study highlight the need for additional research investigation to address the foregoing limitations observed in NFRC thermal insulation boards by considering appropriate natural fibres,composition and fabrication techniques.The fabrication of high-grade NFRC boards,which will display an optimum balance between enhanced thermal insulation and long-term durability performance,could further replace conventionally used thermal insulation boards in the modern building and construction industry.展开更多
Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreat...Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreatments,an inert environment,and long hours of physical ball milling for high homogeneity and synergistic effects.CaH_(2)also inhibits the hydrolysis reaction by forming its products on the Al/Si surface,which hinders the direct utilization of composites.This work represents the first investigation of NaH-CaH_(2)(Al/Si)fuel composites,which greatly overcome these limitations and can be directly used for on-site hydrogen generation and proton exchange membrane(PEM)fuel cells.The NaH-CaH_(2)(Al/Si)fuel composites were prepared by using a straightforward mixing method with variable composition ratios,showing high H_(2)yield and fuel cell(FC)performance.NaH addition provides the bridge effect,which opens up a new way to enable efficient hydrolysis and greatly enhances the hydrolysis activity of CaH_(2)/(Al/Si)composites.The novel fuel composites(NaH-CaH_(2)/Al)have extraordinary FC performance and a 0.42 W/cm2 peak power density greater than commercial hydrogen generators.It provides high H_(2)yield 84.4%for NaH-CaH_(2)/Al and 82%for NaH-CaH_(2)/Si compared to NaOH-CaH_(2)(Al/Si),NaCl-CaH_(2)(Al/Si),and KCl-CaH_(2)(Al/Si)composites.The NaH bridge effect hinders the direct water contact and stops the formation of Ca(OH)2 around Al/Si,which provides adequate pathways for the CaH_(2)(Al/Si)hydrolysis.The impressive capabilities of novel fuel composites are anticipated to offer practical uses in fuel cells,automobile applications,and portable/on-board H_(2)generation.展开更多
In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order hom...In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.展开更多
In order to adjust some properties of cement grout or concrete,some mineral admixtures are usually added in the preparation.Admixtures can reduce the cement consumption and save the cost,and also adjust the workabilit...In order to adjust some properties of cement grout or concrete,some mineral admixtures are usually added in the preparation.Admixtures can reduce the cement consumption and save the cost,and also adjust the workability of the material,improve the strength and durability of the cement stone,or reduce hydration heat of the composite cement.At present,the content of fly ash or slag is generally less than 50%among the composite cementitious materials that have been studied more,but there is little research on composite cementitious materials with large mineral admixture.In this paper,XRD,SEM,and adiabatic temperature rise tests were used to discuss hydration products and mechanism of composite cement grout with 90%content of fly ash and slag.The results show that the hydration of the composite cement grout is an alkali-activated hydration reaction,and the hydration products are mainly amorphous substances such as hydrated calcium silicate or hydrated calcium aluminate gel.The hydration reaction temperature rise is much lower than that of ordinary cement grout,and the time of the temperature peak is significantly delayed.展开更多
文摘Inverse design of advanced materials represents a pivotal challenge in materials science.Leveraging the latent space of Variational Autoencoders(VAEs)for material optimization has emerged as a significant advancement in the field of material inverse design.However,VAEs are inherently prone to generating blurred images,posing challenges for precise inverse design and microstructure manufacturing.While increasing the dimensionality of the VAE latent space can mitigate reconstruction blurriness to some extent,it simultaneously imposes a substantial burden on target optimization due to an excessively high search space.To address these limitations,this study adopts a Variational Autoencoder guided Conditional Diffusion Generative Model(VAE-CDGM)framework integrated with Bayesian optimization to achieve the inverse design of composite materials with targeted mechanical properties.The VAE-CDGM model synergizes the strengths of VAEs and Denoising Diffusion Probabilistic Models(DDPM),enabling the generation of high-quality,sharp images while preserving a manipulable latent space.To accommodate varying dimensional requirements of the latent space,two optimization strategies are proposed.When the latent space dimensionality is excessively high,SHapley Additive exPlanations(SHAP)sensitivity analysis is employed to identify critical latent features for optimization within a reduced subspace.Conversely,direct optimization is performed in the low-dimensional latent space of VAE-CDGM when dimensionality is modest.The results demonstrate that both strategies accurately achieve the targeted design of composite materials while circumventing the blurred reconstruction flaws of VAEs,which offers a novel pathway for the precise design of advanced materials.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-KST-25-001)the Beijing Natural Science Foundation(No.L253029)。
文摘In the context of the global energy low-carbon transition,phase change energy storage technology becomes a key technology to solve the problem of intermittent renewable energy.Oriented phase change composites(OCPCMs)receive widespread attention in practical energy storage applications due to their unique oriented thermally conductive structure,which achieves significant thermal conductivity enhancement in specific directions while retaining the high energy storage capacity of the phase change components.This review systematically summarizes the overall analysis of OCPCMs from synthesis and preparation to application scenarios in recent years.Herein,we introduce the analysis of the heat transfer mechanism of the materials and explore the advantages of the oriented structure in OCPCMs in the heat transfer behavior from a bionic perspective.We then focus on summarizing and generalizing the methods for preparing OCPCMs,giving suggestions for suitable methods according to different scenarios.Besides,we discuss the application of finite element simulation methods to the monitoring of the thermal management behavior of OCPCMs,and look into the potential future application areas of such materials.Finally,it is hoped that this review will provide guidance for the academic community in developing high-performance OCPCMs.
基金supported by the National Science Foundation for Distinguished Young Scholars of China(No.52325506)the Fundamental Research Funds for the Central Universities(No.DUT22LAB501)。
文摘Ultrasonic-Assisted Grinding(UAG)is a novel manufacturing technology that shows promising promise for use in processing Ceramic Matrix Composites(CMCs).Nevertheless,analyzing the material removal process of CMCs with multidirectional structure during UAG is challenging,impeding the progress and improvement of the UAG process.This work examined the impact of ultrasonic vibration on the dynamic mechanical characteristics during processing.Additionally,we experimentally elucidated the material removal mechanism of CMCs during the scratching process under the influence of vertical vibration.The results indicate that the introduction of ultrasonic vibration causes a strain rate effect,resulting in a modification of the material removal mechanism,subsequently impacting the processing quality.Ultrasonic vibration increases the dynamic strength and brittleness of the fibers in CMCs,leading to more cracks at fracture,which changes from the original bending fracture to shear fracture.In addition,ultrasonic vibration can effectively inhibit the impact of scratching depth and anisotropy on the removal mechanism of CMCs,resulting in a more uniform surface of CMCs after processing.
基金supported by the National Natural Science Foundation of China(No.52127816),the National Key Research and Development Program of China(No.2020YFA0715000)the National Natural Science and Hong Kong Research Grant Council Joint Research Funding Project of China(No.5181101182)the NSFC/RGC Joint Research Scheme sponsored by the Research Grants Council of Hong Kong and the National Natural Science Foundation of China(No.N_PolyU513/18).
文摘Latent heat thermal energy storage(TES)effectively reduces the mismatch between energy supply and demand of renewable energy sources by the utilization of phase change materials(PCMs).However,the low thermal conductivity and poor shape stability are the main drawbacks in realizing the large-scale application of PCMs.Promisingly,developing composite PCM(CPCM)based on porous supporting mate-rial provides a desirable solution to obtain performance-enhanced PCMs with improved effective thermal conductivity and shape stability.Among all the porous matrixes as supports for PCM,three-dimensional carbon-based porous supporting material has attracted considerable attention ascribing to its high ther-mal conductivity,desirable loading capacity of PCMs,and excellent chemical compatibility with various PCMs.Therefore,this work systemically reviews the CPCMs with three-dimensional carbon-based porous supporting materials.First,a concise rule for the fabrication of CPCMs is illustrated in detail.Next,the experimental and computational research of carbon nanotube-based support,graphene-based support,graphite-based support and amorphous carbon-based support are reviewed.Then,the applications of the shape-stabilized CPCMs including thermal management and thermal conversion are illustrated.Last but not least,the challenges and prospects of the CPCMs are discussed.To conclude,introducing carbon-based porous materials can solve the liquid leakage issue and essentially improve the thermal conductivity of PCMs.However,there is still a long way to further develop a desirable CPCM with higher latent heat capacity,higher thermal conductivity,and more excellent shape stability.
文摘Composites made from biopolymers and natural fibers are gaining popularity as alternative sustainable structural materials.Biopolyesters including polylactic acid(PLA),polybutylene succinate(PBS),and polyhydroxyalkanoate(PHA),when mixed with natural fibers such as kenaf,hemp,and jute,provide an environmentally acceptable alternative to traditional fossil-based materials.This article examines current research on developments in the integration of biopolymers with natural fibers,with a focus on enhancing mechanical,thermal,and sustainability.Innovative approaches to surface treatment of natural fibers,such as biological and chemical treatments,have demonstrated enhanced adhesion with biopolymer matrices,increasing attributes such as tensile strength and rigidity.Furthermore,nano filling technologies such as nanocellulose and nanoparticles have improved the attributes of multifunctional composites,including heat conductivity and moisture resistance.According to performance analysis,biopolymernatural fiber-based composites may compete with synthetic composites in construction applications,particularly in lightweight buildings and automobiles.However,significant issues such as degradation in humid settings and longtermendurancemust be solved.To support a circular economy,solutions involve the development ofmoisture-resistant polymers and composite recycling technology.This article examines current advancements and identifies problems and opportunities to provide insight into the future direction of more inventive and sustainable biocomposites,and also the dangers they pose to green technology and industrial materials.These findings are significant in terms of the development of building materials which are not only competitive but also contribute to global sustainability.
基金funding support from the National Natural Science Foundation of China(No.52101046)Shuangjie Chu appreciates the funding support from the National Key Research and Development Program of China(No.2022YFB3705600).
文摘Iron-based metal matrix composites(IMMCs)have attracted significant research attention due to their high specific stiffness and strength,making them potentially suitable for various engineering applications.Microstructural design,including the selection of reinforcement and matrix phases,the reinforcement volume fraction,and the interface issues are essential factors determining the engineering performance of IMMCs.A variety of fabrication methods have been developed to manufacture IMMCs in recent years.This paper reviews the recent advances and development of IMMCs with particular focus on microstructure design,fabrication methods,and their engineering performance.The microstructure design issues of IMMC are firstly discussed,including the reinforcement and matrix phase selection criteria,interface geometry and characteristics,and the bonding mechanism.The fabrication methods,including liquid state,solid state,and gas-mixing processing are comprehensively reviewed and compared.The engineering performance of IMMCs in terms of elastic modulus,hardness and wear resistance,tensile and fracture behavior is reviewed.Finally,the current challenges of the IMMCs are highlighted,followed by the discussion and outlook of the future research directions of IMMCs.
基金financial support from National Natural Science Foundation of China(No.21908085)Natural Science Foundation of Jiangsu Province(No.BK20241950)+3 种基金China Postdoctoral Science Foundation(No.2023M731422)Open Project of State Key Laboratory of Materials Chemical Engineering(No.KL-NICE-23B03)Hubei Key Laboratory of Processing and Application of Catalytic Materials(No.202441204)the Science and Technology Plan School-Enterprise Cooperation IndustryUniversity-Research Forward-looking Project of Zhangjiagang(No.ZKYY2341)。
文摘Untreated water environments encourage the emergence of pathogenic microorganisms,which pose a significant risk to human health and sustainable development.Antimicrobial technologies in advanced photothermal materials offer a promising alternative strategy for solving water disinfection challenges.This technology effectively destroys bacterial biofilms by designing materials with controlled photothermal properties.Despite the potential of this technology,there is a lack of comprehensive reviews on the application of photothermal materials in water disinfection.The aim of this paper is to provide a comprehensive and up-to-date overview of the research and application of photothermal materials in water disinfection.It focuses on composites in photothermal materials,elucidates their basic mechanisms and sterilization properties,and provides a systematic and detailed overview of their recent progress in the field.The goal of this review is to offer insights into the future design of photothermal materials and to propose strategies for their practical application in disinfection processes.
基金supported by the National Natural Science Foundation of China(22302110,22375047,22378068)National Key Research and Development Program of China(2022YFB3804905)+1 种基金the Open Project Foundation of Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University(No.KJS2210)High-level Talent Initiative Project at Anhui Agricultural University(rc362401)。
文摘Flexible electronic skin(E-skin)sensors offer innovative solutions for detecting human body signals,enabling human-machine interactions and advancing the development of intelligent robotics.Electrospun nanofibers are particularly wellsuited for E-skin applications due to their exceptional mechanical properties,tunable breathability,and lightweight nature.Nanofiber-based composite materials consist of three-dimensional structures that integrate one-dimensional polymer nanofibers with other functional materials,enabling efficient signal conversion and positioning them as an ideal platform for next-generation intelligent electronics.Here,this review begins with an overview of electrospinning technology,including far-field electrospinning,near-field electrospinning,and melt electrospinning.It also discusses the diverse morphologies of electrospun nanofibers,such as core-shell,porous,hollow,bead,Janus,and ribbon structure,as well as strategies for incorporating functional materials to enhance nanofiber performance.Following this,the article provides a detailed introduction to electrospun nanofiber-based composite materials(i.e.,nanofiber/hydrogel,nanofiber/aerogel,nanofiber/metal),emphasizing their recent advancements in monitoring physical,physiological,body fluid,and multi-signal in human signal detection.Meanwhile,the review explores the development of multimodal sensors capable of responding to diverse stimuli,focusing on innovative strategies for decoupling multiple signals and their state-of-the-art advancements.Finally,current challenges are analyzed,while future prospects for electrospun nanofiber-based composite sensors are outlined.This review aims to advance the design and application of next-generation flexible electronics,fostering breakthroughs in multifunctional sensing and health monitoring technologies.
基金Key Project of Xizang Natural Science Foundation(Project No.:XZ202201ZR0053G)2023 Teaching Reform Project of Inner Mongolia Medical University(Project No.:NYJXGG2023025)“14th Five-Year Plan”Project of Educational Science Research in Inner Mongolia Autonomous Region(Project No.:NGJGH2021278)。
文摘This paper reviews the research status and development trends of lattice-foam composite structural materials.It introduces the characteristics and applications of lattice metallic materials and metallic foam materials among ultra-light porous materials,and points out their respective shortcomings.Subsequently,it elaborates on the research progress of lattice-foam composite structural materials at home and abroad,including the research achievements of research teams such as Xi’an Jiaotong University and the University of Virginia in the United States.Then,the key technologies in the preparation process of lattice-foam composite structural materials are discussed in detail,such as the rapid prototyping technology for special-shaped parts of porous materials,the friction stir welding technology for metallic foams,and the large-area joining and composite technology between the core and face sheets of composite structures.Finally,the research on lattice-foam composite structural materials is summarized and prospected.
基金support from the National Natural Science Foundation of China(52376216,52006194,52006191)the Key Research and Development Program of Shaanxi(2023-YBGY-054).
文摘Sodium ion batteries(SIBs)are one of the most prospective energy storage devices recently.Carbon materials have been commonly used as anode materials for SIBs because of their wide sources and low price.However,pure carbon materials still have the disadvantage of low theoretical capacity.New design and preparation strategies for carbon-based composites can overcome the problems.Based on the analysis of Na^(+)storage mechanism of carbon-based composite materials,the factors influencing the performance of SIBs are discussed.Adjustment methods for improving the electrochemical performance of electrodes are evaluated in detail,including carbon skeleton design and composite material selection.Some advanced composite materials,i.e.,carbon-conversion composite and carbon-MXene composite,are also being explored.New advances in flexible electrodes based on carbon-based composite on flexible SIBs is investigated.The existing issues and future issues of carbon-based composite materials are discussed.
基金supported by the National Key R&D Program(Grant No.2022YFA1203-100)sponsorship by Shanghai Sailing Program(Grant No.24YF2713800)+2 种基金financial support from the Local College Capacity Building Project of Shanghai Municipal Science and Technology Commission(Grant No.20010500700)the Natural Science Foundation of Shanghai(Grant No.23ZR1424300)Shanghai Shuguang Program(Grant No.22SG56)。
文摘In integrated circuit packaging,thermal interface materials(TIMs)must exhibit high thermal conductivity and electrical resistivity to prevent short circuits,enhance reliability,and ensure safety in high-voltage applications.We proposed the thermal-percolation electrical-resistive TIM incorporating binary fillers of both insulating and metallic nanowires with an orientation in the insulating polymer matrix.High thermal conductivity can be achieved through thermal percolation,while electrical non-conductivity is preserved by carefully controlling the electrical percolation threshold through metallic nanowire orientation.The electrical conductivity of the composite can be further regulated by adjusting the orientation and aspect ratio of the metallic fillers.A thermal conductivity of 10 W·m^(-1)·K^(-1)is achieved,with electrical non-conductive behavior preserved.This approach offers a pathway to realizing“thermal-percolation electrical-resistive”in hybrid TIMs,providing a strategic framework for designing high-performance TIMs.
基金Funded by the Scientific Research Program of Jilin Provincial Science and Technology Development(No.20250203184SF)。
文摘A solid,fast-dissolving sodium silicate was used as an alkaline activator.Granulated blast furnace slag(GGBS),metakaolin(MK),and steel slag(SS)were used as the cementious components to prepare a ternary composite cementitious material known as alkali-activated steel slag composite cementitious material(ASCM)by the"one-step method".The impacts of cementitious components,alkali activator modulus,and Na_(2)O%on the mechanical strength were investigated,and the hydration products and hydration kinetics of ASCM were analyzed.The experimental results reveal that XRD,FTIR,SEM,EDS,and exothermic heat of hydration show that when GGBS:MK:SS=60wt%:10wt%:30wt%,the activator modulus is 1.2,and the alkali content is 5.5wt%,the 28 d flexural strength of ASCM mortar is 12.6 MPa,and the compressive strength is 53.3 MPa,the hydration products consist of C-S-H gel/C-A-S-H gel,mullite(3Al_(2)O_(3)-2SiO_(2)),calcite(CaCO_(3)),quartz,etc.ASCM has a large initial hydration exotherm rate but a small cumulative exotherm.
基金Project(2011CB605801)supported by the National Basic Research Program of ChinaProject(2011M500127)supported by the China Postdoctoral Science Foundation+2 种基金Projects(51102089,50802115)supported by the National Natural Science Foundation of ChinaProjects(12JJ4046,12JJ9014)supported by the Natural Science Foundation of Hunan Province,ChinaProject(74341015817)supported by the Post-doctoral Fund of Central South University,China
文摘Silicon carbide/pyrolytic carbon (SiC/PyC) composite materials with excellent performance of self-lubrication and wear resistance were prepared on SiC substrates by electromagnetic-field-assisted chemical vapor infiltration (CVI). The composition and microstructure of the SiC/PyC materials were investigated in detail by XRD, SEM and EDS, etc. The effects of the deposition temperature on the section features and wear resistance of the SiC/PyC were studied. The results show that the PyC layers were deposited onto SiC substrates spontaneously at a lower deposition temperature. The SiC substrates deposited with PyC can significantly reduce the wear rate of the self-dual composite materials under dry sliding condition. The wear tests suggest that the SiC/PyC composite materials own a better wear resistance property when the deposition temperature is 800 °C, and the wear rate is about 64.6% of that without the deposition of PyC.
基金Projects(51004056,51004057)supported by the National Natural Science Foundation of ChinaProject(KKZ6201152009)supported by the Opening Foundation of Key Laboratory of Inorganic Coating Materials,Chinese Academy of Sciences+2 种基金Project(2010ZC052)supported by the Applied Basic Research Foundation of Yunnan Province,ChinaProject(20125314110011)supported by the Specialized Research Fund for the Doctoral Program of Higher Education,ChinaProject(2010247)supported by Analysis&Testing Foundation of Kunming University of Science and Technology,China
文摘Al/conductive coating/α-Pb O2-Ce O2-Ti O2/β-PbO 2-MnO 2-WC-Zr O2 composite electrode material was prepared on Al/conductive coating/α-PbO 2-Ce O2-Ti O2 substrate by electrochemical oxidation co-deposition technique. The effects of current density on the chemical composition, electrocatalytic activity, and stability of the composite anode material were investigated by energy dispersive X-ray spectroscopy（EDXS）, anode polarization curves, quasi-stationary polarization（Tafel） curves, electrochemical impedance spectroscopy（EIS）, scanning electron microscopy（SEM）, and X-ray diffraction（XRD）. Results reveal that the composite electrode obtained at 1 A/dm2 possesses the lowest overpotential（0.610 V at 500 A/m2） for oxygen evolution, the best electrocatalytic activity, the longest service life（360 h at 40 °C in 150 g/L H2SO4 solution under 2 A/cm2）, and the lowest cell voltage（2.75 V at 500 A/m2）. Furthermore, with increasing current density, the coating exhibits grain growth and the decrease of content of Mn O2. Only a slight effect on crystalline structure is observed.
基金Supported by the Autonomous Research Project of SKLCC(2024BWZ003)Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0390401)the Doctoral Research Start-up Funding of Shanxi Institute of Technology(026012).
文摘KIT-5/Beta composite supports were synthesized using an in situ self-assembly hydrothermal method,and NiW/KIT-5/Beta catalysts were prepared by impregnation.A series of characterization techniques were utilized to evaluate the influence of varying hydrothermal synthesis temperatures on the physicochemical properties of both the KIT-5/Beta supports and the resulting catalysts.The catalytic performances of catalysts were evaluated under reaction conditions of 320℃,4 MPa H_(2)pressure,and a weight hourly space velocity(WHSV)of 4.8 h^(-1)for hydrodenitrogenation(HDN)of quinoline.The results indicated that the specific surface area and pore structure of the materials could be effectively regulated by adjusting the hydrothermal synthesis temperature,which in turn influenced the number of active sites on the catalyst.The NiW/KB-125 catalyst,synthesized at 125℃,presented the highest quinoline HDN efficiency(96.8%),which can be attributed to its favorable pore channel structure,greater Brønsted acid number,higher degree of metal sulfidation(80.12%)and appropriate metal-support interaction(MSI).
基金supported by the National Natural Science Foundation of China (NSFC 52175352)。
文摘Electroslag remelting(ESR) is an important metallurgical process for producing high-purity materials with homogeneous compositions and sound microstructures,and its typical products are ingots or simple castings.The core principle involves the resistive melting of a consumable electrode within a slag pool,followed by the refining of molten metal droplets as they traverse the slag,and subsequent sequential solidification in a water-cooled mold.However,conventional ESR processes face limitations in producing large or complex-shaped components,enhancing production efficiency,achieving highly specialized microstructures,and meeting ultra-high purity demands for advanced applications.Advanced composite ESR technologies have been developed to overcome these limitations by innovatively modifying key process aspects.For instance,electrode systems are improved using vibration,rotation,or multiple electrodes.Enhanced mold design and solidification control are achieved through techniques including conductive molds,mold rotation,and ingot withdrawal.Precise control of the process is realized through the use of protective gas,vacuum,or elevated pressure,as well as the application of external fields such as magnetic fields or ultrasonic vibration.This review comprehensively summarizes these advanced techniques,examining their principles and characteristics,and discussing their specific advantages and challenges.
文摘Typically used thermal insulation materials such as foam insulation and fibreglass may pose notable health risks and environmental impacts thereby resulting in respiratory irritation andwaste disposal issues,respectively.While these materials are affordable and display good thermal insulation,their unsustainable traits pertaining to an intensive manufacturing process and poor disposability are major concerns.Alternative insulation materials with enhanced sustainable characteristics are therefore being explored,and one type of material which has gained notable attention owing to its low carbon footprint and low thermal conductivity is natural fibre.Among the few review studies conducted on Natural Fibre Reinforced Composite(NFRC)insulation boards,the multitude of factors and underlying mechanisms affecting their thermal conductivity performance have been sparsely covered.This review study aimed to address this gap by providing a holistic overview of some of the key intrinsic and extrinsic factors affecting the thermal conductivity performance of NFRCs.Key intrinsic factors pertaining to the microstructural features and to the physico-mechanical traits of NFRCs,namely the fibre lumen size,α,and the fibre-matrix thermal conductivity ratio,β,respectively,were found to largely affect the Transverse Thermal Conductivity(TTC)in NFRC boards.Extrinsic factors,which were found to indirectly affect NFRCs’thermal conductivity,such as fibre pre-processing,composite manufacturing and environmental factors,were also covered.Some of the noteworthy NFRC featureswhich were found to affect their thermal conductivity are volume fraction of fibres,bulk density and porosity.The findings of this study highlight the need for additional research investigation to address the foregoing limitations observed in NFRC thermal insulation boards by considering appropriate natural fibres,composition and fabrication techniques.The fabrication of high-grade NFRC boards,which will display an optimum balance between enhanced thermal insulation and long-term durability performance,could further replace conventionally used thermal insulation boards in the modern building and construction industry.
基金financial support granted by the National Natural Science Foundation of China (No. 22402225)the Gusu Innovation and Entrepreneurship Leading Talent Plan(No. ZXL2023193)+2 种基金the Sinano Talents Plan (No. 2022000175)the Guangdong Basic and Applied Basic Research Foundation (No.2023A1515111133)the ANSO Scholarship for Young Talents
文摘Inorganic materials can solve transportable and on-site hydrolytic hydrogen generation issues.CaH_(2)/(Al/Si)composites are preferable due to their notable chemical properties.However,these composites require pretreatments,an inert environment,and long hours of physical ball milling for high homogeneity and synergistic effects.CaH_(2)also inhibits the hydrolysis reaction by forming its products on the Al/Si surface,which hinders the direct utilization of composites.This work represents the first investigation of NaH-CaH_(2)(Al/Si)fuel composites,which greatly overcome these limitations and can be directly used for on-site hydrogen generation and proton exchange membrane(PEM)fuel cells.The NaH-CaH_(2)(Al/Si)fuel composites were prepared by using a straightforward mixing method with variable composition ratios,showing high H_(2)yield and fuel cell(FC)performance.NaH addition provides the bridge effect,which opens up a new way to enable efficient hydrolysis and greatly enhances the hydrolysis activity of CaH_(2)/(Al/Si)composites.The novel fuel composites(NaH-CaH_(2)/Al)have extraordinary FC performance and a 0.42 W/cm2 peak power density greater than commercial hydrogen generators.It provides high H_(2)yield 84.4%for NaH-CaH_(2)/Al and 82%for NaH-CaH_(2)/Si compared to NaOH-CaH_(2)(Al/Si),NaCl-CaH_(2)(Al/Si),and KCl-CaH_(2)(Al/Si)composites.The NaH bridge effect hinders the direct water contact and stops the formation of Ca(OH)2 around Al/Si,which provides adequate pathways for the CaH_(2)(Al/Si)hydrolysis.The impressive capabilities of novel fuel composites are anticipated to offer practical uses in fuel cells,automobile applications,and portable/on-board H_(2)generation.
基金support by the National Key R&D Program of China(Grant No.2023YFA1008901)the National Natural Science Foundation of China(Grant Nos.11988102,12172009)is gratefully acknowledged.
文摘In this manuscript,we propose an analytical equivalent linear viscoelastic constitutive model for fiber-reinforced composites,bypassing general computational homogenization.The method is based on the reduced-order homogenization(ROH)approach.The ROH method typically involves solving multiple finite element problems under periodic conditions to evaluate elastic strain and eigenstrain influence functions in an‘off-line’stage,which offers substantial cost savings compared to direct computational homogenization methods.Due to the unique structure of the fibrous unit cell,“off-line”stage calculation can be eliminated by influence functions obtained analytically.Introducing the standard solid model to the ROH method enables the creation of a comprehensive analytical homogeneous viscoelastic constitutive model.This method treats fibrous composite materials as homogeneous,anisotropic viscoelastic materials,significantly reducing computational time due to its analytical nature.This approach also enables precise determination of a homogenized anisotropic relaxation modulus and accurate capture of various viscoelastic responses under different loading conditions.Three sets of numerical examples,including unit cell tests,three-point beam bending tests,and torsion tests,are given to demonstrate the predictive performance of the homogenized viscoelastic model.Furthermore,the model is validated against experimental measurements,confirming its accuracy and reliability.
文摘In order to adjust some properties of cement grout or concrete,some mineral admixtures are usually added in the preparation.Admixtures can reduce the cement consumption and save the cost,and also adjust the workability of the material,improve the strength and durability of the cement stone,or reduce hydration heat of the composite cement.At present,the content of fly ash or slag is generally less than 50%among the composite cementitious materials that have been studied more,but there is little research on composite cementitious materials with large mineral admixture.In this paper,XRD,SEM,and adiabatic temperature rise tests were used to discuss hydration products and mechanism of composite cement grout with 90%content of fly ash and slag.The results show that the hydration of the composite cement grout is an alkali-activated hydration reaction,and the hydration products are mainly amorphous substances such as hydrated calcium silicate or hydrated calcium aluminate gel.The hydration reaction temperature rise is much lower than that of ordinary cement grout,and the time of the temperature peak is significantly delayed.
