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Rational compositions of a polymer composite material are proposed and technological prerequisites for manufacturing technical products for chemical engineering, based on liquid resol phenol–formaldehyde resins and dispersed fibrous filler manufactured by mechanical processing of the organic waste from fiber production in the pulp and paper industry are evaluated. Methods and parameters of technological stages, including the preparation of raw materials and their mixtures, production of a polymer dispersed filled press material, and hot molding (pressing) products, were determined and tested. Recommendations are given on the hardware and process design of the technological stages of the production of a quality polymer composite material and improvement of its properties. The regularities of changes in the physical and mechanical properties (response on compression, tension, and bending, as well as impact strength and moisture and oil absorption) of the composites with the concentration of dispersed fibrous filler at the recommended thermal pressing parameters (temperature 170 °C, specific pressure 20 MPa, exposure time 1 min/ 1 mm product thickness). Clear evidence is provided showing that the upper limit of the percentage of dispersed fibrous filler in the studied phenolic samples is 40-60%, and at higher percentages the mechanical parameters are strongly deteriorated and the moisture and oil absorptions become much higher than the limits permitted by standards for technical phenolic plastics. The results of the study make it possible to recommend the compositions based on liquid resol phenol–formaldehyde resins and modified fibrous waste from the pulp and paper industry and the hardware and process design for the production of phenolic products of chemical engineering. The developed composites allow homogeneous coloring in various colors (except for white) and imparting to their surface a smooth shiny texture. [ABSTRACT FROM AUTHOR]

The usage of jute/cotton natural composites has surged in almost all fields of engineering due to their advantage of possessing high strength to weight ratio and biodegradability. This paper deals with the fabrication and investigation of mechanical properties of jute/cotton fiber reinforced epoxy composite which is relatively a hybrid composite. In this study, the composite is fabricated by a hand layup process followed by compression molding method with varying the number of layers of composite laminates also with different cutting angles. The composites are prepared with four different proportions of jute/cotton fibers. Various mechanical tests are conducted and the result shows that the 14-layer jute/cotton composite has optimum properties achieved and also observed that 90° has better properties than the others cutting angles. Statistical analysis of composites was done by ANOVA-table; based on mean effective plots, the optimum levels of parameters have been identified, and significant contribution of parameters is determined by analysis of variance Also, failure morphology analysis is done using a scanning electron microscope (SEM) through which the internal structures of the tested specimen are analyzed. [ABSTRACT FROM AUTHOR]

Modified composites, blends, polymers and copolymers are some of those engineered materials which are playing a major and remarkable role in achieving our present sustainable environment. Mechanical, electrical, and biological properties of carbon and native metal nanoparticles are distinctive from others and provide plentiful scaffolds for a wide-range of applications in our lives, including medical devices, pharmaceutical, polymer industry, biomedical field, coating of kitchen appliances, food packaging, clothing, gifts, optical devices, biosensors, antimicrobial objects etc. Distinct chemical and physical properties of silver and carbon-based NPs are considered to act in this way. The antimicrobial and conducting nature of Gr and AgNPs are studied here. There is a vast history of these properties; however, beginners still have a bright future. The antimicrobial activity of these two incorporates antibacterial, antifungal, antiviral, anticancer, antioxidant, antistatic and antibiotic nature. Additionally, both nanomaterials exhibit notable thermal conductivity. Based on these characteristics novel composite/blend materials with enhanced electrical, thermal, antimicrobial, antistatic, and antibiotic effect can be engineered with innovative ideas. This paper expresses the worldwide applications of such nanomaterials. [ABSTRACT FROM AUTHOR]

This paper provides a numerical simulation study of Magnetically Circular Layers of Triboelectric Nanogenerators (MCL-TENGs) for energy harvesting and self-powered sensing. The MCL-TENGs generate electrical energy by means of the conversion of mechanical energy into electrical energy through contact electrification and electrostatic induction. This paper concentrates on the numerical modeling of the copper/aluminum MCL-TENG and compares simulation results with experimental findings. The voltage comparison of copper MCL-TENGs (OC) between experimental and numerical simulations at 2000, 2500, and 3000 rpm showed Cu-EXP configuration voltages ranging from 4.1 to 4.4 V and Cu-FEM setup voltages ranging from 4 to 4.4 V. Meanwhile, aluminum MCL-TENGs showed Al-EXP configuration voltages ranging from 4.08 to 4.35 V and Al-FEM setup voltages ranging from 4 to 4.3 V across the third layer. The system can enhance the energy efficiency and sustainability of coastal bridge infrastructure by harvesting surplus energy from mechanical motion and converting it to electricity for self-powered sensing and monitoring systems. [ABSTRACT FROM AUTHOR]

In this paper, a failure analysis of the TMT90m + composite wind turbine blade performed by combining numerical simulation and full-scale destruction tests is presented. The complex failure characteristics of the skin were studied in detail and a driving relationship was obtained. From the results, it was found that the stress concentration leading to local buckling was due to the geometric and layup nonlinearities of the destruction region. This in turn contributed to the successive occurrence of matrix failure and fiber failure. Further, by using the method of finite element secondary development, the accuracy of four commonly used failure criteria for wind blade failure prediction is discussed. From the results, it was found that the Chang-Chang model has ideal prediction accuracy and is more suitable for engineering applications in blade structure design. [ABSTRACT FROM AUTHOR]

With the development and depletion of shallow coal resources, deep coal mining has gradually become normalized. In the face of increasingly severe corrosion environment of coal mining, it is urgent to develop new materials with excellent corrosion resistance for key parts of coal mining equipment. In this paper, SiC, Al2O3 and SiO2 were used as raw materials to prepare three-dimensional network configuration SiC ceramics by organic foam impregnation method. Then the three-dimensional network configuration SiC-Fe composite was prepared by atmospheric pressure casting process. And by electrochemical test, static immersion corrosion test, scanning electron microscope and first-principles simulation calculation, the corrosion resistance of three-dimensional network configuration SiC-Fe composite in harsh mine water environment was characterized, meanwhile the corrosion resistance mechanism was analyzed. The results show that the corrosion potential increases from - 495.756 mV to -379.626 mV, and the corrosion current density decreases from 3.6864 μA/cm2 to 2.1709 μA/cm2 when the SiC ceramic reinforcement is added. The inhibition efficiency based on polarization curve measurement is increased by 41.11%. The charge transfer resistance increases from 5417 Ω·cm2 to 6437 Ω·cm2, and the capacitance value drops from 159.96 μF·cm−2 to 90.12 μF·cm−2. The inhibition efficiency based on electrochemical impedance spectroscopy is increased by 18.83%. First principles calculations show that the addition of SiC reinforcement showed a greater resistance in preventing the migration of corrosive media to the surface of the Fe substrate and can effectively slow down corrosion, which was consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The paper proposes a method for the formation of superhydrophobic electrochemical coatings based on copper with relatively high mechanical strength. The method of electrodeposition of copper composites with nanodispersed silicon carbide particles is considered as the main approach to obtaining such coatings. Electrochemical codeposition of nanoparticle agglomerates and a copper matrix makes it possible to obtain the required multimodal roughness of coatings. This coating, after treatment with stearic acid, acquires superhydrophobic properties. The paper presents data on the morphology, superhydrophobic properties and chemical composition of coatings. The optimal mode for the formation of such coatings has been determined. According to the results of mechanical tests, the superhydrophobic Cu–SiC composite is superior in resistance to dry friction to many other superhydrophobic coatings formed by electrochemical methods. The resulting coatings have a developed surface morphology, which makes it possible to achieve a wetting angle of 162°. This determines the increased corrosion resistance of copper coated with a superhydrophobic Cu–SiC composite in the salt spray chamber. The time until the first corrosion damages appears on copper in the salt spray chamber increases from several hours (without coating) to 3.5 days (with coating). In this case, the coating continues to remain generally superhydrophobic for more than a day, and after the loss of superhydrophobicity, it remains hydrophobic. [ABSTRACT FROM AUTHOR]

Drone technology is widely available and is rapidly becoming a crucial instrument in the functions of businesses and government agencies worldwide. The demand for delivery services is accelerating particularly since the Covid-19 pandemic. Both companies and customers want these services to be efficient, timely, safe, and sustainable, but these are major challenges. Last-mile delivery by lightweight short-range drones has the potential to address these challenges. However, there is a lack of consistency and transparency in assessing and reporting the sustainability of last-mile delivery services and drones. This paper critically reviews published papers on Life Cycle Assessments of drones to date. The study reveals a lack of comprehensive studies, and a need to examine composite and battery manufacturing developments and provides key considerations for future study development. [ABSTRACT FROM AUTHOR]

Uncertainty is widely present in composite structures, and the probabilistic model is one of the most common ways to describe uncertainty. In some engineering problems, incomplete knowledge leads to uncertainty in the distribution parameters of probabilistic models. In this paper, the uncertainty of the distribution parameters is described by intervals, and the uncertainty analysis of a radome made by honeycomb sandwich composite is performed under imprecise probability. To reduce computational costs, a back propagation analysis neural network (BPA-NN) based on data from finite element analysis (FEA) is constructed. A variance-based global sensitivity analysis (GSA) is conducted to identify input variables that have a large influence on the output characteristics of the composite structure. A buckling failure model is established to evaluate the safety of the composite structure, and then GSA based on failure probability is carried out to identify input variables that have a large influence on the failure probability of the structure. The uncertainty analysis under imprecise probability in this paper provides a framework for the reliability assessment and design of composites. [ABSTRACT FROM AUTHOR]

The bumper is an automotive part act as a protective shield in the vehicle. It bears and absorbs the load when the vehicle incurs a collision. If the bumper has got more weight it leads to more fuel consumption and decreases the fuel efficiency of the vehicle. This problem can be overcome by reducing the weight of the bumper without compromising its performance. The main objective in bumper design and fabrication is that it should possess less weight and at the same time, it should withstand the higher load during a collision. In this paper, the properties and performance of the developed bumper composite are compared with the existing bumper. The bumper performance is optimized using a finite element analysis with ANSYS R15.0. From the cost analysis, it has been observed that the weight and cost of the Basalt composite bumper is 49% and 56% lesser than the steel bumper. The Impact strength and Factor of Safety values of the Basalt fabric composite bumper is 47.6% and 32.5% higher than the steel bumper. The total deformation of the Steel bumper is 15.7 mm, and the Basalt composite bumper is 32 mm, which shows 51% higher deformation than steel. [ABSTRACT FROM AUTHOR]

This study uses an incipient wet impregnation method to look into the structural and dielectric properties of Bentonite that have been changed by adding different amounts of Ce and Zn. X-ray diffraction (XRD) analysis showed that the montmorillonite phase was the most common in Ce- and Zn-doped bentonite. Silicon dioxide (SiO2) and quartz (Q) were also found. Scanning electron microscopy (SEM) demonstrated enhanced platelet aggregation and porous structures in doped compounds. Energy-dispersive X-ray spectroscopy (EDX) confirmed the presence of Si, Al, Na, Ce, Zn, Ca, Mg, Cl, Fe, and K elements. Dielectric analysis, focusing on frequency and temperature dependence, unveiled an inverse relationship between frequency and the dielectric constant. Additionally, a strong correlation between temperature and dielectric properties was established through regression equations, indicating an increase in dielectric constant with temperature. Electric modulus analysis showed dispersion at high frequencies, suggesting charge carrier mobility. The AC conductivity analysis showed that the conductivity consistently decreased as the temperature rose. There were clear frequency-independent plateaus and intrinsic charge carrier relaxation that were seen. A fitting analysis showed that charge carriers hopped and the dielectric relaxed, and adding Ce and Zn made the material less conductive. The novelty of this paper lies in its focus on examining the dielectric characteristics of doped materials based on bentonite, particularly concerning the incorporation of Zn and Ce. Highlights: Investigation of structural and dielectric properties of Bentonite modified with Ce and Zn. Utilization of incipient wet impregnation technique for modification. Enhanced platelet aggregation and porous structures observed in doped compounds via SEM. Dispersion at high frequencies indicated by electric modulus analysis. Decrease in conductivity with rising temperature observed in AC conductivity analysis. Charge carrier hopping, and dielectric relaxation mechanisms identified through fitting analysis. Incorporation of Ce and Zn resulted in reduced conductivity in the materials. [ABSTRACT FROM AUTHOR]

This paper examines the microstructure evolution and thermal properties of Al/Ti composites with different volume fractions of Ti. The laminated composites were first fabricated by the accumulative roll bonding (ARB) process. The fabricated composites were then stacked and bonded together by cold roll bonding process to produce Ti–Al functionally graded composite. The microstructural investigation of ARBed composites revealed that plastic instabilities including necking and rupture took place within composites. As a result, the fragments of Ti were distributed uniformly across the Al matrix. In addition, the SEM images of the Al–Ti functionally graded composite showed a compositional gradient from the Al side to the Ti side. Based on the EBSD maps taken from Al and Ti layers, the grain refinement was successfully achieved during six passes. Besides, with an increase in the volume fraction of Ti, the grains became finer, indicating the gradient in grain size across Al–Ti functionally graded composite. Furthermore, the experimentally measured thermal properties of Al and Ti sheets increased as a function of temperature while they declined by increasing passes. However, thermal conductivity, thermal diffusivity, coefficient of thermal expansion, and specific heat capacity of Al/Ti composites showed a reduction with the rise of Ti content. [ABSTRACT FROM AUTHOR]

The development of thermal energy storage materials applied in various fields has been attracting considerable attention in recent years. In this paper, a series of 1,6-hexanediol (HDL)/silicon dioxide (SiO2) form-stable composite phase change materials (fs-CPCMs) with various mass percentage of HDL loadings were made through sol–gel technique. For HDL/SiO2 fs-CPCMs, HDL was served as PCM, and silica gel was acted as the supporting matrix to keep a stable state without leakage of the composites even the temperature was over 85 °C. The results from form-stability test and DSC measurements showed that the as-prepared fs-CPCM with the mass fraction of HDL at 70 wt% presented good form-stability, suitable melting point (43.5 °C), and reasonable fusion enthalpy of 130.9 J/g. Fourier transform infrared (FT-IR) spectroscopy indicated that only physical adsorption existed between the HDL and silica gel. Moreover, the thermal performance tests showed that the thermal energy storage and release rates of the as-prepared HDL/SiO2 fs-CPCM was enhanced compared to pure HDL. In summary, the as-prepared fs-CPCMs exhibit reasonable latent heats, good thermal stabilities, and reliability, which are promising candidates for energy-saving construction materials. [ABSTRACT FROM AUTHOR]

The paper presents a method for the synthesis of metal pastes and diffusion-hardening alloys based on gallium by intensive vibrational mixing of powder components: solid gallium and a complex of filler powders. Using this method (with a specially selected fractional composition of powdered components), a series of samples of Cu–Ga–Sn alloys were obtained—one of the "classic" systems used (with various additives) as metal solder adhesives and dental filling materials. Structural, thermochemical (DSC), physical and mechanical properties, phase composition of initial and hardened samples are presented. When mixing, dosing and storing the components of the initial powder mixture, there is no noticeable segregation, contact-reactive melting of the components. The production of gallium pastes in this work includes the synthesis of the liquid metal component in situ, in the process of vibration treatment of the powder mixture. In addition to ease of use, this method, apparently, can provide new opportunities for the design of the structure of gallium pastes, putties, hard metal solder adhesives and filling materials. [ABSTRACT FROM AUTHOR]

The static stiffness of machine tools is one of the key parameters influencing the accuracy of dimensions, shape, and relative positioning of the surfaces of workpieces being machined. This paper presents an analysis of the effect of the stiffness of individual structural components on the resulting stiffness of a prototype vertical lathe with a steel-polymer concrete main frame. This analysis was carried out using a finite element model of the lathe, which was experimentally verified. It was shown that filling the body with polymer concrete significantly (by 30%) increases the static stiffness and damping of the lathe's steel support system. However, the sensitivity analysis carried out in the paper showed that the tool head bearing stiffness has a more significant effect on the static stiffness of the machine tool. [ABSTRACT FROM AUTHOR]

Nanocellulose-based materials have attracted the scientific community's attention due to their abundance in nature, biocompatibility, high surface area, high strength, low toxicity, and low production cost. These environmental-friendly materials have potential applications for developing hydrogels, aerogels, electrodes, adsorbents, packaging films, membranes, nano papers, filters, biomaterials for biomedical, and composites. The present work monitors scientific reports and patent databases of recent achievements on nanocellulose-based composites used as sorbent materials. Most of the pieces found used non-wood, wood, agro-waste, and microorganism sources to obtain nanocellulose. The search identifies most applications were for removing dyes, heavy metals, odor, organic particles from water, and absorption of hemoglobin and immunoglobulin. In addition, it was possible to confirm fifty patent applications on nanocellulose-based sorbent composites. This review was relevant to evaluate the potentiality of applications about nanocellulose as a based sorbent in composites, giving a systematic overview of what has been made and what could be the new potential sources and applications that would be used in future works of this material. [ABSTRACT FROM AUTHOR]

An analytical model of the interaction between Al and C atoms at the interfaces formed by carbon nanoparticles and aluminum is proposed. The model is convenient for practical use in calculating the free energy of the interface, which is essential for nanocomposites and determines their mechanical, thermophysical, and other properties. The paper considers nanoparticles of various structures that are used in the development of aluminum matrix composites: fullerenes of various diameters, single-layer carbon nanotubes of metal and semiconductor types of various radii and chirality, graphene, and graphite. The proposed model employs the Lennard–Jones potential and approximately takes into account the effect of the local structure of the nanoparticle on the interaction of pairs of aluminum and carbon atoms using additional parameters. In this paper, we assume that the average local curvature of the nanoparticle surface determines the depth and location of the potential well. The work is supplemented with the study of interphase interaction in the framework of the density functional theory. The comparison of the results of calculations performed using approximations of various levels of accuracy is used to establish the limits of applicability of the proposed potential, and the possibility of its application in the study of interfacial interaction in nanocomposites based on aluminum and nanocarbon is shown. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to examine the microstructural evolution and mechanical properties of Ni/Ti laminated composite produced by a cross-accumulative roll bonding (CARB) method. The SEM images showed that no void and delamination were observed which indicates that the layers were strongly bonded together. In addition to the thickness reduction and increased number of interfaces, plastic instabilities took place with an increase in CARB passes; the wavy-like interfaces appeared as a result of the necking and shear bands formation. However, due to the effect of uniform rolling pressure and rotation of rolling direction during the CARB process, all layers remained continuous in all CARB passes. The most marked observation coming from EBSD analyses was the formation of fine grains surrounded by a high fraction of high-angle grain boundaries (HAGBs). Based on the microtexture analyses on Ti and Ni layers, it was found that by increasing the rolling passes, a crystallographic texture formed in Ti layers gradually changes from the basic {0001}<112 ̅0 > system into the system dominated by {0001}<101 ̅0 > prismatic-like orientations. In the case of the crystallographic texture formed in Ni layers, there was a significant increase in the intensity of the Q{013}<231>; P{011}<122 > and Goss {011}<100>, indicating the formation of shear strain-assisted type of texture. Furthermore, with an increase in the CARB passes, the mechanical properties improved due to strong interfaces and grain refinement. The maximum values of the yield strength, tensile strength, and elongation reached 842 MPa, 936 MPa, and 7.1% respectively, in the final CARB pass. In addition, ductile fracture mainly occurred on fracture surfaces of Ti and Ni layers even though by increasing passes, cleavage facets appeared due to strain hardening. [ABSTRACT FROM AUTHOR]

In this paper, polypyrrole (PPy) composites (PPy-BC) filled with boron carbide (BC) at different ratios were synthesized for the sorption of carcinogenic methyl orange (MO) dye from aqueous media. In sorption experiments, first, optimum process parameters including operating time (0–210 min), adsorbent mass (0.01–0.30 g/50 mL), concentration (10–50 mg/L), and pH (2–12) were determined. The raw data obtained from the sorption tests were applied to the various isotherms and the Langmuir model showed the best results. From Langmuir isotherm model, the maximum sorption capacities for pristine BC, pristine PPy, and PPy-BC-10 composite were calculated as 208.3, 285.7, and 222.2 mg/g at 25 °C, pH 7, and 10–50 mg/L, respectively. It was determined that the sorption process followed the pseudo-second-order kinetic and the chemisorption process occurred. From the enthalpy values, it was determined that the process was endothermic for pristine BC (+ 40.82 kJ/mol) and pristine PPy (+ 27.33 kJ/mol), and exothermic for PPy-BC-10 (− 7.48 kJ/mol). It can be said that the sorption process of MO dye on composites can be realized by electrostatic interactions, π–π interactions, H-bonding, and pore diffusion. All results showed that the prepared composites could be used as an efficient and potential adsorbent in the sorption of anionic pollutants from an aqueous environment. [ABSTRACT FROM AUTHOR]

A method for calculating the stress-strain state in "fiber-matrix" microstructures ("Van Fo Fy (VFF) method") was developed by the famous scientist in mechanics G. A. Vanin. The method is based on the satisfaction of boundary conditions on the interfaces with application of series of derivatives of doubly-periodic elliptic Weierstrass functions. Problem solutions for various loading conditions of unidirectional fibrous composites have an analytical form expressed in functional series, but their calculation presents considerable difficulties, which, until recently, limited the application and development of the VFF-method. In this paper, in order to explain this method, the derivation of the basic micromechanics relations that make it possible to calculate the stress and strain fields in unidirectional composite structures and, on their basis, to estimate the effective elastic properties of composites with a double-periodic arrangement of fibers was briefly presented. The method also allows us to estimate other effective (averaged over the periodicity cell) physical properties: thermal conductivity, electrical conductivity, magnetic permeability, etc. VFF-method admits extension to multilevel hierarchically organized structures reflecting the structure of natural biocomposites. As illustrations, the paper presents solutions of the problems for unidirectional composites with circular fibers, although the method allows one to solve problems for elliptical, hollow, arbitrarily arranged fibers. For the numerical implementation of the method, which was not carried out before, the analytical relations obtained were brought to algorithms and programs by means of computer algebra. The results of calculations of microstress fields in composite structures with different variants of periodicity of arrangement of elementary cells were presented as the particular examples. Calculations by the VFF-method and the standard numerical finite element method were compared and a good agreement of the results was demonstrated. [ABSTRACT FROM AUTHOR]

As a possible alternative to provide a continuous power supply for small and low-power devices, piezoelectric energy harvesting technology has attracted wide attention in the last decade. This paper developed a kind of flexible d31 type piezoelectric macro fiber composite (MFC) and the MFC cantilever harvester. The vibration energy harvesting properties of the harvester were discussed. The research results show that the MFC cantilever harvester has a good voltage response to the excitation signal, and the largest open circuit voltage amplitude appears at the resonance frequency. The open circuit voltage amplitude of the harvester is sensitive to the vibration acceleration, which increases nearly linearly with increasing the vibration acceleration when the vibration acceleration is less than 2.0 g. The increase of the piezoelectric ceramic fiber volume fraction in the MFC can improve the open circuit voltage of the harvester, but increases the stiffness of the harvester, which is disadvantageous to the long-term operational reliability of the harvester. The desired open circuit voltage or short circuit current can be achieved in practical application by connecting multiple MFCs in series or parallel. [ABSTRACT FROM AUTHOR]

Characterization of the stitched textile preform is required for the prediction of textile preforms forming in the fabrication of composite structures for aerospace applications. The behavior of the preform in compression during resin injection into the preform is one of the critical issues in achieving a high-quality composite for space structures. This paper concentrates on the experimental and finite element analysis of compaction for textile preform. The investigation of the mechanical properties of preforms during compression tests revealed that the formability parameters of a preform can be altered by the stitching process. The load-deformation response, which is depicted in detail, had the greatest influence on the preform deformation. Compression of the stitched preform resulted in less tow undulation in the plane direction and more stitching thread undulation in the thickness direction, while the stitching thread stimulated the preform to endure more pressure. The results provided more detailed insights into the effects of compaction on other properties such as permeability and composite mechanical behavior, which is based on the internal geometry of 3D textile preforms. [ABSTRACT FROM AUTHOR]

Porous materials are pivotal in emerging fields like tissue engineering, scaffold, and drug delivery due to their distinctive porosity-driven functional properties. This paper describes how to achieve multiscale porosity in food-based composites through a thermally activated gelatinization process of amylopectin molecules coupled with 3D printing. By controlling printing paths, macropores are engineered, while degree of gelatinization governs micro- and nanopores formation. Process-microstructure relationship reveals that longer preheating treatments at higher gelatinization temperatures significantly reduce micro-pore area by over twofold and nanopore surface area by over threefold. These results provide a promising route to fabricate food-based composite with tailorable microstructures. [ABSTRACT FROM AUTHOR]

Improving the mechanical properties of high-conductive materials like pure copper without any serious adverse effect on their conductivity attracts more interest in several industries. The aim of this paper is to investigate the mechanical behavior and fracture mechanisms of the copper matrix composites reinforced by steel nanoparticles under tensile, fatigue, and impact loading regimes. Scanning electron microscopy is used to study the fracture mechanisms of the copper matrix composite samples. The fatigue test results show that reinforcing the pure copper with 2.5 wt.% steel nanoparticles improves the fatigue life of the pure copper by 67, 31, and 86 percent in 60, 80, and 100 MPa amplitude stresses, respectively. The results of the tensile tests of the composite samples also show that the composite reinforced by 2.5 wt.% steel nanoparticles has the best combination of tensile and yield strengths and elongation among the present composite grades and pure copper. Further increasing the reinforcement particle content to 5.2 and 7.5 wt.% deteriorates the mechanical strength and fatigue life. However, ductility and almost impact energy increase gradually by increasing the steel nanoparticles' weight percent in the composite grades. The mechanical behavior and fracture mechanisms are validated using micrographs of the fracture surfaces of the test samples, and the micrographs confirm and justify the test results obtained by the mechanical tests. [ABSTRACT FROM AUTHOR]

Mobile communications systems are affected by what is known as fading, which is a well-known problem largely studied for decades. The direct consequence of fading is the complete loss of signal (or a large decrease of the received power). Rayleigh fading is a reasonable model for wireless channels although, Nakagami-m distribution seems better suited to fitting experimental data. In this paper we obtain the Nakagami-m distribution as a composite (mixture) of the Rayleigh distribution, a result which as far as we know it has not been shown in the literature. This representation of the Nakagami-m distribution facilitates computations of the average BER (Bit Error Rate) for DPSK (Differential Phase Shift Keying) and MSK (Minimum-Shift Keying) modulations for this distribution and higher moments of them, which is of great applicability to modeling wireless fading channels. Furthermore, a simple, not depending on any special function, apart of the Gamma function, bivariate version of the Nakagami-m distribution is also proposed as a special case of the multivariate version which is also presented. The proposed composite distribution is simulated through the standard procedure of summation of phasors, and results for the new closed-form measures for the MSK modulation are also shown. From that it is clear that the alternative formulation of the Nakagami-m distribution allows for easier modeling of fading fading-shadowing wireless channels through the new explicit second order statistics metrics. is well suited for modelling fading-shadowing wireless channels. [ABSTRACT FROM AUTHOR]

This paper describes the preparation and analysis of a new insulation composite material suitable for high-voltage applications. The material was characterized using Fourier transform infrared and X-ray diffraction spectroscopy, which revealed the presence of SiO2, confirming the successful integration of the matrix (polyester) and reinforcement material (celite filler). XRD also showed that the crystalline behavior of the composite changed as the proportion of epoxy and celite varied. Additionally, electrical characterization was conducted using ASTM D-149 and D-257, and it was found that an increase in the environmental temperature and humidity had a negative effect on the dielectric and resistivity properties of the composite. These results were both experimentally determined and theoretically verified by a one-dimensional finite element model. The results also showed that 5% celite composition is suitable for making ignition coil insulations, as it meets Indian and Japanese Industrial Standards. [ABSTRACT FROM AUTHOR]

With ever increasing environmental awareness, renewable raw materials for textile and composite industry have become an important alternative to reduce the use of petroleum-based non-biodegradable fibers in various applications such as marine, automotive, sports and aerospace. Therefore, it is highly critical to understand the chemistry, structure, and properties of novel plant fibers. Natural fibers have been used for various purposes since ancient times. Numerous research and review papers were published on harvesting, production, properties and potential applications of conventional natural fibers. Sustainability, renewability, and recyclability issues increased the use of novel natural fibers globally. New applications such as natural fiber reinforced biodegradable composites also increased the importance of investigations on new natural fibers. This review paper considers extraction methods, fiber structure, chemical, physical and mechanical properties of novel cellulosic fibers. Fiber chemical constituents, functional groups, and surface hydrophilicity were discussed in terms of chemical properties. Physical properties of the cellulosic fibers such as density, crystallinity, maximum thermal degradation, mechanical performance and surface morphology were also discussed. Additionally, mechanical performance of new plant fibers was performed by comparing between some properties of common and recently characterized cellulosic fibers. The brief information about life-cycle assessment, sustainability, recycling, and biocomposite application of the novel plant fibers is also presented. According to the best our knowledge on literature review, this review may be unique to provide detailed information about recently characterized cellulosic fibers. This survey will be helpful to researchers who have interest in novel ligno-cellulosic fibers and fiber reinforced composites. [ABSTRACT FROM AUTHOR]

As a directly net-shaped structure, 3D woven variable thickness composite plate is different from the constant thickness structure in terms of the changing weft yarn sizes and resulting various warp yarn direction. To investigate the mechanical behavior of this structure, a finite element (FE) model was proposed in this paper on the basis of author's previous geometric model illustrating the characterized details. Mesh convergence was studied to determine the size of element in compromise of accuracy and efficiency. Linear displacement rather than periodic boundary conditions were applied due to the thickness change. For the validation of presented FE model, a sample variable thickness plate in 3D layer to layer weave style was tested under tensile load in warp direction whose thickness was changed in this direction by the change of weft yarn size. The strain was monitored with the help of Digital Image Correlation (DIC) system. The results showed that the predicted homogenized stiffness in warp direction decreased with the thickness increasing, in agreement with the observation from experiments. The maximum error between the predicted stiffness and the measurements of typical segment (TS) in variable thickness region of the plate is 12.05 % while the minimum error is 0.7 %. [ABSTRACT FROM AUTHOR]

The paper proposes a two-dimensional thermokinetic model of the composite synthesis process in the mode of dynamic thermal explosion taking into account the structurization of the synthesis product. Structurization in the model is understood as a transition from amorphous to crystalline state. The model takes into account the heating of the reactor walls by thermal radiation from the device, the temperature of which can vary at different rates. Chemical reactions are described by a summary scheme that corresponds to the synthesis of Ni3Al composite. The kinetic law takes into account a possible strong inhibition of the rate of the reaction with the accumulation of the synthesis product, which is typical for reactions controlled by diffusion at the particle level. The effective thermophysical properties of the components of mixture and reaction products in the reactor depend on the properties of the constituents of the initial mixture and the fraction of reaction product. The properties of the latter also depend on the degree of structurization. The structurization process is described by a special additional parameter whose evolution is modeled by a reversible reaction. It is assumed that the structurization process starts from the moment of product appearance and continues during the cooling of the system. It is shown that synthesis results in the formation of a composite containing the initial components and the reaction product with the matrix partly in the amorphous state and partly in the structured state. The dynamics of synthesis and structurization are influenced by heating conditions and reactor size. [ABSTRACT FROM AUTHOR]

Inspired by nature, various biomimetic materials have been synthesized for enhanced mechanical properties, among which composites with brick-and-mortar structures attract the most attention. In such bio-inspired composites, the matrix layer mainly functions to transfer load between bricks through shearing, while the shear stress in the matrix is not uniform but highly concentrated on the interface ends, which tends to initiate cracks and evoke interface delamination in composites. To enhance the composites’ resistance to interface delamination, we propose to homogenize the shear stress by adopting a matrix with a gradient modulus. A theoretical solution to the optimal gradient modulus of the matrix layer is obtained, followed by computational validations. Moreover, composites with such functionally graded matrices are further demonstrated to possess higher elastic limits, higher resilience, and flaw tolerance than the uniform controls. The results of this paper should be of great value to the design and synthesis of advanced structural materials for superior mechanical performance. [ABSTRACT FROM AUTHOR]

Composite materials are very attracting in both aerospace and automotive applications because of their exceptional strength, stiffness-to-density ratio, and superior physical properties. However, these materials are susceptible to damage, necessitating effective repair techniques to maintain their structural integrity and extend their operational life. Due to the high production costs for every single component in carbo-resin, further repair techniques have been developed to repair damaged components of a complex structure on site without having to disassemble any element. In this scenario, the scope of this research paper is to implement an innovative repair procedure to be carried out on-site. The hot bonding process was used for the scope, and two different technologies involving both the prepreg and the dry patches impregned on site (infused) were proposed. Firstly, the composite panels were manufactured, and then they were analysed through non destroying evaluation techniques. The mechanical behaviour of the samples (under both the pristine and the repaired conditions) was evaluated through open hole tensile and compression tests aiming to assess their properties under maximum stress conditions. Impact tests at penetration and at indentation were conducted to study the performances under dynamic loading. Despite an increase of voids percentage was proved for the dry patches impregned panels (+ 33%), better mechanical properties were found for the infused specimens compared to prepregs (+ 8% and + 10% under compression and tensile loads, respectively), proving the effectiveness of the developed process. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach using Generative Adversarial Networks (GANs) to predict thermal stress distribution in binary composites. The composite plates, generated randomly, serve as the basis for finite element simulations that produce datasets for training the GANs. To enhance the training process, binary images representing composite architecture are combined with corresponding thermal stress distribution images, creating a unified dataset. Remarkably, the trained GANs exhibit a high level of accuracy in predicting thermal stress within the composites. The results underscore the potential of GANs in accurately predicting thermal stress, opening avenues for advancements in materials science. [ABSTRACT FROM AUTHOR]

This paper presents a groundbreaking strategy for optimizing composite laminate structures by integrating finite element modeling with a specialized multi-layer neural network. The neural network is trained on precise ground truth data obtained from rigorous finite element simulations, allowing it to discern intricate correlations among layer orientations, boundary conditions, and optimized designs. Tailored to the nuances of laminar composite optimization, the developed neural network emerges as a potent predictive tool, providing deep insights into the intricate interdependencies of design parameters. The study's findings hold immense promise for advancing materials design and structural engineering, highlighting the transformative potential of combining computational intelligence with traditional modeling approaches. [ABSTRACT FROM AUTHOR]

The paper investigates the normal interaction between the steel striker, carbon fiber and aramid fiber reinforced plastic plates at a speed ranging from 166.6 to 184.2 m/s. A series of physical and numerical experiments with impact load is conducted to design a mathematical model and numerical algorithm for the composite plate. The behavior and fracture of composites are described by the elastic-brittle model accounting for their different compressive and tensile strengths. The numerical simulation utilizes the finite element method in the EFES software developed by the authors. [ABSTRACT FROM AUTHOR]

The paper presents the results from studies of the electrical and magnetic properties of an inhomogeneous percolated medium based on the theory of percolation. The application of this theory has a wide and varied range. Examples include hopping conductivity in semiconductors, properties of porous materials, etc. It was found that, with approaching the percolation threshold pc = 0.35, the resistivity decreases, and the electrical conductivity increases accordingly. An increasing number of individual ferromagnetic nanogranules in (p)–Fe2O3–(1–p) (MBT) composites merge with the formation of individual Fe2O3 clusters in the bentonite matrix, which combine to form a continuous network of clusters. This is due to the fact that the resistivity ρ of the composite is mainly determined by the magnetic component of the latter. [ABSTRACT FROM AUTHOR]

There is a significant need for tools to detect damage in composite materials, whether for the development of models, the characterization of materials or the validation of structures. However, many different methods are available, each with its own advantages and drawbacks, making the choice difficult when setting up tests. This paper will present multi-instrumented uni-axial tests on [02,902]s carbon-epoxy samples at 0∘, 90∘ and 45∘. These tests feature DIC, thermography and acoustic measurements with a standard microphone in order to explore the capabilities of each of these methods. The processing is detailed and the information extracted from each method will be discussed in order to provide an overview of the uses for each method. [ABSTRACT FROM AUTHOR]

In this paper, we report an improved solid-state synthesis of Na3V2(PO4)3 isostructural with the NASICON superionic conductor and ranging in particle size from 0.5 to 4.5 μm with the use of spray drying of an aqueous solution of precursors, followed by annealing in a nitrogen atmosphere. The specific capacity of a composite of the synthesized Na3V2(PO4)3 and expanded graphite reaches 117.00 mAh/g at a charge–discharge rate of C/20 and drops to 76.73 mAh/g after 200 cycles in charge–discharge life tests at a charge–discharge rate of 1C. The apparent diffusion coefficient of sodium ions in the solid phase of the Na3V2(PO4)3/C composite for deintercalation and intercalation processes is 5.87 × 10–11 and 4.60 × 10–11 cm2/s, respectively. [ABSTRACT FROM AUTHOR]

The paper describes a specifically developed novel samarium cobaltate/silicon carbide composite that transforms into a high-performance carbon-resistant catalyst for dry reforming of methane into syngas (DRM). This 30%SmCoO3/70%SiC composite without hydrogen prereduction was tested in DRM at atmospheric pressure and GHSV 15 L g–1 h–1 (of an equimolar CH4–CO2 mixture). During the test, the yields of hydrogen and carbon monoxide reached 92 and 91 mol %, respectively, at 900°C, and 20 and 28 mol % at 700°C. Using XRD, TGA, and SEM examination, zero carbonization of the catalyst surface was demonstrated. It was found that, in the course of DRM, the initial composite transformed into a material that contained silicon carbide, samarium silicate, and samarium oxide, as well as metallic cobalt nanoparticles (<20 nm). [ABSTRACT FROM AUTHOR]

The paper presents an adsorption study of granular and composite adsorbents together with an analysis of the obtained images of the adsorbent surfaces. Based on the desiccator method of studying adsorbents, adsorption isotherms were plotted. According to these isotherms, active aluminum oxide was established as optimum for the manufacture of composite adsorption materials. However, the adsorption capacity of composite materials is less than that of granular adsorbents by 10–15%, which is compensated by higher density values. [ABSTRACT FROM AUTHOR]

Every year, a massive volume of textile waste is disposed of in a landfill or incinerated, contributing to resource loss and environmental consequences. Researchers are using textile waste to simultaneously develop composite materials to address both issues. Although manufacturing composites temporarily solves the problem, these composites will eventually wind up in landfills at the end of their service life unless appropriate manufacturing and recycling methods are followed. This review assessed the feasibility, benefits, drawbacks, and limitations of various composites manufactured from textile waste and their recycling procedures in terms of having minimal or no environmental impact after their end-of-life. This paper discusses two alternative composite manufacturing technologies and various recycling processes. Based on the review, developing biocomposites from textile waste comprised of natural components is one of the most promising options regarding sustainability and environmental friendliness. Moreover, by adopting this method, some partially biodegradable composites can be transformed into fully biodegradable materials, resulting in various benefits, including improved mechanical properties. Then, as one of the potential solutions, ionic liquids are discussed. Ionic liquids can dissolve a wide range of fibers. Most crucially, ionic liquids can dissolve a specific fiber from a blend of fibers, which is traditionally considered the main difficulty with textile waste. Furthermore, for some fully non-biodegradable and partially biodegradable composites, several recycling strategies have been discussed and, in part, used by numerous companies to recover waste fibers and keep them out of landfills. The advantages, downsides, and limitations of each recycling process have also been explored. Finally, applications and future perspectives for these manufacturing and recycling processes are emphasized. [ABSTRACT FROM AUTHOR]

Biomechanical study of brain injuries originated from mechanical damages to white matter tissue requires detailed information on mechanical characteristics of its main components, the axonal fibers and extracellular matrix, which is very limited due to practical difficulties of direct measurement. In this paper, a new theoretical framework was established based on microstructural modeling of brain white matter tissue as a soft composite for bidirectional hyperelastic characterization of its main components. First the tissue was modeled as an Ogden hyperelastic material, and its principal Cauchy stresses were formulated in the axonal and transverse directions under uniaxial and equibiaxial tension using the theory of homogenization. Upon fitting these formulae to the corresponding experimental test data, direction-dependent hyperelastic constants of the tissue were obtained. These directional properties then were used to estimate the strain energy stored in the homogenized model under each loading scenario. A new microstructural composite model of the tissue was also established using principles of composites micromechanics, in which the axonal fibers and surrounding matrix are modeled as different Ogden hyperelastic materials with unknown constants. Upon balancing the strain energies stored in the homogenized and composite models under different loading scenarios, fully coupled nonlinear equations as functions of unknown hyperelastic constants were derived, and their optimum solutions were found in a multi-parametric multi-objective optimization procedure using the response surface methodology. Finally, these solutions were implemented, in a bottom-up approach, into a micromechanical finite element model to reproduce the tissue responses under the same loadings and predict the tissue responses under unseen non-equibiaxial loadings. Results demonstrated a very good agreement between the model predictions and experimental results in both directions under different loadings. Moreover, the axonal fibers with hyperelastic characteristics stiffer than the extracellular matrix were shown to play the dominant role in directional reinforcement of the tissue. [ABSTRACT FROM AUTHOR]

Thick-walled composite pipes made of fibre reinforced laminate are good candidates to replace traditional metal counterparts in fabricating such as drive shafts and drilling pipes. In this paper, the behaviour of thick-walled composite pipes subjected to torsion load is considered. The developed finite elements model and three-dimensional elasticity solution are presented to analyse the stress state of the pipe. The modified Tsai-Hill failure criterion is adapted for the stress analysis. The distribution of failure coefficients through the pipe thickness for different lay-ups is calculated. The parametric study is carried out to investigate the effects of fibre orientations, stacking sequences, layer thicknesses and the magnitudes of torsion on the pipe performance. The torsional response shows sensitivity to changes in winding angle. Although 45° reinforcement angle provides the highest torsional stiffness, the results indicate that it is not always the optimal solution due to the torsional strength. For multi-layered composite pipes, the optimum solution for the winding angle depends on the configurations and the stacking sequences. Finally, a new approach for pipe lay-up design to withstand the applied load is suggested, introducing 'safety zones', which represents reasonable fibre orientation to resist torsion load. [ABSTRACT FROM AUTHOR]

Cellulose is one of the most abundant and sustainable biopolymers on earth. Various types of cellulosic materials such as natural fibres, regenerated cellulose fibres, cellulose derivatives and nanocellulose have increasingly been utilised in developing fibre-reinforced polymeric composites. Analysis of surface physicochemical properties of cellulose-based fillers is essential to maximise fibre-matrix interfacial adhesion to obtain excellent mechanical performance. Among different techniques which can be used to investigate the surface science of cellulose-based materials, inverse gas chromatography (IGC) has been proven as a successful technique for characterising the surface activity, evaluating the efficiency of surface modification methods, and predicting the behaviour of final products. IGC is a versatile approach to evaluate surface energy, acidic-basic characteristics, and surface heterogeneity. These key parameters are used in (i) evaluating the efficiency of different surface treatments for adding new functional groups, (ii) determining the compatibility of cellulosic materials with various polymer matrices to ensure optimal fibre-matrix interaction, and (iii) predicting the performance of cellulose-reinforced composites in actual applications. This article provides a concise review on recent progress in using IGC method for surface analysis of different forms of cellulosic materials in the context of fibre-reinforced composites. For future perspective, the IGC technique can be extensively applied in studying cellulosic materials with high application potential in a variety of fields. This review paper will shed light on understanding the surface characteristics of cellulose-based composites and pave the way for their real-world applications. [ABSTRACT FROM AUTHOR]

Developing efficient and effective oil/water separation materials with both high treatment flux and rejection by a low cost and simple way have been the main goal pursued by researchers. In this paper, a porous metal foam (Ni foam plate and slice) with high strength is selected as the substrate and bacterial nanocellulose fiber (BNC) is used as hydrophilic fibers for modification. Driven by concentration difference, we constructed Ni foam/BNC composite, where the BNC fibers could insert into the foam body and regulate the pore size of foam by only changing the fiber content. This enables the intrinsic large pores of the pristine Ni foam to decrease quickly while maintaining high porosity. Compared to the thick Ni foam plate, the stacks composed of thin Ni foam slices with various pore sizes can effectively separate different oil/water mixtures (i.e. layered oil/water mixtures, oil/water emulsions with and without surfactant) solely by gravity with high treatment flux and satisfactory oil rejection. Furthermore, the modified Ni foams show good reusability only through ethanol washing. The modified Ni foams could be used in the situations with severe water impact and large pressure difference owing to their high compressive modulus. It is expected that this facile pore size adjustment technology can provide us an easy scaled up method to construct filtering materials with high strength and oil/water separation efficiency. [ABSTRACT FROM AUTHOR]

This paper presents a new discontinuous damage model based on the interface thick level set method for modeling the fiber bridging effects on fatigue delaminaton propagation in composites. To incorporate the bridging effects under fatigue loading a modified Paris relation proposed in Yao (Compos Struct 176:556–564, 2017) is employed in developed model. This requires to define the fracture energy as a function of the crack length which is computed using the level set method. The proposed 3D model is validated against experimental and theoretical data which proves the accuracy of obtained results. [ABSTRACT FROM AUTHOR]

Tensile stress–strain testing and creep testing have been carried out on a polyurethane rubber, at three temperatures, with and without either particulate or short fibre alumina reinforcement. A previous paper reported concerning composites with particulate reinforcement and the present work is focused on the effect of the fibres. The samples were made via a blending and extrusion process that produced a certain degree of fibre alignment (along the direction of loading). Prior milling procedures were used to produce fibres with two different ranges of aspect ratio (with averages about 10 and 16). When expressed as true stress–strain relationships, all materials exhibit approximately linear responses. The dependence of stiffness on the volume fraction and aspect ratio of the reinforcement was found to conform well to the Eshelby model predictions. Moreover, the creep behaviour of all of the materials can be captured well by a Miller–Norton formulation, using the average matrix stress predicted by the Eshelby model. A striking conclusion is that it is both predicted and observed that short fibres are much more effective in reducing the creep rate than is the case with particles. [ABSTRACT FROM AUTHOR]

This paper presents the results of numerical simulation of the interaction of cylindrical steel projectiles with orthotropic organoplastic barriers. Problems are solved numerically, by the finite element method, in a threedimensional formulation within the framework of the phenomenological approach to solid mechanics using the original EFES software package. The behavior of the steel projectile material is described by an elastic model. The behavior of the anisotropic material is represented by an elastic-brittle model. The effect of failure criteria on the stress-strain state of the anisotropic barrier is compared. [ABSTRACT FROM AUTHOR]

Hexagonal boron nitride nanosheets (BNNS) and their photosensitive resin-based composites have excellent thermal conductivity, thermal stability, and electrical properties, making them promising applications in electronic devices and packaging. In this paper, BNNS were exfoliated by hydrothermal method, and BNNS/photosensitive resin composite was prepared by ultraviolet curing. The enhancement effect of BNNS on the thermal stability and electrical properties of the composites was studied. The result showed that few-layer BNNS with hexagonal structure were obtained after hydrothermal exfoliation of hexagonal boron nitride (h-BN), part of the B–N bond in BNNS formed a covalent bond with the photosensitive resin matrix. Both of chemical interface and overlapping interface formed between BNNS and the matrix help to form a better and tighter interface, which effectively improves the thermal stability of the photosensitive resin. As the mass percentage of BNNS increases, the temperature required for the decomposition of BNNS/photosensitive resin composites increases, and the relative permittivity also increases significantly because of the interface polarization. When the content of BNNS reaches 10 wt%, it reaches the highest value of 7.623 at the frequency of 1 kHz. Due to the high surface area of the few-layer BNNS, a network structure is formed in the matrix, which improves the breakdown strength of the photosensitive resin. [ABSTRACT FROM AUTHOR]

The objective of this paper was to obtain safe composite drive shaft having enough higher performance with less weight over steel one. For this purpose, finite element analysis FEA for five cases of different stacking sequence for composite drive shaft is carried out. Stacking sequence for these five cases is as the following case 1: [+ 45°/− 45°]8, case 2: [+ 45°/− 45°/+ 45°/− 45°/+ 45°/− 45°/0°/0°]2, case 3: [0°/0°/+ 45°/− 45°/+ 45°/− 45°/+ 45°/− 45°]2, case 4: [+ 45°/− 45°/+ 45°/− 45°/+ 45°/− 45°/90°/90°]2 and case 5: [+ 45°/− 45°/+ 45°/− 45°/+ 45°/− 45°/90°/0°]2. FEA results for these five cases are compared, and the comparison showed that cases 4 and 5 are optimum stacking sequence for composite drive shaft. FEA results for these two cases are compared with those of conventional steel drive shaft. The results showed that the composite drive shaft satisfies Tsai–Wu strength failure criteria with smooth operating where it has much higher safety in von misses stress and higher of critical speed and torsional buckling frequencies with weight saving 78.7% over conventional steel drive shaft. [ABSTRACT FROM AUTHOR]

Graphite-like carbon nitride (g-C3N4) has attracted wide attention in the field of photocatalysis due to its simple and feasible preparation method and appropriate energy gap structure for light absorption in a wide range. However, its high recombination rate of photo-generated electrons and holes affects its catalytic efficiency. In this paper, type II strontium titanate/graphite-like carbon nitride (SrTiO3/g-C3N4) heterojunction photocatalysts were designed and prepared by mixed calcination method. The results of XRD and IR spectra have showed that the two semiconductors were well combined. The wider light absorption range was found in the 10 wt % SrTiO3 composite materials by UV–Vis diffuse reflection spectrum, and it was proved that the recombination of photo-generated electrons and holes was greatly reduced by PL spectrum and photoelectric tests. The photocatalytic degradation ratio of 10 wt %–SrTiO3/g-C3N4 composite materials was about 56 times higher than that of pure g-C3N4 by degrading tetracycline drugs (TCN), and the performance of photocatalytic degradation of TCN still remained at about 96.4% after five cycles. The photocatalytic mechanism analysis indicates that the type-II heterojunction photocatalysts are formed between SrTiO3 and g-C3N4 composite materials, and the reasons for improving photocatalytic degradation efficiency of TCN are explained. [ABSTRACT FROM AUTHOR]