Effects of Fiber Volume Fraction on Damping Properties of Three-Dimensional and Five-Directional Braided Composites

The effects of fiber volume fraction on damping properties of carbon fiber three-dimensional and five-directional( 3D-5Dir)braided carbon fiber / epoxyres in composite cantilever beams were studied by experimental modal analysis method. Meanwhile,carbon fiber plain woven laminated / epoxy resin composites with different fiber volume fraction were concerned for comparison. The experimental result of braided specimens shows that the first three orders of natural frequency increase and the first three orders of the damping ratios of specimens decrease, when the fiber volume fraction increases. Furthermore,larger fiber volume fraction will be valuable for the better anti-exiting property of braided composites,and get an opposite effect on dissipation of vibration energy. The fiber volume fraction is an important factor for vibration performance design of braided composites. The comparison between the braided specimens and laminated specimens reveals that 3D braided composites have a wider range of damping properties than laminated composites with the same fiber volume fractions.

Three-dimensional simulation of sintering crunodes of metal powders or fibers by level set method

The difference of sintering crunodes of metal powders and fibers is discussed. The mathematical model of the surface diffusion described by the difference in mean curvature is defined as a Hamilton-Jacobi-type equation, and the model is numerically solved by the level set method. The three-dimensional numerical simulations of two metal powders and fibers(the fiber angle is 0° or 90°) are implemented by this mathematical model, respectively. The numerical simulation results accord with the experimental ones. The sintering neck growth trends of metal powders and metal fibers are similar. The sintering neck radius of metal fibers is larger than that of metal powders. The difference of the neck radius is caused by the difference of geometric structure which makes an important influence on the curvature affecting the migration rate of atoms.

Eyewear-style three-dimensional endoscope derived from microstructured polymer fiber with the function of image transmission

A method of fabricating multi-core polymer image fiber is proposed.Image fiber preform is fabricated by stacking thousands of polymer fibers each with a 0.25-mm diameter orderly in a die by only one step.The preform is heated and stretched into image fiber with an outer diameter of 2mm.Then a portable eyewear-style three-dimensional（3D） endoscope system is designed,fabricated,and characterized.This endoscopic system is composed of two graded index lenses,two pieces of 0.35-m length image guide fibers,and a pair of oculars.It shows good ？exibility and portability,and can provide the depth information accordingly.

Fabrication and formation mechanism of NbC_x-C three-dimensional netted fibers

Micrometer NbC_x-C three-dimensional netted fibers were synthesized by thecarbothermal method under 0.1 MPa of N_2 ambient atmosphere at a relatively low temperature. Rawmaterials were commercial powders of Nb_2O_5 (99.95 percent), reactive carbon (99.99 percent), NaCl(99.95 percent) and sucrose (99.94 percent). The relationship of the fabrication processing with thecomposition, crystal structure and morphology of fibers was investigated. The formation mechanismwas also proposed and discussed.

Using Acoustic Emissions to Detect Damage in Three-Dimensional Braided Composites

Three-dimensional(3D)braided composites with better properties have been used in some particular industries.Some have had obvious signs of crack when they are braided.Others have had catastrophic failures occuring without warning.A new methodology for the analysis of failure modes in composite materials by means of acoustic emission techniques has been developed.The occurrence of fiber-breakage during tensile loading tests has been observed by the acoustic emission technology.Using acoustic emission technology is investigated as a means of monitoring 3D braided composites structures,detecting damage,and predicting impending damage.Some of the findings of the research project were presented.

CFD Simulation of the Filtration Performance of Fibrous Filter Considering Fiber Electric Potential Field

Aiming at disclosing the quantitative e ects of Coulomb forces on the ltration e ciency of aerosol particles, a three- dimensional random ber model was established to describe the microstructure of brous lters. Then, computational mod- els including the ow model, particle model, and electric eld model were constructed to estimate the ltration e ciency using the Fluent custom user-de ned function program, neglecting the non-uniformity of the ber potential and the particle charge distribution. The simulation results using the established models agreed with the data in the literature. In particular, the electric eld force was found to be one of the important factors required to improve the ltration e ciency estimation accuracy for the ultra ne particles. Moreover, the variation tendencies of the ltration e ciency and the pressure drop of brous lters were studied based on the in uence factors of the ber potential, particle charge-to-mass ratio, solid volume fraction, ber diameter, and face velocity. The established models and estimated results will provide important guidance on the design of high-e ciency particulate air lters for aerosol particles.

Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

Mechanical behavior and permeability properties of sustainable and high-performance anisotropic three-dimensional printable concrete

Three-dimensional printable concrete requires further development owing to the challenges encountered,including its brittle behavior,high cement requirement for the buildability of layers,and anisotropic behavior in different directions.The aim of this study is to overcome these challenges.First,three-dimensional printable concrete mixtures were prepared using silica fume,ground blast furnace slag,and metakaolin,instead of cement,to reduce the amount of cement.Subsequently,the rheological and mechanical behaviors of these concretes were investigated.Second,threedimensional printable concrete mixtures were prepared using 6-mm-long steel and synthetic fibers to eliminate brittleness and determine the effect of those fibers on the anisotropic behavior of the concrete.As a result of this study,it is understood that printable concretes with extremely low permeability and high buildability can be achieved using mineral additives.In addition,results showed that three-dimensional concrete samples containing short steel fibers achieve fracture energies up to 36 times greater than that of plain concrete.Meanwhile,its characteristic length values,as indicators of ductility,are 22 times higher than those of plain concrete.The weakest strength was recorded at the interfaces between layers.The bending and splitting tensile strengths of three-dimensional printed plain concrete samples were 15%and 19%lower than those of casted samples,respectively.However,the addition of fibers improved the mechanical strength of the interfaces significantly.

Advanced treatment of wet-spun acrylic fiber manufacturing wastewater using three-dimensional electrochemical oxidation

A three-dimensional electrochemical oxidation （3D-EC） reactor with introduction of activated carbon （AC） as particle micro-electrodes was apphed for the advanced treatment of secondary wastewater effluent of a wet-spun acrylic fiber manufacturing plant. Under the optimized conditions （current density of 500 A/m2, circulation rate of 5 mL/min, AC dosage of 50 g, and chloride concentration of 1.0 g/L）, the average removal efficiencies of chemical oxygen demand （CODer）, NH3-N, total organic carbon （TOC）, and ultraviolet absorption at 254 nm （UV2s4） of the 3D-EC reactor were 64.5%, 60.8%, 46.4%, and 64.8%, respectively; while the corresponding effluent concentrations of CODcr, NH3-N, TOC, and UV2s4 were 76.6, 20.1, and 42.5 mg/L, and 0.08 Abs/cm, respectively. The effluent concentration of CODer was less than 100 mg/L, which showed that the treated wastewater satisfied the demand of the integrated wastewater discharge standard （GB 8978-1996）. The 3D-EC process remarkably improved the treatment efficiencies with synergistic effects for CODer, NH3-N, TOC, and UV2s4 during the stable stage of 44.5%, 38.8%, 27.2%, and 10.9%, respectively, as compared with the sum of the efficiencies of a two-dimensional electrochemical oxidation （2D-EC） reactor and an AC adsorption process, which was ascribed to the numerous micro-electrodes of AC in the 3D-EC reactor. Gas chromatography mass spectrometry （GC-MS） analysis revealed that electro- chemical treatment did not generate more toxic organics, and it was proved that the increase in acute biotoxicity was caused primarily by the production of free chlorine.

Designing metal-organic framework fiber network reinforced polymer electrolytes to provide continuous ion transport in solid state lithium metal batteries

Polyethylene oxide(PEO)-based solid-state electrolytes are considered ideal for electrolyte materials in solid-state lithium metal batteries(SSLMBs).However,practical applications are hindered by the lower conductivity and poor interfacial stability.Here,we propose a strategy to construct a three-dimensional(3D)fiber network of metal-organic frameworks(MOFs).Composite solid electrolytes(CSEs)with continuous ion transport pathways were fabricated by filling a PEO polymer matrix in fibers containing interconnected MOFs.This 3D fiber network provides a fast Li+transport path and effectively improves the ionic conductivity(1.36×10^(-4) S·cm^(-1),30℃).In addition,the network of interconnected MOFs not only effectively traps the anions,but also provides sufficient mechanical strength to prevent the growth of Li dendrites.Benefiting from the advantages of structural design,the CSEs stabilize the Li/electrolyte interface and extend the cycle life of the Li-symmetric cells to 3000 h.The assembled SSLMBs exhibit excellent cycling performance at both room and high temperatures.In addition,the constructed pouch cells can provide an areal capacity of 0.62 mA·h·cm^(-2),which can still operate under extreme conditions.This work provides a new strategy for the design of CSEs with continuous structure and stable operation of SSLMBs.

Filter Paper-Derived Three-Dimensional Carbon Fibers Film Supported Fe3O4 as a Superior Binder-Free Anode Material for High Performance Lithium-Ion Batteries

Highly uniform and tight adhering of Fe3O4 particles on carbon fiber film（Fe3O4/CFF） is achieved through a simple in-situ thermal oxidation method. Particularly, 3D CFF with interconnected structure can shorten transfer path and buffer the volume expansion during charge-discharge cycling. Herein, the obtained Fe3O4/CFF anode exhibits a stable cycling performance and excellent high rate capability. The cell delivers a reversible capacity of 1 711 m A·g^（–1） at a current density of 100 m A·g^（–1） after 100 cycles. Even at a high rate density of 2 A·g^（–1）, the specific capacity also can maintain 1034 m A·g^（–1） after 100 cycles. The simplified fabrication is featured with low-cost and this binder-free perspective holds great potential in mass-production of high-performance metal oxide electrochemical devices.

Sustainable and untethered soft robots created using printable and recyclable ferromagnetic fibers

Integrated printing of magnetic soft robots with complex structures using recyclable materials to achieve sustainability of the soft robots remains a persistent challenge.Here,we propose a kind of ferromagnetic fibers that can be used to print soft robots with complex structures.These ferromagnetic fibers are recyclable and can make soft robots sustainable.The ferromagnetic fibers based on thermoplastic polyurethane(TPU)/NdFeB hybrid particles are extruded by an extruder.We use a desktop three-dimensional(3D)printer to demonstrate the feasibility of printing two-dimensional(2D)and complex 3D soft robots.These printed soft robots can be recycled and reprinted into new robots once their tasks are completed.Moreover,these robots show almost no difference in actuation capability compared to prior versions and have new functions.Successful applications include lifting,grasping,and moving objects,and these functions can be operated untethered wirelessly.In addition,the locomotion of the magnetic soft robot in a human stomach model shows the prospect of medical applications.Overall,these fully recyclable ferromagnetic fibers pave the way for printing and reprinting sustainable soft robots while also effectively reducing e-waste and robotics waste materials,which is important for resource conservation and environmental protection.

Ablation Performance of a Novel Super-hybrid Composite

A novel super-hybrid composite (NSHC) was boron-modified phenolic resin (BPR) with three-dimensional reticulated SiC ceramic (3DRC) and high silica fibers. Ablation performance of the NSHC was studied. The results show that the linear ablation rate of NSHC was lower than that of pure BPR and the high silica/BPR composite. Its linear ablation rate is 1/17 of the high silica/BPR. Mass ablation rate of the NSHC is very close to that of the pure BPR and the high silica/BPR composite. Scanning electron microscope (SEM) analysis indicates that 3DRC has scarcely changed its shape at the ablation temperature. Its special reticulated structure can restrict the materials deformation and prevent high velocity heat flow from eroding the surface of the materials largely and thus increase ablation resistance of the NSHC.

Scanning electron microscopic observation:three-dimensional architecture of the collagen in hepatic fibrosis rats

Background In the process of hepatic fibrosis, the accumulation of collagen fibers is strongly related to the hepatic function. The aim of this study was to investigate the three-dimensional architecture of the collagen network in the liver of rats with hepatic fibrosis. Methods Healthy adult male Wistar rats （n=32） were randomly divided into a control group （n=16） and a hepatic fibrosis group （n=16）. In the control group, the rats were treated with peanut oil while the rats in hepatic fibrosis group were treated for 10 weeks with 60% CCI4 diluted in peanut oil. The quantity of collagen fibers was detected by Western blotting; distribution of the collagen was detected by sirius red staining and polarized microscope; the three-dimensional architecture of collagen in the liver was observed under the scanning electron microscope after fixed tissues were treated with cell-maceration using NaOH. Statistical analysis was performed using the u test. Results The quantity of collagen fibers increased significantly in the hepatic fibrosis group. With the aggravation of hepatic fibrosis, collagen fibers gradually accumulated. They interlaced the reticulation compartment and formed a round or ellipse liver tissue conglomeration like a grape framework that was disparate and wrapped up the normal liver Iobule. The deposition of collagen fibers was obvious in adjacent hepatic parenchyma, especially around the portal tracts. Conclusion Our experiment showed the collagen proliferation and displays clearly the three-dimensional architecture of collagen fibers in rat liver with hepatic fibrosis by scanning electron microscope. It can provide a morphological foundation for the mechanisms of changed haemodynamics and portal hypertension in hepatic fibrosis.

Facile and Large-scale Fabrication of Self-crimping Elastic Fibers for Large Strain Sensors

Stretchable conductive fibers offer unparalleled advantages in the development of wearable strain sensors for smart textiles due to their excellent flexibility and weaveability.However,the practical applications of these fibers in wearable devices are hindered by either contradictory properties of conductive fibers(high stretchability versus high sensing stability),or lack of manufacturing scalability.Herein,we present a facile approach for highly stretchable self-crimping fiber strain sensors based on a polyether-ester(TPEE)elastomer matrix using a side-by-side bicomponent melt-spinning process involving two parallel but attached components with different shrinkage properties.The TPEE component serves as a highly elastic mechanical support layer within the bicomponent fibers,while the conductive component(E-TPEE)of carbon black(CB),multiwalled carbon nanotubes(MWCNTs)and TPEE works as a strain-sensitive layer.In addition to the intrinsic elasticity of the matrix,theTPEE/E-TPEE bicomponent fibers present an excellent form of elasticity due to self-crimping.The self-crimping elongation of the fibers can provide a large deformation,and after the crimp disappears,the intrinsic elastic deformation is responsible for monitoring the strain sensing.The reliable strain sensing range of theTPEE/E-TPEE composite fibers was 160%-270%and could be regulated by adjusting the crimp structure.More importantly,the TPEE/E-TPEE fibers had a diameter of 30-40 pm and tenacity of 40-50 MPa,showing the necessary practicality.This work introduces new possibilities for fiber strain sensors produced in standard industrial spinning machines.

2D Fusion Simulations and Experimental Confirmations of Print Paths Using Composite Particles with Particle Method for Fused Filament Fabrication

Printing short fibre/thermoplastic composites using the fused filament fabrication method sometimes creates a gap between print paths. In this study, the two-dimensional moving particle semi-implicit method for liquid simulation was applied to simulate the print-path fusion process. The three-dimensional movement of the nozzle was simulated using the sliding motion of the nozzle. The method was applied to the printing of short carbon fibre/polyamide-6 composites, and the simulation results were compared with those of experiments. The simulated results of the cross-sectional configuration agreed well with the experimental results. This will enable the optimization of printing process parameters thus reducing the gap between print paths.

Stress Distribution in Maxillary Central Incisors without Ferrules: A Finite Element Analysis of Post and Core Systems

Purpose: The purpose of this study was to identify optimal post and core materials for central incisors without ferrules using three-dimensional finite element analysis and three-point bending tests. Methods: Stress analyses were performed with six models: cast metal post and core (MP), composite resin core alone, straight fiber-reinforced post-composite resin core (FSR), tapered fiber-reinforced post-composite resin core, straight titanium post-composite resin core (TSR), and tapered titanium post-composite resin core (TTR). A 100-N load was applied to the lingual surface at a 45° angle to the long axis of the tooth. Maximum von Mises stress distributions were calculated with finite element analysis software. Five samples each of composite resin, straight fiber-reinforced post, straight titanium post, straight fiber-reinforced post and composite resin, and straight titanium post and composite resin were subjected to three-point bending tests, followed by analysis of variance and Tukey’s multiple comparison test. Results: Stress distribution was optimal on TTR. Maximum von Mises stress on the cervical side of the post was greatest in TSR (693 MPa) and TTR (556 MPa). Maximum stress on the apical side of the post was greatest in MP (110 MPa). Maximum stress in surrounding dentin was lowest in MP (203 MPa) and TTR (250 MPa). Gap distance was smallest in MP (0.09 mm) and largest in FSR (0.26 mm). Mean maximum three-point bending force was lowest in composite resin (26.9 N/mm) and highest in titanium post and composite resin (97.1 N/mm). Titanium post bending strength was consistently greater than that of the fiber-reinforced post (p < 0.01). Conclusion: These results revealed optimal stress distribution and high bending strength with the tapered titanium post and resin combination, suggesting that this combination can most effectively prevent root or post fracture in an anterior tooth without a ferrule.

Fabrication and morphology of NbC_x-C composite three-dimensinal netted fibers

The raw materials were commercial powders of Nb2O5 (99.95%), reactive carbon (99.99%), NaCI (99.95%) and sucrose (99.94%). By the carbothermal method, the NbCx (x= 0.98)-C composite three-dimensional netted fibers were prepared in graphite resistance furnace in 0.1 MPa/N2 ambient atmosphere at temperature from 970 to 1 120℃. The diameters of composite three-dimensional netted fibers are 12-38 μm, the hole circumferences of netted fibers are 0.22-2.2 mm, and the hole diameters are 70-701 μm. The process conditions for fabricating NbCx-C composite three-dimensional netted fibers and related morphology, composition and crystal structure of NbCx-C composite netted fibers were investigated in detail.

Study on 3D CFBG Vibration Sensor and Its Application

A novel variety of three dimensional （3D） vibration sensor based on chirped fiber Bragg grating （CFBG） is developed to measure 3D vibration in the mechanical equipment field. The sensor is composed of three independent vibration sensing units. Each unit uses double matched chirped gratings as sensing elements, and the sensing signal is processed by the edge filtering demodulation method. The structure and principle of the sensor are theoretically analyzed, and its performances are obtained from some experiments and the results are as follows： operating frequency range of the sensor is 10Hz - 500Hz; acceleration measurement range is 2m.s-2 - 30m.s-2; sensitivity is about 70 mV/m.s-2; crosstalk coefficient is greater than 22 dB; self-compensation for temperature is available. Eventually the sensor is applied to monitor the vibration state of radiation pump. Seen from its experiments and applications, the sensor has good sensing performances, which can meet a certain requirement for some engineering measurement.