The silicification of rice straw is a factor that affects the grain production and straw nutritive quality. The procedure of chemical analysis for silicon in straw is, however, time and labor consuming, and slightly p...The silicification of rice straw is a factor that affects the grain production and straw nutritive quality. The procedure of chemical analysis for silicon in straw is, however, time and labor consuming, and slightly poor in accuracy. The study has attempted to apply near infrared reflectance spectroscopy (NIRS) technique as an advanced alternative to predict the fiber composition and silicification in rice straw. Ninety-two samples from different seasons and varieties were collected over the Fujian Province. Their chemical analyses were carried on the aspects of hemicellulose, cellulose, lignin, extractable and non-extractable silicon, and the results were used as a database for NIRS analyses. The prediction model was developed through modified partial least square regression (MPLS) for a calibration program. The factors that may affect the calibration, cross-validation and the prediction for the application of NIRS on rice straw were also discussed.展开更多
Variable stiffness composites present a promising solution for mitigating impact loads via varying the fiber volume fraction layer-wise,thereby adjusting the panel's stiffness.Since each layer of the composite may...Variable stiffness composites present a promising solution for mitigating impact loads via varying the fiber volume fraction layer-wise,thereby adjusting the panel's stiffness.Since each layer of the composite may be affected by a different failure mode,the optimal fiber volume fraction to suppress damage initiation and evolution is different across the layers.This research examines how re-allocating the fibers layer-wise enhances the composites'impact resistance.In this study,constant stiffness panels with the same fiber volume fraction throughout the layers are compared to variable stiffness ones by varying volume fraction layer-wise.A method is established that utilizes numerical analysis coupled with optimization techniques to determine the optimal fiber volume fraction in both scenarios.Three different reinforcement fibers(Kevlar,carbon,and glass)embedded in epoxy resin were studied.Panels were manufactured and tested under various loading conditions to validate results.Kevlar reinforcement revealed the highest tensile toughness,followed by carbon and then glass fibers.Varying reinforcement volume fraction significantly influences failure modes.Higher fractions lead to matrix cracking and debonding,while lower fractions result in more fiber breakage.The optimal volume fraction for maximizing fiber breakage energy is around 45%,whereas it is about 90%for matrix cracking and debonding.A drop tower test was used to examine the composite structure's behavior under lowvelocity impact,confirming the superiority of Kevlar-reinforced composites with variable stiffness.Conversely,glass-reinforced composites with constant stiffness revealed the lowest performance with the highest deflection.Across all reinforcement materials,the variable stiffness structure consistently outperformed its constant stiffness counterpart.展开更多
To assess the effects of a time-restricted feeding(TRF)regimen on meat quality of pigs exposed to high ambient temperature,a two-month feeding and heat treatment(HT)trial was conducted using a 2×2 factorial desig...To assess the effects of a time-restricted feeding(TRF)regimen on meat quality of pigs exposed to high ambient temperature,a two-month feeding and heat treatment(HT)trial was conducted using a 2×2 factorial design.A total of 24 growing pigs(11.0±1.9 kg)were randomly divided into four groups:thermal neutral group(NT,24±3°C),HT group(exposed to a high temperature at 35±2°C from 11:00 to 15:00),TRF group and HT+TRF group(HT and TRF co-treatment group,n=6 for each group).Pigs in TRF groups got access to feed within 5 h from 9:00 to14:00,while the others were fed at 6:00,11:30,and 16:00.All pigs received the same diet during the trail.The results showed that HT increased the drip loss,shear force,lightness,and malondialdehyde production in Longissimus thoracis et lumborum(LTL)muscle.TRF reversely reduced the shear force and drip loss,accompanied by decreased intramuscular fat and increased moisture content.Enhanced fiber transformation from type 1 to type 2b and down-regulated expression of muscle growth-related genes were observed by HT,while TRF suppressed the fiber transformation and expression of muscle atrophy-related genes.Furthermore,TRF restored the diminished protein expressions of Nrf2 and HO-1 in LTL muscle by chronic HT.Accumulation of HSP70 in muscle of HT group was reduced by treatment of TRF.HT declined the expression of vital genes involved in fatty acids poly-desaturation and the proportion of(polyunsaturated fatty acids)PUFAs,mainly omega-6 in LTL muscle,while TRF group promoted the expression of poly-desaturation pathway and displayed the highest proportion of PUFAs.These results demonstrated that TRF relieved the chronic high temperature affected meat quality by the restored expression of Nrf2/HO-1 anti-oxidative cascade,modified muscle fiber composition,and enriched PUFAs in LTL muscle.展开更多
Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are kn...Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are known for their unique compact structure;they are not only lightweight but also strong.In this study,an in-depth look at owl feathers was made and it found that owl feathers not only have the macro branches structure between feather shafts and branches but also have fine feather structures on the branches.The presence of these fine feather structures increases the specific surface area of the plume branches and allows neighboring plume branches to hook up with each other,forming an effective mechanical interlocking structure.These structures bring owl feathers excellent mechanical properties.Inspired by the natural structure of owl feathers,a weaving technique and a sizing process were combined to prepare bionic Carbon Fiber(CF)fabrics and then to fabricate the bionic CFRP with structural characteristics similar to owl feathers.To evaluate the effect of the fine feather structure on the mechanical properties of CFRP,a mechanical property study on CFRP with and without the fine feather imitation structure were conducted.The experimental results show that the introduction of the fine feather branch structure enhance the mechanical properties of CFRP significantly.Specifically,the tensile strength of the composites increased by 6.42%and 13.06%and the flexural strength increased by 8.02%and 16.87%in the 0°and 90°sample directions,respectively.These results provide a new design idea for the improvement of the mechanical properties of the CFRP,promoting the application of CFRP in engineering fields,such as automotive transportation,rail transit,aerospace,and construction.展开更多
A Shape Memory Polymer Composite(SMPC)is developed by reinforcing an epoxy-based polymer with randomly oriented short glass fibers.Diverging from previous research,which primarily focused on the hot programming of sho...A Shape Memory Polymer Composite(SMPC)is developed by reinforcing an epoxy-based polymer with randomly oriented short glass fibers.Diverging from previous research,which primarily focused on the hot programming of short glass fiber-based SMPCs,this work explores the potential for programming below the glass transition temperature(Tg)for epoxy-based SMPCs.To mitigate the inherent brittleness of the SMPC during deformation,a linear polymer is incorporated,and a temperature between room temperature and Tg is chosen as the deformation temperature to study the shape memory properties.The findings demonstrate an enhancement in shape fixity and recovery stress,alongside a reduction in shape recovery,with the incorporation of short glass fibers.In addition to tensile properties,thermal properties such as thermal conductivity,specific heat capacity,and glass transition temperature are investigated for their dependence on fiber content.Microscopic properties,such as fiber-matrix adhesion and the dispersion of glass fibers,are examined through Scanning Electron Microscope imaging.The fiber length distribution and mean fiber lengths are also measured for different fiber fractions.展开更多
The automobile industry is the first to form a typical representative of the global industry in modern industry,with the increase of the national emphasis on the environment,the automobile industry was regarded as an ...The automobile industry is the first to form a typical representative of the global industry in modern industry,with the increase of the national emphasis on the environment,the automobile industry was regarded as an important energy consumption and one of the sources of environmental pollution,the policy of energy conservation and emission reduction requirements for the automobile industry are becoming stricter over the years,energy conservation and emission reduction has becomes the main direction of product optimization in the automobile industry in recent years.Due of a series of excellent properties such as light weight and high strength,composite materials have become the main material for the development of lightweight vehicles.With the development of material technology and the update and iteration of manufacturing technology,composite materials are currently popular being adopted in the automotive field.展开更多
Embedding optical fiber sensors into composite materials offers the advantage of real-time structural monitoring.However,there is an order-of-magnitude difference in diameter between optical fibers and reinforcing fib...Embedding optical fiber sensors into composite materials offers the advantage of real-time structural monitoring.However,there is an order-of-magnitude difference in diameter between optical fibers and reinforcing fibers,and the detailed mechanism of how embedded optical fibers affect the micromechanical behavior and damage failure processes within composite materials remains unclear.This paper presents a micromechanical simulation analysis of composite materials embedded with optical fibers.By constructing representative volume elements(RVEs)with randomly distributed reinforcing fibers,the optical fiber,the matrix,and the interface phase,the micromechanical behavior and damage evolution under transverse tensile and compressive loads are explored.The study finds that the presence of embedded optical fibers significantly influences the initiation and propagation of microscopic damage within the composites.Under transverse tension,the fiber-matrix interface cracks first,followed by plastic cracking in the matrix surrounding the fibers,forming micro-cracks.Eventually,these cracks connect with the debonded areas at the fiber-matrix interface to form a dominant crack that spans the entire model.Under transverse compression,plastic cracking first occurs in the resin surrounding the optical fibers,connecting with the interface debonding areas between the optical fibers and the matrix to form two parallel shear bands.Additionally,it is observed that the strength of the interface between the optical fiber and the matrix critically affects the simulation results.The simulated damage morphologies align closely with those observed using scanning electron microscopy(SEM).These findings offer theoretical insights that can inform the design and fabrication of smart composite materials with embedded optical fiber sensors for advanced structural health monitoring.展开更多
This research explores the water uptake behavior of glass fiber/epoxy composites filled with nanoclay and establishes an Artificial Neural Network(ANN)to predict water uptake percentage fromexperimental parameters.Com...This research explores the water uptake behavior of glass fiber/epoxy composites filled with nanoclay and establishes an Artificial Neural Network(ANN)to predict water uptake percentage fromexperimental parameters.Composite laminates are fabricated with varying glass fiber(40-60 wt.%)and nanoclay(0-4 wt.%)contents.Water absorption is evaluated for 70 days of immersion following ASTM D570-98 standards.The inclusion of nanoclay reduces water uptake by creating a tortuous path for moisture diffusion due to its high aspect ratio and platelet morphology,thereby enhancing the composite’s barrier properties.The ANN model is developed with a 3-4-1 feedforward structure and learned through the Levenberg-Marquardt algorithm with soaking time(7 to 70 days),fiber content(40,50,and 60 wt.%)and nanoclay content(0,2,and 4 wt.%)as input parameters.The model’s output is the water uptake percentage.The model has high prediction efficiency,with a correlation coefficient(R)of 0.998 and a mean squared error of 1.38×10^(-4).Experimental and predicted values are in excellent agreement,ensuring the reliability of the ANN for the simulation of nonlinear water absorption behavior.The results identify the synergistic capability of nanoclay and fiber concentration to reduce water absorption and prove the feasibility of ANN as a substitute for time-consuming testing in composite durability estimation.展开更多
3D printing has emerged as an advanced manufacturing technique for carbon fiber reinforced composites and relevant structures that endure significant dynamic loads in engineering applications.The dynamic behavior of t...3D printing has emerged as an advanced manufacturing technique for carbon fiber reinforced composites and relevant structures that endure significant dynamic loads in engineering applications.The dynamic behavior of these materials,primarily influenced by the dynamic fiber pullout interface strength necessitates investigation into the rate-dependent fiber/matrix interfacial strength.This study modifies a Hopkinson tension bar to conduct dynamic pullout tests on a single fiber bundle,utilizing a low-impedance bar and an in-situ calibrated semiconductor strain gauge to capture weak stress signals.Stress equilibrium analyses are performed to validate the transient dynamic loading on single fiber bundle specimens.The results reveal that the fiber/matrix interfacial strength is rate-dependent,increasing with the loading rate,while remaining unaffected by the embedded length.Fracture microstructural analyses show minimal fiber pullout due to high interfacial stresses induced by longer embedded lengths.Lastly,suggestions are made for the efficient design of fiber pullout experiments.展开更多
Solar steam generation(SSG)offers a cost-effective solution for producing clean water by utilizing solar energy.However,integrating effective thermal management and water transportation to develop high-efficiency sola...Solar steam generation(SSG)offers a cost-effective solution for producing clean water by utilizing solar energy.However,integrating effective thermal management and water transportation to develop high-efficiency solar evaporators remains a significant challenge.Here,inspired by the hierarchical structure of the stem of bird of paradise,a three-dimensional multiscale liquid metal/polyacrylonitrile(LM/PAN)evaporator is fabricated by assembling LM/PAN fibers.The strong localized surface plasmon resonance of LM particles and porous structure of LM/PAN fibers with interconnected channels lead to efficient light absorption up to 90.9%.Consequently,the multiscale biomimetic LM/PAN evaporator achieves an outstanding water evaporation rate of 2.66 kg m^(-2)h^(-1)with a solar energy efficiency of 96.5%under one sun irradiation and an exceptional water rate of 2.58 kg m^(-2)h^(-1)in brine.Additionally,the LM/PAN evaporator demonstrates a superior purification performance for seawater,with the concentration of Na^(+),Mg^(2+),K^(+)and Ca^(2+)in real seawater dramatically decreased by three orders to less than 7 mg L^(-1) after desalination under light irradiation.The multiscale LM/PAN evaporator with hierarchical structure regulates the water transportation as well as thermal management for highly effective solar-driven evaporation,providing valuable insight into the structural design principles for advanced SSG systems.展开更多
Polymer fibers are an important class of materials throughout human history,evolving from natural fibers such as cotton and silk to modern synthetic fibers such as nylon and polyester.With the advancement of materials...Polymer fibers are an important class of materials throughout human history,evolving from natural fibers such as cotton and silk to modern synthetic fibers such as nylon and polyester.With the advancement of materials science,the development of new fibers is also advancing.Polymer fibers based on dynamic covalent chemistry have attracted widespread attention due to their unique reversibility and responsiveness.Dynamic covalent chemistry has shown great potential in improving the spinnability of materials,achieving green preparation of fibers,and introducing self-healing,recyclability,and intelligent response properties into fibers.In this review,we divide these fiber materials based on dynamic covalent chemistry into monocomponent fibers,composite fibers,and fiber membranes.The preparation methods,structural characteristics,functional properties,and application performance of these fibers are summarized.The application potential and challenges of fibers based on dynamic covalent chemistry are discussed,and their future development trends are prospected.展开更多
Owing to their high flexibility and directional actuation capabilities,macro fiber composites(MFCs)have attracted significant attention for the active control of structures,especially in the nonlinear vibration suppre...Owing to their high flexibility and directional actuation capabilities,macro fiber composites(MFCs)have attracted significant attention for the active control of structures,especially in the nonlinear vibration suppression applications for large-scale flexible structures.In this paper,an MFC-based self-feedback system is introduced for the active control of geometrically nonlinear steady-state forced vibrations in functionally graded carbon nanotube reinforced composite(FG-CNTRC)plates subject to transverse mechanical loads.Based on the first-order shear deformation theory and the von Kármán nonlinear strain-displacement relationship,the nonlinear vibration control equations of the plate with MFC sensor and actuator layers are derived by Hamilton's principle.These equations are discretized by the finite element method(FEM),and solved by the Newton-Raphson and direct iterative methods.A velocity feedback control algorithm is introduced,and the effects of the control gain and the MFC actuator position on the nonlinear vibration active control effectiveness are analyzed.Additionally,a nonlinear resonance analysis is carried out,considering the effects of carbon nanotube(CNT)volume fraction and distribution type.The results indicate that the intrinsic characteristics of the structures significantly influence the vibration behavior.Furthermore,the appropriate selections of control gain and MFC position are crucial for the effective active control of the structures.The present work provides a promising route of the active and efficient nonlinear vibration suppression for various thin-walled structures.展开更多
The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the...The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the Two-Dimensional (2D) nanomaterials with unique lamellar structures and biological properties have been demonstrated to have excellent antibacterial properties. Antibacterial properties can be improved by feasible chemical strategies for preparing 2D nanomaterials coating on the surface of CFR-P. In this work, Black Phosphorus (BP) coating was prepared on the originally chemically inert CFR-P surface based on wet chemical pretreatment. The physical and chemical properties, including surface microstructure, chemical composition and state, roughness and hydrophilicity were characterized. The antibacterial ratios against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Streptococcus mutans (S. mutans) were evaluated. The results indicated that hydrophilicity of BP coating on CFR-P was significantly higher compared to that of the pure CFR-P. Wet chemical pretreatment using mixed acid reagents (concentrated sulfuric acid and concentrated nitric acid) introduced hydroxyl, carboxyl and nitro groups on CFR-P. The BP coating exhibited the antibacterial rate of over 98% against both S. aureus and E. coli. In addition, the antibacterial rate of BP coating against the main pathogenic bacteria of dental caries, Streptococcus mutans, reached 45%.展开更多
Polyether ether ketone(PEEK)-based continuous glass fiber reinforced thermoplastic composite offers advantages such as high strength,electrical insulation,and heat insulation.Parts manufactured using this composite an...Polyether ether ketone(PEEK)-based continuous glass fiber reinforced thermoplastic composite offers advantages such as high strength,electrical insulation,and heat insulation.Parts manufactured using this composite and 3D printing have promising applications in aerospace,automobile,rail transit,etc.In this paper,a high-temperature melt impregnation method was used to successfully prepare the 3D printing prepreg filaments of the aforementioned composite.In the FDM 3D printing equipment,a nozzle of high thermal conductivity and wear-resistant copper alloy and a PEEK-based carbon fiber thermoplastic composite build plate with uniform temperature control were innovatively introduced to effectively improve the quality of 3D printing.The porosity of the 3D printed samples produced from the composite prepreg filament was analyzed under different printing parameters,and the mechanical properties and fracture mechanism of the printed parts were studied.The results show that the printing layer thickness,printing speed,printing temperature and build plate temperature have varying effects on the porosity of printed parts,which in turn affects tensile strength and the interlaminar shear strength(ILSS).When the printing layer thickness is 0.4 mm,printing speed is 2 mm/s,nozzle temperature is 430℃ and build plate temperature is 150℃,the tensile strength and ILSS of the composite printed parts reach their maximum values of 463.76 and 24.95 MPa,respectively.Microscopic analysis of the fracture morphology of the tensile specimens reveals that the 3D printed CGF/PEEK composite sample has three types of fracture mode,which are single filament bundle fracture,fracture mode of delamination,and fracture failure of the sample at the cross-section.The essence of the above three kinds of fracture mode is the difference of the interface bonding force of 3D printed CGF/PEEK composites.The fracture failure at the cross-section is that the continuous glass fibers in the composite are pulled out until they break,which is the main form of the failure of the composite under tensile load.The interfacial region of the composite is prone to microscopic defects such as voids and delamination during 3D printing,which become the most vulnerable link of the composite.Understanding the relationship between voids and fracture behavior lays a foundation for defect suppression and performance improvement of subsequent printed parts.展开更多
Carbon fiber/phenolic resin composites have great potential application in the field of electronic information,where excellent structural-functional integration is required.In this work,the establishment of interfacia...Carbon fiber/phenolic resin composites have great potential application in the field of electronic information,where excellent structural-functional integration is required.In this work,the establishment of interfacial structures consisting of carbon nanotubes with different morphologies at the fiber/matrix interface is conducive to the further modulation of the mechanical,tribological,electromagnetic interference(EMI)shielding and thermal conductivity properties of carbon fiber/phenolic resin composites.Specially,array carbon nanotubes can deep into the resin matrix,effectively hindering crack extension,and constructing an electrically and thermally conductive network.Compared with the carbon fiber/phenolic composites,the tensile strength and modulus of elasticity(163.86±9.60 MPa,5.06±0.25 GPa)of the array carbon nanotubes reinforced carbon fiber/phenolic composites were enhanced by 57.09%and 22.22%.The average friction coefficient and wear rate(0.20±0.02,1.11×10^(-13)±0.13×10^(-13)m^(3)N^(−1)m^(−1))were reduced by 39.39%and 74.31%.EMI shielding effectiveness up to 40 dB in the X-band at 0.4 mm sample thickness,diffusion coefficient(0.39±0.003 mm^(2)/s)and thermal conductivity(0.54±0.004 W/(m K))were enhanced by up to 14.37%and 50.42%.This study reveals the beneficial effects of morphological changes of carbon nanotubes on the design of interfacial structure,proposes the reinforcement mechanism of array carbon nanotubes,and opens up the prospect of carbon fiber/phenolic composites for electronic applications.展开更多
Solar interfacial evaporation(SIE),is currently one of the most potential water supply technologies in the remote,insular,and disaster-stricken areas.However,the existence of volatile organic compounds(VOCs)in water d...Solar interfacial evaporation(SIE),is currently one of the most potential water supply technologies in the remote,insular,and disaster-stricken areas.However,the existence of volatile organic compounds(VOCs)in water deteriorates the distillate quality,threatening human health.Herein,we constructed a carbonbased bimetallic(C/FeCo)photothermal membrane by electrospinning technique.Results illustrated that the membrane can catalytically degrade VOCs during SIE with persulfate(PDS)mediation.PDS,as well as phenol,was mainly reacted on the interface of the photothermal membrane instead of in the bulk solution.The interception efficiency of phenol achieved nearly 100%using the C/FeCo membrane during SIE.Hydroxyl radical(•OH),sulfate radical(SO_(4)•−),superoxide radical(O_(2)•−),and singlet oxygen(^(1)O_(2))were identified as the main active substances to degrade VOCs.We also conducted SIE experiments using actual river water to evaluate the practical performance of the C/FeCo membrane.This work holds the promise of VOCs interception during SIE and enlarges the application of solar distillation in water/wastewater treatment.展开更多
Fiber reinforced ceramic matrix composites(FRCMCs)are the preferred materials for safety critical components in the fields of aerospace,nuclear engineering,and transportation,with broad market and application prospect...Fiber reinforced ceramic matrix composites(FRCMCs)are the preferred materials for safety critical components in the fields of aerospace,nuclear engineering,and transportation,with broad market and application prospects.However,due to the characteristics of multiphase,heterogeneity,and anisotropy,key issues such as poor adhesion,high porosity,and crack propagation urgently need to be addressed in the fabrication and machining of FRCMCs.With the increasing demand for FRCMCs parts,high-quality and reliable design and fabrication,performance evaluation,and precision manufacturing have become a series of hot issues.There is a lack of systematic review in capturing the current research status and development direction of FRCMCs fabrication and machining.This research aims to comprehensively review and critically evaluate the existing understanding of the fabrication and machining of FRCMCs.This study can provide scientists with a deeper understanding of the shape control mechanism of FRCMCs fabrication and machining,the theoretical basis of material synchronous removal,machining performance,and development direction.Firstly,the basic characteristics and application background of FRCMCs are introduced.Secondly,by comparing and analyzing the typical fabrication process of FRCMCs,the advantages,disadvantages,and performance evaluation of different processes are comprehensively evaluated.Thirdly,the material removal mechanisms and machining performance evaluation standards of traditional mechanical machining technologies(drilling,milling,grinding)and non-traditional mechanical machining technologies(ultrasonic,laser,water jet,discharge,wire saw,and multi-field hybrid machining)are discussed and analyzed.Finally,the challenges,development trends,and prospects faced by FRCMCs in the fields of fabrication,machining,and application are analyzed.This study not only elucidates the basic processes and key difficulties in the fabrication of FRCMCs,but also provides valuable insights for low-damage machining.展开更多
Piezoelectric materials are capable of actuation and sensing and have been used in a wide variety of smart devices and structures.Active fiber composite and macro fiber composite are newly developed types of piezoelec...Piezoelectric materials are capable of actuation and sensing and have been used in a wide variety of smart devices and structures.Active fiber composite and macro fiber composite are newly developed types of piezoelectric composites,and show superior properties to monolithic piezoelectric wafer due to their distinctive structures.Numerous work has focused on the performance prediction of the composites by evaluation of structural parameters and properties of the constituent materials with analytical and numerical methods.Various applications have been explored for the piezoelectric fiber composites,including vibration and noise control,health monitoring,morphing of structures and energy harvesting,in which the composites play key role and demonstrate the necessity for further development.展开更多
To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments...To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments on two typical stamping processes, thermal bending and thermal deep drawing, were conducted to investigate the forming behavior of composite sheets and analyze the influence of forming temperature on the formed composite part. Experimental results show that the locking angle for woven composite is about 30°. The bending load is smaller than 5 N in the stamping process and decreases with the increase of temperature. The optimal temperature to form the carbon fiber composite is 170 ℃. The die temperature distribution and the deformation of composite sheet were simulated by FEA software ABAQUS. To investigate the fiber movement of carbon woven fabric during stamping, the two-node three-dimension linear Truss unit T2D3 was chosen as the fiber element. The simulation results have a good agreement to the experimental results.展开更多
A cohesive zone model is employed to simulate the fiber/matrix interface damage of composites with ductile matrix. The study is carried out to investigate the dependence of the interface damage and the composite tensi...A cohesive zone model is employed to simulate the fiber/matrix interface damage of composites with ductile matrix. The study is carried out to investigate the dependence of the interface damage and the composite tensile strength on the micro parameters of the composite. These parameters contain fiber packing pattern, fiber volume fraction, and the modulus ratio of the fiber to the matrix. The investigation reveals that though the high fiber vo lume fraction, the high fiber′s modulus and the square fiber packing can supply strong reinforcement to the composite, the interface damage is susceptible in these cases. The tensile strength of the composite is dominated by the interface strength when the interface debonding occurs.展开更多
文摘The silicification of rice straw is a factor that affects the grain production and straw nutritive quality. The procedure of chemical analysis for silicon in straw is, however, time and labor consuming, and slightly poor in accuracy. The study has attempted to apply near infrared reflectance spectroscopy (NIRS) technique as an advanced alternative to predict the fiber composition and silicification in rice straw. Ninety-two samples from different seasons and varieties were collected over the Fujian Province. Their chemical analyses were carried on the aspects of hemicellulose, cellulose, lignin, extractable and non-extractable silicon, and the results were used as a database for NIRS analyses. The prediction model was developed through modified partial least square regression (MPLS) for a calibration program. The factors that may affect the calibration, cross-validation and the prediction for the application of NIRS on rice straw were also discussed.
基金funded by the American University of Sharjah.United Arab Emirates award number EN 9502-FRG19-M-E75。
文摘Variable stiffness composites present a promising solution for mitigating impact loads via varying the fiber volume fraction layer-wise,thereby adjusting the panel's stiffness.Since each layer of the composite may be affected by a different failure mode,the optimal fiber volume fraction to suppress damage initiation and evolution is different across the layers.This research examines how re-allocating the fibers layer-wise enhances the composites'impact resistance.In this study,constant stiffness panels with the same fiber volume fraction throughout the layers are compared to variable stiffness ones by varying volume fraction layer-wise.A method is established that utilizes numerical analysis coupled with optimization techniques to determine the optimal fiber volume fraction in both scenarios.Three different reinforcement fibers(Kevlar,carbon,and glass)embedded in epoxy resin were studied.Panels were manufactured and tested under various loading conditions to validate results.Kevlar reinforcement revealed the highest tensile toughness,followed by carbon and then glass fibers.Varying reinforcement volume fraction significantly influences failure modes.Higher fractions lead to matrix cracking and debonding,while lower fractions result in more fiber breakage.The optimal volume fraction for maximizing fiber breakage energy is around 45%,whereas it is about 90%for matrix cracking and debonding.A drop tower test was used to examine the composite structure's behavior under lowvelocity impact,confirming the superiority of Kevlar-reinforced composites with variable stiffness.Conversely,glass-reinforced composites with constant stiffness revealed the lowest performance with the highest deflection.Across all reinforcement materials,the variable stiffness structure consistently outperformed its constant stiffness counterpart.
基金supported by the Natural Science Foundation of Jiangsu Province(BK20220582)Jiangsu Funding Program for Excellent Postdoctoral Talent,the Jiangsu Agricultural Science And Technology Innovation Fund[CX(21)2014]+1 种基金Jiangsu Provincial Double-Innovation Team Program(JSSCTD202147)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘To assess the effects of a time-restricted feeding(TRF)regimen on meat quality of pigs exposed to high ambient temperature,a two-month feeding and heat treatment(HT)trial was conducted using a 2×2 factorial design.A total of 24 growing pigs(11.0±1.9 kg)were randomly divided into four groups:thermal neutral group(NT,24±3°C),HT group(exposed to a high temperature at 35±2°C from 11:00 to 15:00),TRF group and HT+TRF group(HT and TRF co-treatment group,n=6 for each group).Pigs in TRF groups got access to feed within 5 h from 9:00 to14:00,while the others were fed at 6:00,11:30,and 16:00.All pigs received the same diet during the trail.The results showed that HT increased the drip loss,shear force,lightness,and malondialdehyde production in Longissimus thoracis et lumborum(LTL)muscle.TRF reversely reduced the shear force and drip loss,accompanied by decreased intramuscular fat and increased moisture content.Enhanced fiber transformation from type 1 to type 2b and down-regulated expression of muscle growth-related genes were observed by HT,while TRF suppressed the fiber transformation and expression of muscle atrophy-related genes.Furthermore,TRF restored the diminished protein expressions of Nrf2 and HO-1 in LTL muscle by chronic HT.Accumulation of HSP70 in muscle of HT group was reduced by treatment of TRF.HT declined the expression of vital genes involved in fatty acids poly-desaturation and the proportion of(polyunsaturated fatty acids)PUFAs,mainly omega-6 in LTL muscle,while TRF group promoted the expression of poly-desaturation pathway and displayed the highest proportion of PUFAs.These results demonstrated that TRF relieved the chronic high temperature affected meat quality by the restored expression of Nrf2/HO-1 anti-oxidative cascade,modified muscle fiber composition,and enriched PUFAs in LTL muscle.
基金supported by the Science and Technology Development Program of Jilin Province(No.20240101122JC)and(No.20240101143JC)the Key Scientific and Technological Research and Development Projects of Jilin Provincial Science and Technology Department(Grant Number 20230201108GX)。
文摘Insufficient interfacial activity and poor wettability between fibers and matrix are the two main factors limiting the improvement of mechanical properties of Carbon Fiber Reinforced Plastics(CFRP).Owl feathers are known for their unique compact structure;they are not only lightweight but also strong.In this study,an in-depth look at owl feathers was made and it found that owl feathers not only have the macro branches structure between feather shafts and branches but also have fine feather structures on the branches.The presence of these fine feather structures increases the specific surface area of the plume branches and allows neighboring plume branches to hook up with each other,forming an effective mechanical interlocking structure.These structures bring owl feathers excellent mechanical properties.Inspired by the natural structure of owl feathers,a weaving technique and a sizing process were combined to prepare bionic Carbon Fiber(CF)fabrics and then to fabricate the bionic CFRP with structural characteristics similar to owl feathers.To evaluate the effect of the fine feather structure on the mechanical properties of CFRP,a mechanical property study on CFRP with and without the fine feather imitation structure were conducted.The experimental results show that the introduction of the fine feather branch structure enhance the mechanical properties of CFRP significantly.Specifically,the tensile strength of the composites increased by 6.42%and 13.06%and the flexural strength increased by 8.02%and 16.87%in the 0°and 90°sample directions,respectively.These results provide a new design idea for the improvement of the mechanical properties of the CFRP,promoting the application of CFRP in engineering fields,such as automotive transportation,rail transit,aerospace,and construction.
文摘A Shape Memory Polymer Composite(SMPC)is developed by reinforcing an epoxy-based polymer with randomly oriented short glass fibers.Diverging from previous research,which primarily focused on the hot programming of short glass fiber-based SMPCs,this work explores the potential for programming below the glass transition temperature(Tg)for epoxy-based SMPCs.To mitigate the inherent brittleness of the SMPC during deformation,a linear polymer is incorporated,and a temperature between room temperature and Tg is chosen as the deformation temperature to study the shape memory properties.The findings demonstrate an enhancement in shape fixity and recovery stress,alongside a reduction in shape recovery,with the incorporation of short glass fibers.In addition to tensile properties,thermal properties such as thermal conductivity,specific heat capacity,and glass transition temperature are investigated for their dependence on fiber content.Microscopic properties,such as fiber-matrix adhesion and the dispersion of glass fibers,are examined through Scanning Electron Microscope imaging.The fiber length distribution and mean fiber lengths are also measured for different fiber fractions.
文摘The automobile industry is the first to form a typical representative of the global industry in modern industry,with the increase of the national emphasis on the environment,the automobile industry was regarded as an important energy consumption and one of the sources of environmental pollution,the policy of energy conservation and emission reduction requirements for the automobile industry are becoming stricter over the years,energy conservation and emission reduction has becomes the main direction of product optimization in the automobile industry in recent years.Due of a series of excellent properties such as light weight and high strength,composite materials have become the main material for the development of lightweight vehicles.With the development of material technology and the update and iteration of manufacturing technology,composite materials are currently popular being adopted in the automotive field.
基金funded by the National Key Research and Development Program of China(Grant No.2022YFB3402500)the National Natural Science Foundation of China(Grant No.12372129).
文摘Embedding optical fiber sensors into composite materials offers the advantage of real-time structural monitoring.However,there is an order-of-magnitude difference in diameter between optical fibers and reinforcing fibers,and the detailed mechanism of how embedded optical fibers affect the micromechanical behavior and damage failure processes within composite materials remains unclear.This paper presents a micromechanical simulation analysis of composite materials embedded with optical fibers.By constructing representative volume elements(RVEs)with randomly distributed reinforcing fibers,the optical fiber,the matrix,and the interface phase,the micromechanical behavior and damage evolution under transverse tensile and compressive loads are explored.The study finds that the presence of embedded optical fibers significantly influences the initiation and propagation of microscopic damage within the composites.Under transverse tension,the fiber-matrix interface cracks first,followed by plastic cracking in the matrix surrounding the fibers,forming micro-cracks.Eventually,these cracks connect with the debonded areas at the fiber-matrix interface to form a dominant crack that spans the entire model.Under transverse compression,plastic cracking first occurs in the resin surrounding the optical fibers,connecting with the interface debonding areas between the optical fibers and the matrix to form two parallel shear bands.Additionally,it is observed that the strength of the interface between the optical fiber and the matrix critically affects the simulation results.The simulated damage morphologies align closely with those observed using scanning electron microscopy(SEM).These findings offer theoretical insights that can inform the design and fabrication of smart composite materials with embedded optical fiber sensors for advanced structural health monitoring.
文摘This research explores the water uptake behavior of glass fiber/epoxy composites filled with nanoclay and establishes an Artificial Neural Network(ANN)to predict water uptake percentage fromexperimental parameters.Composite laminates are fabricated with varying glass fiber(40-60 wt.%)and nanoclay(0-4 wt.%)contents.Water absorption is evaluated for 70 days of immersion following ASTM D570-98 standards.The inclusion of nanoclay reduces water uptake by creating a tortuous path for moisture diffusion due to its high aspect ratio and platelet morphology,thereby enhancing the composite’s barrier properties.The ANN model is developed with a 3-4-1 feedforward structure and learned through the Levenberg-Marquardt algorithm with soaking time(7 to 70 days),fiber content(40,50,and 60 wt.%)and nanoclay content(0,2,and 4 wt.%)as input parameters.The model’s output is the water uptake percentage.The model has high prediction efficiency,with a correlation coefficient(R)of 0.998 and a mean squared error of 1.38×10^(-4).Experimental and predicted values are in excellent agreement,ensuring the reliability of the ANN for the simulation of nonlinear water absorption behavior.The results identify the synergistic capability of nanoclay and fiber concentration to reduce water absorption and prove the feasibility of ANN as a substitute for time-consuming testing in composite durability estimation.
基金supported by the Key Research and Development Plan of Shaanxi Province(No.2023-GHZD-12)the Chinese Aeronautical Establishment Aeronautical Science Foundation(No.20230041053006)the National Natural Science Foundation of China(Nos.12472392 and 12172304).
文摘3D printing has emerged as an advanced manufacturing technique for carbon fiber reinforced composites and relevant structures that endure significant dynamic loads in engineering applications.The dynamic behavior of these materials,primarily influenced by the dynamic fiber pullout interface strength necessitates investigation into the rate-dependent fiber/matrix interfacial strength.This study modifies a Hopkinson tension bar to conduct dynamic pullout tests on a single fiber bundle,utilizing a low-impedance bar and an in-situ calibrated semiconductor strain gauge to capture weak stress signals.Stress equilibrium analyses are performed to validate the transient dynamic loading on single fiber bundle specimens.The results reveal that the fiber/matrix interfacial strength is rate-dependent,increasing with the loading rate,while remaining unaffected by the embedded length.Fracture microstructural analyses show minimal fiber pullout due to high interfacial stresses induced by longer embedded lengths.Lastly,suggestions are made for the efficient design of fiber pullout experiments.
基金supported by the National Natural Science Foundation of China(52372096,52102368,22205189,52203103)the Program for Guangdong Introducing Innovative and Entrepreneurial Teams(2017ZT07C291)+4 种基金the Shenzhen Science and Technology Program(JCYJ20230807114205011 and KQTD20170810141424366)the Guang Dong Basic and Applied Basic Research Foundation(2024A1515011953,2022A1515011010 and 2021A1515110350)the Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905)the Shenzhen Natural Science Foundation(GXWD20201231105722002-20200824163747001)the 2023 SZSTI stable support scheme.
文摘Solar steam generation(SSG)offers a cost-effective solution for producing clean water by utilizing solar energy.However,integrating effective thermal management and water transportation to develop high-efficiency solar evaporators remains a significant challenge.Here,inspired by the hierarchical structure of the stem of bird of paradise,a three-dimensional multiscale liquid metal/polyacrylonitrile(LM/PAN)evaporator is fabricated by assembling LM/PAN fibers.The strong localized surface plasmon resonance of LM particles and porous structure of LM/PAN fibers with interconnected channels lead to efficient light absorption up to 90.9%.Consequently,the multiscale biomimetic LM/PAN evaporator achieves an outstanding water evaporation rate of 2.66 kg m^(-2)h^(-1)with a solar energy efficiency of 96.5%under one sun irradiation and an exceptional water rate of 2.58 kg m^(-2)h^(-1)in brine.Additionally,the LM/PAN evaporator demonstrates a superior purification performance for seawater,with the concentration of Na^(+),Mg^(2+),K^(+)and Ca^(2+)in real seawater dramatically decreased by three orders to less than 7 mg L^(-1) after desalination under light irradiation.The multiscale LM/PAN evaporator with hierarchical structure regulates the water transportation as well as thermal management for highly effective solar-driven evaporation,providing valuable insight into the structural design principles for advanced SSG systems.
基金financially supported by the National Natural Science Foundation of China(Nos.52203169,52203135 and 52403153)foundation of Yangtze Delta Region Institute(Huzhou)of UESTC(No.U03220149)+2 种基金Huzhou Science and Technology Program Projects(No.2023GZ18)Zhejiang Postdoctoral Research Project(No.ZJ2023133)Science and Technology Cooperation Fund Program of Chengdu-Chinese Academy of Sciences(2023-2025).
文摘Polymer fibers are an important class of materials throughout human history,evolving from natural fibers such as cotton and silk to modern synthetic fibers such as nylon and polyester.With the advancement of materials science,the development of new fibers is also advancing.Polymer fibers based on dynamic covalent chemistry have attracted widespread attention due to their unique reversibility and responsiveness.Dynamic covalent chemistry has shown great potential in improving the spinnability of materials,achieving green preparation of fibers,and introducing self-healing,recyclability,and intelligent response properties into fibers.In this review,we divide these fiber materials based on dynamic covalent chemistry into monocomponent fibers,composite fibers,and fiber membranes.The preparation methods,structural characteristics,functional properties,and application performance of these fibers are summarized.The application potential and challenges of fibers based on dynamic covalent chemistry are discussed,and their future development trends are prospected.
基金Project supported by the National Natural Science Foundation of China(Nos.12072003 and 12372003)Beijing Natural Science Foundation of China(No.1222001)。
文摘Owing to their high flexibility and directional actuation capabilities,macro fiber composites(MFCs)have attracted significant attention for the active control of structures,especially in the nonlinear vibration suppression applications for large-scale flexible structures.In this paper,an MFC-based self-feedback system is introduced for the active control of geometrically nonlinear steady-state forced vibrations in functionally graded carbon nanotube reinforced composite(FG-CNTRC)plates subject to transverse mechanical loads.Based on the first-order shear deformation theory and the von Kármán nonlinear strain-displacement relationship,the nonlinear vibration control equations of the plate with MFC sensor and actuator layers are derived by Hamilton's principle.These equations are discretized by the finite element method(FEM),and solved by the Newton-Raphson and direct iterative methods.A velocity feedback control algorithm is introduced,and the effects of the control gain and the MFC actuator position on the nonlinear vibration active control effectiveness are analyzed.Additionally,a nonlinear resonance analysis is carried out,considering the effects of carbon nanotube(CNT)volume fraction and distribution type.The results indicate that the intrinsic characteristics of the structures significantly influence the vibration behavior.Furthermore,the appropriate selections of control gain and MFC position are crucial for the effective active control of the structures.The present work provides a promising route of the active and efficient nonlinear vibration suppression for various thin-walled structures.
基金support of the National Natural Science Foundation of China(61971301)In part by the Central Guidance on Local Science and Technology Development Fund of Shanxi Province under Grant YDZJSX2021A018+1 种基金Shanxi Province Higher Education Science and Technology Innovation Plan Project(2022L060)the Fundamental Research Program of Shanxi Province(Nos.202203021212227,202303021212082).
文摘The poor surface antibacterial properties are one of the important factors limiting the application of Carbon Fibers Reinforced Polyetheretherketone (CFR-P) composites as artificial bone replace materials. Some of the Two-Dimensional (2D) nanomaterials with unique lamellar structures and biological properties have been demonstrated to have excellent antibacterial properties. Antibacterial properties can be improved by feasible chemical strategies for preparing 2D nanomaterials coating on the surface of CFR-P. In this work, Black Phosphorus (BP) coating was prepared on the originally chemically inert CFR-P surface based on wet chemical pretreatment. The physical and chemical properties, including surface microstructure, chemical composition and state, roughness and hydrophilicity were characterized. The antibacterial ratios against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Streptococcus mutans (S. mutans) were evaluated. The results indicated that hydrophilicity of BP coating on CFR-P was significantly higher compared to that of the pure CFR-P. Wet chemical pretreatment using mixed acid reagents (concentrated sulfuric acid and concentrated nitric acid) introduced hydroxyl, carboxyl and nitro groups on CFR-P. The BP coating exhibited the antibacterial rate of over 98% against both S. aureus and E. coli. In addition, the antibacterial rate of BP coating against the main pathogenic bacteria of dental caries, Streptococcus mutans, reached 45%.
基金supported by the National Key Research and Development Program Project of China(Grant No.2018YFB1106700).
文摘Polyether ether ketone(PEEK)-based continuous glass fiber reinforced thermoplastic composite offers advantages such as high strength,electrical insulation,and heat insulation.Parts manufactured using this composite and 3D printing have promising applications in aerospace,automobile,rail transit,etc.In this paper,a high-temperature melt impregnation method was used to successfully prepare the 3D printing prepreg filaments of the aforementioned composite.In the FDM 3D printing equipment,a nozzle of high thermal conductivity and wear-resistant copper alloy and a PEEK-based carbon fiber thermoplastic composite build plate with uniform temperature control were innovatively introduced to effectively improve the quality of 3D printing.The porosity of the 3D printed samples produced from the composite prepreg filament was analyzed under different printing parameters,and the mechanical properties and fracture mechanism of the printed parts were studied.The results show that the printing layer thickness,printing speed,printing temperature and build plate temperature have varying effects on the porosity of printed parts,which in turn affects tensile strength and the interlaminar shear strength(ILSS).When the printing layer thickness is 0.4 mm,printing speed is 2 mm/s,nozzle temperature is 430℃ and build plate temperature is 150℃,the tensile strength and ILSS of the composite printed parts reach their maximum values of 463.76 and 24.95 MPa,respectively.Microscopic analysis of the fracture morphology of the tensile specimens reveals that the 3D printed CGF/PEEK composite sample has three types of fracture mode,which are single filament bundle fracture,fracture mode of delamination,and fracture failure of the sample at the cross-section.The essence of the above three kinds of fracture mode is the difference of the interface bonding force of 3D printed CGF/PEEK composites.The fracture failure at the cross-section is that the continuous glass fibers in the composite are pulled out until they break,which is the main form of the failure of the composite under tensile load.The interfacial region of the composite is prone to microscopic defects such as voids and delamination during 3D printing,which become the most vulnerable link of the composite.Understanding the relationship between voids and fracture behavior lays a foundation for defect suppression and performance improvement of subsequent printed parts.
基金supported by the National Natural Science Foundation of China(No.51872232)the Key Scientific and Technological Innovation Research Team of Shaanxi Province(No.2022TD-31)the Key R&D Program of Shaanxi Province(No.2021ZDLGY14-04).
文摘Carbon fiber/phenolic resin composites have great potential application in the field of electronic information,where excellent structural-functional integration is required.In this work,the establishment of interfacial structures consisting of carbon nanotubes with different morphologies at the fiber/matrix interface is conducive to the further modulation of the mechanical,tribological,electromagnetic interference(EMI)shielding and thermal conductivity properties of carbon fiber/phenolic resin composites.Specially,array carbon nanotubes can deep into the resin matrix,effectively hindering crack extension,and constructing an electrically and thermally conductive network.Compared with the carbon fiber/phenolic composites,the tensile strength and modulus of elasticity(163.86±9.60 MPa,5.06±0.25 GPa)of the array carbon nanotubes reinforced carbon fiber/phenolic composites were enhanced by 57.09%and 22.22%.The average friction coefficient and wear rate(0.20±0.02,1.11×10^(-13)±0.13×10^(-13)m^(3)N^(−1)m^(−1))were reduced by 39.39%and 74.31%.EMI shielding effectiveness up to 40 dB in the X-band at 0.4 mm sample thickness,diffusion coefficient(0.39±0.003 mm^(2)/s)and thermal conductivity(0.54±0.004 W/(m K))were enhanced by up to 14.37%and 50.42%.This study reveals the beneficial effects of morphological changes of carbon nanotubes on the design of interfacial structure,proposes the reinforcement mechanism of array carbon nanotubes,and opens up the prospect of carbon fiber/phenolic composites for electronic applications.
基金the National Natural Science Foundation of China(No.52070052)the National Natural Science Foundation of China(No.52300082)+3 种基金National Key Research and Development Program of China(No.2022YFB3805903)the State Key Laboratory of Urban Water Resource and Environment in HIT of China(No.2022TS14)the China Postdoctoral Science Foundation(No.2023M730881)Postdoctoral Fellowship Program of CPSF(No.GZB20230964)。
文摘Solar interfacial evaporation(SIE),is currently one of the most potential water supply technologies in the remote,insular,and disaster-stricken areas.However,the existence of volatile organic compounds(VOCs)in water deteriorates the distillate quality,threatening human health.Herein,we constructed a carbonbased bimetallic(C/FeCo)photothermal membrane by electrospinning technique.Results illustrated that the membrane can catalytically degrade VOCs during SIE with persulfate(PDS)mediation.PDS,as well as phenol,was mainly reacted on the interface of the photothermal membrane instead of in the bulk solution.The interception efficiency of phenol achieved nearly 100%using the C/FeCo membrane during SIE.Hydroxyl radical(•OH),sulfate radical(SO_(4)•−),superoxide radical(O_(2)•−),and singlet oxygen(^(1)O_(2))were identified as the main active substances to degrade VOCs.We also conducted SIE experiments using actual river water to evaluate the practical performance of the C/FeCo membrane.This work holds the promise of VOCs interception during SIE and enlarges the application of solar distillation in water/wastewater treatment.
基金supported by Key Laboratory of Higheffciency and Clean Mechanical Manufacture at Shandong University,Ministry of Education,the National Natural Science Foundation of China(Nos.52305484,52305475,and U23A20632)the China Postdoctoral Science Foundation(No.2024M761876)+7 种基金the Youth Innovation Team Program of Universities in Shandong Province(No.2024KJH166)the National Key Research and Development Program of China(No.2023YFC2413301)the Taishan Scholars Program(No.tsqn202408242)the Shandong Provincial Natural Science Foundation(Nos.ZR2022QE053 and ZR2022QE159)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515111124)the Major Scientific and Technological Innovation Project of Shandong Province(No.2023CXGC010207)the Major Basic Research of Shandong Provincial Natural Science Foundation(No.ZR2023ZD34)the talent research project for the pilot project of integrating science,education,and industries of Qilu University of Technology(Shandong Academy of Sciences)(No.2024RCKY009)。
文摘Fiber reinforced ceramic matrix composites(FRCMCs)are the preferred materials for safety critical components in the fields of aerospace,nuclear engineering,and transportation,with broad market and application prospects.However,due to the characteristics of multiphase,heterogeneity,and anisotropy,key issues such as poor adhesion,high porosity,and crack propagation urgently need to be addressed in the fabrication and machining of FRCMCs.With the increasing demand for FRCMCs parts,high-quality and reliable design and fabrication,performance evaluation,and precision manufacturing have become a series of hot issues.There is a lack of systematic review in capturing the current research status and development direction of FRCMCs fabrication and machining.This research aims to comprehensively review and critically evaluate the existing understanding of the fabrication and machining of FRCMCs.This study can provide scientists with a deeper understanding of the shape control mechanism of FRCMCs fabrication and machining,the theoretical basis of material synchronous removal,machining performance,and development direction.Firstly,the basic characteristics and application background of FRCMCs are introduced.Secondly,by comparing and analyzing the typical fabrication process of FRCMCs,the advantages,disadvantages,and performance evaluation of different processes are comprehensively evaluated.Thirdly,the material removal mechanisms and machining performance evaluation standards of traditional mechanical machining technologies(drilling,milling,grinding)and non-traditional mechanical machining technologies(ultrasonic,laser,water jet,discharge,wire saw,and multi-field hybrid machining)are discussed and analyzed.Finally,the challenges,development trends,and prospects faced by FRCMCs in the fields of fabrication,machining,and application are analyzed.This study not only elucidates the basic processes and key difficulties in the fabrication of FRCMCs,but also provides valuable insights for low-damage machining.
基金Project(51072235) supported by the National Natural Science Foundation of ChinaProject(11JJ1008) supported by the Natural Science Foundation of Hunan Province,China+2 种基金Project(20110162110044) supported by the PhD Program Foundation of Ministry of Education of ChinaProject(7433001207) supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject(2001JF3215) supported by Hunan Provincial Science and Technology Plan,China
文摘Piezoelectric materials are capable of actuation and sensing and have been used in a wide variety of smart devices and structures.Active fiber composite and macro fiber composite are newly developed types of piezoelectric composites,and show superior properties to monolithic piezoelectric wafer due to their distinctive structures.Numerous work has focused on the performance prediction of the composites by evaluation of structural parameters and properties of the constituent materials with analytical and numerical methods.Various applications have been explored for the piezoelectric fiber composites,including vibration and noise control,health monitoring,morphing of structures and energy harvesting,in which the composites play key role and demonstrate the necessity for further development.
基金Project(51375369)supported by the National Natural Science Foundation of ChinaProject(SYG201137)supported by the Science and Technology Development Program of Suzhou,China
文摘To improve the manufacture efficiency and promote the application of composites in the automobile industry, a new composite forming method, thermal stamping, was discussed to form composite parts directly. Experiments on two typical stamping processes, thermal bending and thermal deep drawing, were conducted to investigate the forming behavior of composite sheets and analyze the influence of forming temperature on the formed composite part. Experimental results show that the locking angle for woven composite is about 30°. The bending load is smaller than 5 N in the stamping process and decreases with the increase of temperature. The optimal temperature to form the carbon fiber composite is 170 ℃. The die temperature distribution and the deformation of composite sheet were simulated by FEA software ABAQUS. To investigate the fiber movement of carbon woven fabric during stamping, the two-node three-dimension linear Truss unit T2D3 was chosen as the fiber element. The simulation results have a good agreement to the experimental results.
文摘A cohesive zone model is employed to simulate the fiber/matrix interface damage of composites with ductile matrix. The study is carried out to investigate the dependence of the interface damage and the composite tensile strength on the micro parameters of the composite. These parameters contain fiber packing pattern, fiber volume fraction, and the modulus ratio of the fiber to the matrix. The investigation reveals that though the high fiber vo lume fraction, the high fiber′s modulus and the square fiber packing can supply strong reinforcement to the composite, the interface damage is susceptible in these cases. The tensile strength of the composite is dominated by the interface strength when the interface debonding occurs.
