Selection Of Composite Materials Research Articles

A systematic framework for the design and material selection of composite for tennis racket upon impact

The present study explores the comprehensive composite material selection methodology of a tennis racket involving coupled Multi-Criteria Decision-Making (MCDM) and numerical analysis. Initially all the possible material alternatives from the composite family were shortlisted using CES Selector 2016. A design space was developed incorporating MCDM technique naming VICKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje), PROMETHEE (Preference Ranking Organisation Method for Enrichment Evaluation) and TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) to rank the most suitable composite material based on critical mechanical properties to identify the most suitable composite materials for applications requiring optimal combinations of rigidity, strength, and structural performance. Using finite element analysis, the structural integrity of each of the materials was evaluated on static and dynamic stress analysis modules of ANSYS. Out of all material alternatives, T300 carbon fiber epoxy was considered as the most suitable for tennis rackets. Further, a comparison between the selected material was also made with conventional materials and were found in good agreement with selected material.

A behavior three-way decision approach under interval-valued triangular fuzzy numbers with application to the selection of additive manufacturing composites

Additive manufacturing composites, also recognized as three-dimensional (3D) printing composites, are highly anticipated for their potential to replace industrial materials due to the availability of multiple printing processes and optional materials. However, research gaps exist in cognitive deficiencies and psychological behaviors of decision-makers, as well as experimental error effects caused by material testing, resulting in material selection as a challenging issue. Therefore, this study proposes a novel behavior three-way decision model under the interval-valued triangular fuzzy number (IVTFN) to settle the selection issue of 3D printing composites. The research contributions are summarized as follows. First, the IVTFN is presented to account for the impacts of cognitive deficiency and experimental errors, based on which the concepts of information entropy and fuzzy measure are further developed to conduct the criterion weights. In addition, by integrating the prospect theory and regret theory, a framework for constructing the behavioral decision matrix is presented. Moreover, a novel behavior three-way decision model with the perspectives of objective and preference is proposed to classify the decision region. This study presents a comprehensive methodology integrating the three-way decision model and multi-criteria decision-making method to achieve both alternative ranking and alternative classifying. Finally, a research case of 3D printing composites reinforced by continuous hybrid fibers is adopted to illustrate the validity of the methodology. Comparative analysis and sensitivity analysis are also performed. This study offers valuable insights and tools for systematically tackling the 3D printing composite material selection issues.

Selection of sustainable construction material from recycled waste plastics by q-rung orthopair fuzzy SWARA-MABAC approach

Recycling of waste plastics and agro-industrial waste for the development of sustainable polymeric composites is recognized as a viable approach to overcome the detrimental environmental effects of plastics waste. Despite of immense potential of sustainable composites in the Circular Economy (CE), its implementation is still insignificant due to the lack of an effective material selection approach. The existence of several influencing aspects in the process of material selection considers it a multi-criteria decision making (MCDM) problem. In the present work, an Aggregation Operator (AO) based integrated Stepwise Weight Assessment Ratio Analysis (SWARA) and Multi-attributive Border Approximation Area Comparison (MABAC) has been proposed to deal with the issues of material selection for polymer based sustainable composites. Moreover, q-rung orthopair fuzzy numbers (q-ROPFNs) have been implemented to tackle the uncertainty in the information. The effectiveness of the proposed approach has been confirmed by different comparative and sensitivity investigations. The developed composites have shown excellent properties whereas the responses of the materials vary invariably with compositions. The proposed method has identified the amalgamation of 10 wt percentage of rice husk ash and 10 wt percentage of sand with 80 wt percentage of high-density polyethylene (HDPE) as an appropriate material for the development of sustainable floor tiles as the composites resulted to optimum mechanical performances and minimum abrasive wear. The proposed model gives reliable and robust results and is sensitive to the criteria weights and mathematical parameters. The outcome of the research has exposed that the suggested mathematical approach can be effectively applied for material selection of sustainable polymeric composites for different applications.

Novel computational model for the failure analysis of composite pipes under bending

This study presents a novel computational model to investigate the bending behaviour of thin- and thick-walled composite pipes made from fully bonded fibre-reinforced thermoplastic composite materials. The primary objective is to analyse the stress state and predict potential failure modes of these pipes, which have gained significant interest in the oil and gas industry due to their advantageous properties. The developed model is validated through comparisons with finite element analysis and published results, demonstrating its accuracy and adaptability. Utilising the validated computational model, safety zones for composite pipes with various stacking sequences are established, providing valuable insights into the optimal design of composite pipes under bending loads. Furthermore, the method is employed to determine the maximum bending moment and critical bendable radius of the pipe, revealing the direct correlation between maximum bending moment and bending stiffness, independent of the bending radius. The findings of this study offer practical guidance for the design and optimisation of composite pipes in the oil and gas industry, promoting their adoption as a viable alternative to traditional metal pipes. The developed computational model serves as an efficient and reliable tool for engineers to make informed decisions in the design and selection of advanced composite materials for pipe applications, enabling the optimisation of pipe performance under various bending load scenarios.

Analysis and selection of composite material for the manufacture of products during the design preparation stage

Analysis and selection of composite material for the manufacture of products during the design preparation stage

The multi-objective optimization of material properties of 3D print onyx/carbon fiber composites via surrogate model

Composite materials play a prominent role in modern engineering. The emergence of composite material technology has brought about a profound impact on almost, if not all industries. The aerospace industry, for instance, benefits greatly from composite materials. With composites, aircraft weight can be reduced while the structural strength is maintained. As with other classes of materials, 3D printing technique allows composite parts of high complexity to be fabricated with great precision. Additionally, with 3D printing, mechanical properties of the resulted part can be accurately customized and controlled by means of varying matrix-reinforcement proportions. As the composite material can be indefinitely customized in 3D printing, it is crucial to evaluate the mechanical properties of the printed specimen. While testing of printed specimens is usually possible, endless production and testing of specimens not only takes time and resources but also leads to extensive experimental waste. In this study, an optimization-based technique is proposed to determine the optimal 3D printing material proportion in order to reduce the need of unwarranted experimental waste and improve the efficiency of composite material selection process. The study aims to investigate the properties of Onyx/Carbon fiber composite material and the optimization of the 3D printing configuration to achieve desirable mechanical properties. The effects of the number of carbon concentric fiber rings and the percentage of infill density of Onyx used in 3D printing were examined. ASTM D3039 tensile tests were performed to obtain mechanical properties of the printed specimen. Considering the values of tensile strength and modulus of elasticity of the printed material, the printing configurations were optimized using a multi-objective non-dominated sorting genetic algorithm II (NSGA-II) with the Kriging model for objective function estimation. From the proposed optimization technique, it has been found that the maximum tensile strength is attained when the number of concentric fiber rings is equal to 3 while the percentage of Onyx infill density falls in the range of 86–90. Contrarily, the modulus of elasticity is maximized when the number of concentric fiber rings is equal to 4 with the percentage of Onyx infill density in the range of 70–75.

Toward esthetically and biomechanically reliable anterior resin composite restorations: Current clinical experiences among dental practitioners in Saudi Arabia.

Background: Esthetic anterior composite restorations are very challenging. They constitute a main part of the clinical practice of restoring teeth with resin composites. Distinctive variations in composite material selection and technique of application in anterior teeth exist when compared to the practice of restoring posterior teeth with resin composites. In a continuation of a previous assessment of class II resin composite practice, a cross-sectional survey study was performed to determine the awareness of general dental practitioners in Saudi Arabia about resin composite restorations in anterior teeth and to provide evidence-based recommendations to improve their practice. Methods: A total of 500 dental practitioners from different provinces in Saudi Arabia were invited to participate in an online questionnaire which comprised four domains and included a total of sixteen questions addressing aspects regarding the selection of resin composites, cavity configuration, etching protocol, light-curing technique, liner application, application of poly-chromatic composite, as well as finishing and polishing procedures. Chi square testing and descriptive statistics were used to analyze the attained data. Results: From 250 respondents, the greatest participation was from the Eastern and Middle provinces of Saudi Arabia. Female dentists participated less than males. There was no general agreement between participants regarding the resin composite material or the employed technique of application in restoring anterior tooth defects. Respondents indicated that discoloration and hypersensitivity were the most common reasons for patient's dissatisfaction with resin composites in anterior teeth. Conclusions: Dental practitioners are highly encouraged to improve their clinical practice of restoring anterior teeth using resin composites with the focus upon continuous education programs, online webinars, and workshops.

Selection and ranking of dental restorative composite materials using hybrid Entropy-VIKOR method: An application of MCDM technique

The objective of this investigation was to design the selection and ranking of dental restorative composite materials using hybrid Entropy-VIKOR as the MCDM method. Eleven performance defining attributes (PDAs) of dental composites were considered to investigate the best formulation among the dental composites. The weight criteria of various PDAs of the dental composite were calculated by the Entropy method: PDA-1(0.0527), PDA-2 (0.0113), PDA-3(0.1692), PDA-4(0.1291), PDA-5(0.0207), etc. The VIKOR method was employed to demonstrate the rank of dental composites. As per the VIKOR method, the first rank was obtained by DHZ6, the second rank was by DHZ8, the third rank was by DHZ4, the fourth rank was by DHZ2, and the lowest rank was by DHZ0. The Hybrid Entropy-VIKOR method holds significance in the biomedical realm due to its capability to effectively address complex decision-making scenarios. Its ability to account for multiple criteria, uncertainties, and compromise solutions makes it particularly useful for enhancing decision-making processes in the biomedical field, where selecting the most suitable options is critical for patient outcomes and healthcare advancements.

A hybrid multi-stage decision-making method with probabilistic interval-valued hesitant fuzzy set for 3D printed composite material selection

The 3D printed composite material selection is of great interest due to its extensive application prospect and can be considered as a challenging multiple-criteria decision making (MCDM) issue. The hesitation and uncertainty of experts are difficult to measure, and the high degree of interaction among criteria is often overlooked in the decision process. In addition, composites are required to serve in harsh environments for various mechanical and industrial fields, resulting in the degradation of mechanical properties. In this study, a hybrid multi-stage decision-making method is developed to conduct 3D printed composite material selection in harsh environments. The theory of probabilistic interval-valued hesitant fuzzy set (PIVHFS) is proposed to characterize the decision-making information of experts, which can effectively quantify the assessment in uncertain environments. An integrated method that combines Choquet fuzzy integral and Shapley value is proposed to obtain the weight vector of criteria, which can reflect the mutual influence between criteria and their overall importance. The final decision-making result and the optimal alternative can be calculated by the PIVHFS-based Tomada de Decisão Interativa Multicritério and Technique for order preference by similarity to an ideal solution (TODIM-TOPSIS) method. An empirical application, i.e., 3D printed composites in the background of automotive chassis, is applied to validate the application of the proposed method. Comparative analysis, sensitivity analysis, and managerial implications are also conducted to illustrate the validity of the method. This paper provides a valuable tool for addressing the material selection issue of 3D printed composites from a multi-criteria perspective.

Material selection of sustainable composites by recycling of waste plastics and agro-industrial waste for structural applications: A fuzzy group decision-making approach

Recycling of waste plastics (WP) for the development of sustainable composite materials is one of the effective methods to deal with the problems of the generated plastics wastes. The research proposes an integrated Analytical Hierarchy Process-Techniques for Order Preference by Similarity to Ideal Solution (AHP-TOPSIS) approach based on triangular fuzzy weighted Bonferroni mean operator (TFWBMO) for the selection of an appropriate composition for development of floor tiles by recycling WP and agro-industrial wastes. The decision hierarchy has been formed by collecting the experts' opinion from five different academicians and personalities engaged in the domain of sustainable composites. The present work suggests that the amalgamation of 90 wt % of low-density polyethylene with 10 wt % of fillers is a suitable composition for structural applications. The comparative analyses of the results with well-known techniques and sensitivity analyses have confirmed the reliability of the proposed model. Moreover, Spearman's rank correlation coefficient (SRCC) has verified the statistical consistency of the proposed model. The proposed mathematical model is efficient in handling the vagueness in decision-making and hence can be successfully implemented to overcome the issues of material selection in large scale production of sustainable structural materials. The research has explored the potential of WP in the replacements of the conventional structural materials by a sustainable composites possessing expedient features.

Toward esthetically and biomechanically reliable anterior resin composite restorations: Current clinical experiences among dental practitioners in Saudi Arabia

Background: Esthetic anterior composite restorations are very challenging. They constitute a main part of the clinical practice of restoring teeth with resin composites. Distinctive variations in composite material selection and technique of application in anterior teeth exist when compared to the practice of restoring posterior teeth with resin composites. In a continuation of a previous assessment of class II resin composite practice, a cross-sectional survey study was performed to determine the awareness of general dental practitioners in Saudi Arabia about resin composite restorations in anterior teeth and to provide evidence-based recommendations to improve their practice. Methods: A total of 500 dental practitioners from different provinces in Saudi Arabia were invited to participate in an online questionnaire which comprised four domains and included a total of sixteen questions addressing aspects regarding the selection of resin composites, cavity configuration, etching protocol, light-curing technique, liner application, application of poly-chromatic composite, as well as finishing and polishing procedures. Chi square testing and descriptive statistics were used to analyze the attained data. Results: From 250 respondents, the greatest participation was from the Eastern and Middle provinces of Saudi Arabia. Female dentists participated less than males. There was no general agreement between participants regarding the resin composite material or the employed technique of application in restoring anterior tooth defects. Respondents indicated that discoloration and hypersensitivity were the most common reasons for patient’s dissatisfaction with resin composites in anterior teeth. Conclusions: Dental practitioners are highly encouraged to improve their clinical practice of restoring anterior teeth using resin composites with the focus upon continuous education programs, online webinars, and workshops.

ТЕХНОЛОГІЯ СТВОРЕННЯ ЕЛЕМЕНТІВ БЕЗПІЛОТНИХ ЛІТАЛЬНИХ АПАРАТІВ ЗА АДИТИВНИМИ ТЕХНОЛОГІЯМИ

The article describes the technology of building elements of unmanned aerial vehicles (UAV) based on the use of additive technologies (AT). AT opened a fundamentally new direction in the concept of UAV manufacturing, which makes it possible to obtain a final product of a given shape and size based on a digital prototype. The modern equipment used in JSC is constantly being improved and allows for high printing speeds to increase the quality of the product at relatively low costs. The use of AT makes it possible to significantly reduce the weight of UAV elements due to the reduction of material costs. The article examines the technological process of 3D printing of UAV elements and the technological scheme of materials selection for the manufacture of UAV elements. In the course of the conducted research, a number of problems related to the need to improve the process of 3D printing of complex elements of UAVs, in order to effectively use the latest additive 3D printing technologies in modern production in combat conditions, were identified. The results of test printing, plastic tests and calculations made it possible to develop a general methodology for the production of UAV elements using additive technologies. The introduction of additive technologies for the production of UAV elements in the field will contribute to solving a wide range of combat tasks. It has been established that the use of additive technologies will entail the adjustment of UAV design principles, the development of printing technologies, the use of new construction strategies, the emergence of new technologies related to 3D printing. The analysis of quality control mechanisms for the development of UAV elements shows that the technological scheme for the selection of composite material is an important element in the 3D printing of modern UAVs and their components. It was determined that with the improvement of technological equipment and the development of methods of material selection for the manufacture of UAV elements, the direction of creating new UAVs with the help of AT will steadily expand. Keywords: additive technologies, UAV, 3D printing, technology, structure.

Detection of Leachable Components from Conventional and Dental Bulk-Fill Resin Composites (High and Low Viscosity) Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) Method.

The aim of this study was to investigate leachable components (monomers) in high and low viscosity dental bulk-fill resin composites and conventional resin composite materials after polymerization. Six bulk-fill and six conventional dental resin composite materials were used in this study. The samples of each material (three sets of triplicates) were cured for 20 s with irradiance of 1200 mW/cm2 with a LED curing unit and immersed in a 75% ethanol solution at 37 °C. The eluates from each triplicate set were analyzed after 24 h, 7 days or 28 days using liquid chromatography coupled with triple quadrupole tandem mass spectrometry (LC-MS/MS). Detectable amounts of 2-Hydroxyethyl methacrylate (HEMA) were found in both Gradia materials and the amount observed across different time points was statistically different (p ˂ 0.05), with the amount in solution increasing for Gradia and decreasing for Gradia Direct flo. Bisphenol A diglycidildimethacrylate (BIS GMA) was found in Filtek and Tetric materials. Triethylene glycol dimethacrylate (TEGDMA) was detected in all materials. On the other hand, there were no statistically significant differences in the amounts of TEGDMA detected across different time points in either of the tested materials. Monomers HEMA, TEGDMA, 4-dimethylaminobenzoic acid ethyl ester (DMA BEE) and BIS GMA in bulk-fill and conventional composites (high and low viscosity) can be eluted after polymerization. The good selection of composite material and proper handling, the following of the manufacturer's instructions for polymerization and the use of finishing and polishing procedures may reduce the elution of the unpolymerized monomers> responsible for the possible allergic and genotoxic potential of dental resin composites.

Materials selection of 3D printed polyamide-based composites at different strain rates: A case study of automobile front bumpers

The selection of 3D printed composite materials considering multiple criteria has become a challenging issue for designers/engineers and can be regarded as a typical decision-making problem. Especially for diverse engineering applications, the different strain rates encountered need to be addressed in the decision-making process. In this study, a systematic hierarchical evaluation model of 3D printed polyamide-based composites with 27 indicators is established considering economic, environmental, social and mechanical aspects. The mechanical responses at four strain rates (8 × 10−4 s−1, 8 × 10−3 s−1, 1700 s−1 and 3510 s−1) are incorporated into the model. A hybrid decision-making approach combining the fuzzy DEMATEL (Decision Making Trial and Evaluation Laboratory)-Entropy and fuzzy TODIM (Tomada de Decisão Interativa Multicritério)-VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje) methods is proposed to solve the composite material selection problem. An automobile front bumper, as an empirical application, is investigated to demonstrate the proposed model and decision-making approach. The results show that PACF-C, that is the short carbon fibre reinforced polyamide printed with a concentric strategy, is the optimal alternative. This study provides an effective approach for solving the material selection problem of 3D printed composites.

Developing fire retardant composites of biodegradable polyethylene reinforced with agricultural wastes

Developing novel natural fiber thermoplastic composites is twofold effective. The Added-value of local agricultural wastes is enhanced and the environmental burden is reduced by less use of imported synthetic fibers and more recycling of agricultural waste. Material selection, parametric optimization, and characterization of biodegradable natural fiber thermoplastic composites with flame retardant properties are carried out in this work. Thermoplastic matrix is linear aliphatic low-density Polyethylene PE. [0–30 wt%] natural fibers of locally produced jute, corn silk, and Bagasse are used for reinforcing. Fibers are cut to different lengths after being alkali-treated. 16–24 % ammonium polyphosphate APP is used for fire retarding at different loadings. A coupling agent is added to link the polymer matrix with the fiber. 3% Ferric Stearate is used for biodegradability activation. The samples are produced using a compounding kneader at 180 °C. Mechanical, water absorption, and flame-retardant properties are characterized. The biodegradability index, which is an indication to what extent the products manufactured from the composite are eco-friendly, is being measured. Jute composites show the highest mechanical properties of 11 MPa ultimate strength and 8 GPa modulus of elasticity, whereas the corn silk composites have better performance of V-2 according to the UL94 flame retardancy test. Water absorption of 15% fiber content is reduced to 1%.

Estimation of dynamic characteristics of a wind turbine blade

Wind energy is considered a clean source of energy that can be used efficiently to produce electricity without any harmful emissions. A wind turbine is an electro-mechanical system that converts the wind's kinetic energy into electricity. A typical wind turbine consists of three components, viz. the rotor (which includes the turbine blades), generator and the supporting structure. The turbine blades are a critical component of any wind turbine. They comprise of numerous airfoil sections with varying chord lengths and twist angles, that are combined together to form a three-dimensional blade surface. When generating electrical power through rotating motion, they are subjected to different loads, such as wind, gravitational, and centrifugal loads. The sheer size of the turbine blade necessitates the use of light and strong materials, and composites are well suited for this. The selection and manufacturing of suitable composite material is critical to blade design as it directly affects the efficiency and power of wind power plants. With blades that are continuously exposed to large wind loads, it is essential to determine the natural frequencies of vibrations at which they occur and understand the consequences. Large amplitude vibrations can induce dynamic stresses and accelerate the fatigue of the blade material leading to blade breakage. Thus, it is of significant importance to analyse the dynamic behaviour of these structures. This study aims to investigate the effect of varying fiber orientation and volume fraction on natural frequencies and vibration modes of the turbine blade.

Electronic Structure and Adsorption Behavior of Non-Metallic Atoms and Aluminum Atoms on the Surface of Graphene: DFT Theoretical Calculation

Graphene has been widely studied in many fields due to its excellent physical and chemical properties. In this paper, we focus on the electronic structure and adsorption behavior of Al atoms and X ([Formula: see text], N, Si, S) atoms co-adsorption on the surface of pure graphene and Al atom adsorption on the surface of X ([Formula: see text], N, Si, S) atoms-doped graphene systematically. The adsorption energy, adsorption distance, bond length, bond angle, and electronic structure were studied using density functional theory (DFT) theoretical calculation. The results show that the adsorption capacity of (Al, X) atoms co-adsorbed on the graphene surface is significantly improved compared to the Al atoms on the pure graphene surface. The adsorption energy of Al and B atoms co-adsorbed on the graphene surface is basically the same as that of Al atoms on the B-doped graphene surface. The calculation results also show that the adsorption capacity of Al atoms and X ([Formula: see text], Si, S) atoms co-adsorbed on the surface of graphene is better than that of Al atoms on the surface of graphene doped with X (X = N, Si, S) atoms. Compared with N atom and S atom-doped systems, the Si-doped graphene surface has a stronger adsorption capacity for Al atoms than pure graphene. However, due to the doping of N and S atoms, the adsorption capacity of Al atoms on the graphene surface is somewhat reduced. Our calculation results provide a theoretical basis for further selection of Al-based graphene composite materials.

ПІДБІР МАТЕРІАЛУ ДЛЯ ВИГОТОВЛЕННЯ ЕЛЕМЕНТІВ БЕЗПІЛОТНИХ ЛІТАЛЬНИХ АПАРАТІВ ЗА АДИТИВНИМИ ТЕХНОЛОГІЯМИ

Additive technologies have made it possible to form a fundamentally new direction in the technology of unmanned aerial vehicles production, with the help of which it is possible to manufacture single and unique samples of products due to the layer-by-layer build-up of material by the method of layer-by-layer synthesis with the simultaneous obtaining of the given shape and dimensions of the next product based on a digital prototype. Modern capabilities of equipment and materials are rapidly evolving towards larger product sizes, higher accuracy and quality, high product printing speeds and low costs. When using traditional methods of production, the cost and complexity of unmanned aerial vehicles is quite high. The use of additive technologies allows you to significantly reduce the weight of the UAV body due to the reduction of material consumption. The article investigates the properties of various polymers used in additive manufacturing, determines their impact on the quality of unmanned aerial vehicles elements, and also develops a methodology for selecting materials for the manufacture of unmanned aerial vehicles elements. The conducted research revealed a whole layer of issues and problems related to the need to improve the 3D printing process, organization and management of the printing of complex elements of the air defense system, which would allow effective use of the latest additive 3D printing technologies in modern production in combat conditions. According to the results of the research, the properties of the main materials for 3D printing, which are used in the FDM technology of obtaining the product, have been established. It has been established that the use of additive technologies will entail the adjustment of unmanned aerial vehicles design principles, the development of printing technologies, the use of new construction strategies, and the emergence of new technologies related to 3D printing. The analysis of quality control mechanisms for the development of unmanned aerial vehicles elements shows that the technological scheme for the selection of composite material is an important element in the 3D printing of modern unmanned aerial vehicles and their components. It was determined that with the improvement of technological equipment and the development of methods of material selection for the manufacture of unmanned aerial vehicles elements, the direction of creating new unmanned aerial vehicles with the help of additive technologies will steadily expand. Keywords: additive technologies; unmanned aerial vehicles; 3D printing; polymer; structure.

Enhanced thermal energy storage performance of molten salt for the next generation concentrated solar power plants by SiO2 nanoparticles: A molecular dynamics study

Chloride molten salt is the most promising thermal energy storage materials for the next generation concentrated solar power (CSP) plants. In this work, to enhance the thermal performance of KNaCl2 molten salts, composited thermal energy storage (CTES) materials based on amorphous SiO2 nanoparticles and KNaCl2 were proposed and designed under the guidance of the material composition design strategy. The molecular dynamics simulation method has been conducted to investigate the thermal storage properties and analyze the mechanism of heat transfer improvement from the perspective of microstructure evolution, thermal diffusion properties and energy changes. Thermal conductivity, viscosity, and specific heat capacity of CTES materials at high temperatures with different volume fractions of nanoparticles were predicted to provide reference data for the design of heat transfer systems in CSP plants. The study discovered that increasing the volume fraction of nanoparticles increases the thermal conductivity and specific heat capacity of the systems significantly, with the maximum increase of 25.28% and 7.87%, respectively. Moreover, the enhancement of heat transfer characteristics is the result of the formation of a compressed interface layer with a thickness 5 Å on the outer surface of SiO2 nanoparticles. This work has important guiding significance for the material selection and composition design of molten salt-nanoparticle composite materials used for next-generation CSP plants.

The Influence of the Performance Parameters of Bimetal Composite Pipe on the Forming Efficiency

In order to solve the problem of low efficiency in the mechanical drawing process of bimetal composite pipe, a dynamic model of the forming process of bimetal composite pipe is established based on the principle of virtual work and the elastic-plastic deformation criterion. The influence of the material properties of the inner pipe and the outer pipe on the forming success rate is studied. The residual stress of the inner pipe and the outer pipe after forming is taken as the main evaluation object, and the elastic modulus and yield of the material are systematically analyzed The influence of strength on residual stress. The results show that the ratio of the elastic modulus of the inner tube to that of the outer tube is more than 0.6 times of the yield strength when the bimetal composite tube is formed, and the materials with large elastic modulus and small yield strength of the inner tube and small elastic modulus and large yield strength of the outer tube should be selected as far as possible. At last, the theory of material parameter proportion for the successful forming of inner tube and outer tube is put forward. The research conclusion is reasonable and universal, which provides a scientific basis for the selection of composite tube materials, and has engineering practical significance for improving the forming efficiency of bimetal composite tube.