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14 pages, 2783 KiB

Open AccessArticle

The Reaction Products of the Al–Nb–B₂O₃–CuO System in an Al 6063 Alloy Melt and Their Influence on the Alloy’s Structure and Characteristics

by Chenggong Zhang, Min Ao, Jingyu Zhai, Zhiming Shi and Huimin Liu

Materials 2022, 15(24), 8898; https://doi.org/10.3390/ma15248898 - 13 Dec 2022

Cited by 1 | Viewed by 1670

Abstract

To meet aero-engine aluminum skirt requirements, an experiment was carried out using Al–Nb–B₂O₃–CuO as the reaction system and a 6063 aluminum alloy melt as the reaction medium for a contact reaction, and 6063 aluminum matrix composites containing in situ [...] Read more.

To meet aero-engine aluminum skirt requirements, an experiment was carried out using Al–Nb–B₂O₃–CuO as the reaction system and a 6063 aluminum alloy melt as the reaction medium for a contact reaction, and 6063 aluminum matrix composites containing in situ particles were prepared with the near-liquid-phase line-casting method after the reaction was completed. The effects of the reactant molar ratio and the preheating temperature on the in situ reaction process and products were explored in order to determine the influence of in situ-reaction-product features on the organization and the qualities of the composites. Thermodynamic calculations, DSC analysis, and experiments revealed that the reaction could continue when the molar ratio of the reactants of Al–Nb–B₂O₃–CuO was 6:1:1:1.5. A kinetic study revealed that the Al thermal reaction in the system produced Al₂O₃ and [B], and the [B] atoms interacted with Nb to generate NbB₂. With increasing temperature, the interaction between the Nb and the AlB₂ produced hexagonal NbB₂ particles with an average longitudinal size of 1 μm and subspherical Al₂O₃ particles with an average longitudinal size of 0.2 μm. The microstructure of the composites was reasonably fine, with an estimated equiaxed crystal size of around 22 μm, a tensile strength of 170 MPa, a yield strength of 135 MPa, an elongation of 13.4%, and a fracture energy of 17.05 × 10⁵ KJ/m³, with a content of 2.3 wt% complex-phase particles. When compared to the matrix alloy without addition, the NbB₂ and Al₂O₃ particles produced by the in situ reaction had a significant refinement effect on the microstructure of the alloy, and the plasticity of the composite in the as-cast state was improved while maintaining higher strength and better overall mechanical properties, allowing for industrial mass production. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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14 pages, 3857 KiB

Open AccessEditor’s ChoiceArticle

Fatigue Evaluation for Innovative Excavator Arms Made of Composite Material

by Luigi Solazzi, Andrea Buffoli and Federico Ceresoli

Materials 2022, 15(21), 7480; https://doi.org/10.3390/ma15217480 - 25 Oct 2022

Cited by 1 | Viewed by 2235

Abstract

This research reports the results related to the evaluation of the fatigue phenomenon of the arms of a medium–large excavator made of composite material (carbon fiber) instead of the classic constructional steel S355 (UNI EN 10025-3). In the numerical sizing phase, it was [...] Read more.

This research reports the results related to the evaluation of the fatigue phenomenon of the arms of a medium–large excavator made of composite material (carbon fiber) instead of the classic constructional steel S355 (UNI EN 10025-3). In the numerical sizing phase, it was obtained that the overall weight of the excavator’s arms made of composite material is about 35% of the same components made of steel, obviously with equal performance in terms of the safety static coefficient, rigidity, and critical buckling load. The evaluation of the fatigue behaviour (assuming 5.25 × 10⁶ load cycles) applied for each load condition analyzed (levelling from the maximum distance to the minimum, lifting at the maximum distance, lifting at the minimum distance and rotation) shows the magnitude of the safety coefficients both related to the allowable stress and relative to the number of cycles acceptable. The assumption instead of combined cycles (involving one or more load conditions) leads to a significant reduction in the magnitude of the safety coefficients. The implementation of a loading cycle plan resulting from the different load conditions must be reliably assessed to evaluate as accurately as possible the fatigue behavior of the excavator arms made of composite material. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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19 pages, 7560 KiB

Open AccessArticle

Intermediate Crack Debonding of Externally Bonded FRP Reinforcement—Comparison of Methods

by Paweł Tworzewski, Jeffrey K. Alexy and Robert W. Barnes

Materials 2022, 15(20), 7390; https://doi.org/10.3390/ma15207390 - 21 Oct 2022

Cited by 4 | Viewed by 1711

Abstract

Many researchers around the world have made extensive efforts to study the phenomenon of fiber-reinforced polymer (FRP) debonding. Based on these efforts, code provisions and various models have been proposed for predicting intermediate crack (IC) debonding failure. The paper presents a comparison of [...] Read more.

Many researchers around the world have made extensive efforts to study the phenomenon of fiber-reinforced polymer (FRP) debonding. Based on these efforts, code provisions and various models have been proposed for predicting intermediate crack (IC) debonding failure. The paper presents a comparison of seven selected models: fib bulletin 14 approach, Teng et al. model, Lu model, Seracino et al. model, Said and Wu model, Elsanadedy et al. model and ACI 440. The accuracy of each model was evaluated based on the test results of 58 flexural specimens with IC debonding failures of externally bonded (EB), carbon FRP plates or sheets found in the existing literature. The experimental database was prepared to include a wide range of parameters affecting the issue under consideration. A comparison of the measured and predicted load capacity values was made to evaluate the prediction accuracy of the considered models. The analysis included the limitation of the load capacity estimated based on IC debonding models as well as concrete crushing and FRP rupture types of failure. The results indicate that the latest models proposed for direct implementation in design guidelines—the Said and Wu model and the Elsanadedy et al. model—offer the best accuracy in predicting the load capacity. In contrast, the fib bulletin 14 approach shows a wide dispersion of predictions and a large proportion of highly overestimated results. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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17 pages, 3081 KiB

Open AccessArticle

Evaluation of Laminated Composite Beam Theory Accuracy

by Yu-Ting Lyu, Tsung-Pin Hung, Her-Chang Ay, Hsiu-An Tsai and Yih-Cherng Chiang

Materials 2022, 15(19), 6941; https://doi.org/10.3390/ma15196941 - 6 Oct 2022

Cited by 3 | Viewed by 2195

Abstract

Carbon fiber-reinforced polymer (CFRP) has been widely implemented in electric vehicle bodies and aircraft fuselage structures. The purpose of CFRP is to reduce the weight and impart rigidity in the final product. A beam structure is typically used to bear the structural load, [...] Read more.

Carbon fiber-reinforced polymer (CFRP) has been widely implemented in electric vehicle bodies and aircraft fuselage structures. The purpose of CFRP is to reduce the weight and impart rigidity in the final product. A beam structure is typically used to bear the structural load, and the rigidity of the beam can be changed by arranging the laminated fibers at different angles. In this study, a composite I-beam is used as an example in engineering components. Because the theoretical model of the superimposed composite I-beam is established, the theoretical formula is based on the theoretical assumptions of the two-dimensional composite beam, and is combined with the traditional composite plate theory to analyze the maximum bending stress, strain, and deflection. During the theoretical derivation, it is assumed that the flanges of the I-beams are divided into narrow and wide flanges. The beams are considered as structures of beams and flatbeds. When a narrow flange is loaded in the side, the wide flange has no lateral deformation, and the lateral moments are neglected. Therefore, the accuracy of this formula needs to be verified. The purpose of this study is to verify the accuracy of theoretical solutions for the deflection and stress analysis of composite beams. A finite element analysis model is used as the basis for comparing the theoretical solutions. The results indicate that when the aspect ratio of the beam is >15, the theoretical solution will have better accuracy. Without the addition of the material, when 0° ply is placed on the outermost layer of the flange of the nonsymmetric beam, the effective rigidity of the beam is increased by 4–5% compared with the symmetrical beam. The accuracy range of the theoretical solution for the composite beams can be accurately defined based on the results of this study. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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17 pages, 6519 KiB

Open AccessArticle

Assessment of Mechanical Properties for Three-Dimensional Needled Composites: A Geometric Partitioning Strategy Dealing with Mesoscopic Needling Damage

by Rongqiao Wang, Yu Liu, Xi Liu, Dianyin Hu, Jiangbo Han, Penghui Ma and Xiaojun Guo

Materials 2022, 15(16), 5659; https://doi.org/10.3390/ma15165659 - 17 Aug 2022

Cited by 4 | Viewed by 1946

Abstract

A geometric partitioning strategy was proposed to evaluate the mechanical properties of three-dimensional needled composites. The microstructure of the composite was divided to accurately characterize the mesoscopic damage in the needling regions and the macroscopic damage in the un-needling regions, to balance the [...] Read more.

A geometric partitioning strategy was proposed to evaluate the mechanical properties of three-dimensional needled composites. The microstructure of the composite was divided to accurately characterize the mesoscopic damage in the needling regions and the macroscopic damage in the un-needling regions, to balance the computational accuracy and efficiency. The general method of cells (GMC) models along with the damage criteria were established for different material phases in the needling regions, while the continuum damage mechanics (CDM) model was adopted to portray the damage evolution in the un-needling regions. Through conducting the multi-scale simulation, the mechanical properties of the needled composites were predicted, based upon which the effect of repeated needling on the mesoscale damage process was further investigated. Results showed that the predictions are in good agreement with the experiments, with a relative error of 2.6% for strength and 4.4% for failure strain. The proposed approach can provide guidance for the process optimization and design of needled composites. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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13 pages, 4130 KiB

Open AccessArticle

Influence of Hole Localization on Local and Global Dynamic Response of Thin-Walled Laminated Cantilever Beam

by Marcin Bochenski, Jaroslaw Gawryluk and Andrzej Teter

Materials 2021, 14(23), 7409; https://doi.org/10.3390/ma14237409 - 3 Dec 2021

Viewed by 1748

Abstract

In this study, we discuss the effects of the diameter and position of a hole on the dynamic response of a thin-walled cantilever beam made of carbon-epoxy laminate. Eigen-frequencies and corresponding global and local eigen-modes were considered, where deformations of the beam wall [...] Read more.

In this study, we discuss the effects of the diameter and position of a hole on the dynamic response of a thin-walled cantilever beam made of carbon-epoxy laminate. Eigen-frequencies and corresponding global and local eigen-modes were considered, where deformations of the beam wall were dominant, without significant deformation of the beam axis. The study was focused on the circumferentially uniform stiffness (CUS) beam configuration. The laminate layers were arranged as [90/15(3)/90/15(3)/90]_T. The finite element method was employed for numerical tests, using the Abaqus software package. Moreover, a few numerical results of the structure’s behaviour, with and without a hole, were verified experimentally. The experimental eigen-frequencies and the corresponding modes were obtained using an experimental modal analysis, comprising the LMS system with modal hammer. We found that the size and location of the hole affected the eigen-frequencies and corresponding modes. Furthermore, even a small hole in a beam could significantly change the shape of its local modes. The numerical and experimental results were observed to have high qualitative compliance. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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7 pages, 5500 KiB

Open AccessArticle

Interpretation of Specific Strength-Over-Resistivity Ratio in Cu Alloys

by Hongming Li, Shuang Zhang, Yajun Zhao, Xiaona Li, Fushi Jiang and Chuang Dong

Materials 2021, 14(23), 7150; https://doi.org/10.3390/ma14237150 - 24 Nov 2021

Cited by 2 | Viewed by 1615

Abstract

Reaching simultaneously high mechanical strength and low electrical resistivity is difficult as both properties are based on similar microstructural mechanisms. In our previous work, a new parameter, the tensile strength-over-electrical resistivity ratio, is proposed to evaluate the matching of the two properties in [...] Read more.

Reaching simultaneously high mechanical strength and low electrical resistivity is difficult as both properties are based on similar microstructural mechanisms. In our previous work, a new parameter, the tensile strength-over-electrical resistivity ratio, is proposed to evaluate the matching of the two properties in Cu alloys. A specific ratio of 310 × 10⁸ MPa·Ω⁻¹·m⁻¹, independent of the alloy system and thermal history, is obtained from Cu-Ni-Mo alloys, which actually points to the lower limit of prevailing Cu alloys possessing high strength and low resistivity. The present paper explores the origin of this specific ratio by introducing the dual-phase mechanical model of composite materials, assuming that the precipitate particles are mechanically mixed in the Cu solid solution matrix. The strength and resistivity of an alloy are respectively in series and parallel connections to those of the matrix and the precipitate. After ideally matching the contributions from the matrix and the precipitate, the alloy should at least reach half of the resistivity of pure Cu, i.e., 50%IACS, which is the lower limit for industrially accepted highly conductive Cu alloys. Under this condition, the specific 310 ratio is related to the precipitate-over-matrix ratios for strength and resistivity, which are both two times those of pure Cu. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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10 pages, 323 KiB

Open AccessArticle

Multi-Criterial Analysis Tool to Design a Hybrid Ballistic Plate

by Marcin H. Struszczyk, Paulina Dmowska-Jasek, Paweł Kubiak, Marcin Łandwijt and Marzena Fejdyś

Materials 2021, 14(14), 4058; https://doi.org/10.3390/ma14144058 - 20 Jul 2021

Cited by 2 | Viewed by 2254

Abstract

The presented research focuses on the concept of an advanced ballistic personal protection design, taking into account safety as well as performance requirements. The application of the multi-criterial analysis (MCA) allows for a comprehensive comparison of all the properties of materials and to [...] Read more.

The presented research focuses on the concept of an advanced ballistic personal protection design, taking into account safety as well as performance requirements. The application of the multi-criterial analysis (MCA) allows for a comprehensive comparison of all the properties of materials and to select the optimal personal ballistic protection system, considering their mechanical and ballistic properties. The newly developed hybrid ballistic composites, consisting of two or three various components (variations of ballistic and/or non-ballistic textiles; hybrid ballistic plates—HBP), were evaluated via a multi-criterial analysis that considered a wide range of properties, describing behavior and safety usage, as well as the economical aspect of their fabrication. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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14 pages, 4435 KiB

Open AccessArticle

Local Resonant Attenuation of Stress Waves in Particulate Composites

by Dandan Xu and Yu Guo

Materials 2021, 14(11), 2991; https://doi.org/10.3390/ma14112991 - 1 Jun 2021

Cited by 4 | Viewed by 2235

Abstract

The attenuation of stress waves due to the local resonance is numerically studied using the finite element method (FEM) in this work. The natural frequency of a representative composite unit embedded with coated particles is analyzed and the major factors that influence the [...] Read more.

The attenuation of stress waves due to the local resonance is numerically studied using the finite element method (FEM) in this work. The natural frequency of a representative composite unit embedded with coated particles is analyzed and the major factors that influence the natural frequency are examined. Local resonance is inspired when the frequency of the incident stress wave is close to the natural frequency of the particles in the composite. Significant reduction in the amplitude of the stress is obtained when the local resonance occurs, because a large amount of the incident energy is converted to the kinetic energy of the particles, which is rapidly dissipated through the strong oscillations of those particles. It is also observed that the attenuation for the incident stress waves with a range of frequencies can be achieved by using the particles with various local natural frequencies in a composite. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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14 pages, 4424 KiB

Open AccessArticle

Statistical and Microstructural Analyses of Al–C–Cu Composites Synthesized Using the State Solid Route

by Audel Santos Beltrán, Verónica Gallegos Orozco, Miriam Santos Beltrán, Cynthia Gómez Esparza, Iza Ronquillo Ornelas, Carmen Gallegos Orozco, Luz. E. Ledezma Beng and Roberto Martínez Sánchez

Materials 2021, 14(8), 1969; https://doi.org/10.3390/ma14081969 - 14 Apr 2021

Cited by 4 | Viewed by 1860

Abstract

Aluminum powder with different C and C–Cu mixtures powders were fabricated by powder metallurgy, using high-energy mechanical milling as a pre-treatment of powders. To evaluate the combined effect of the C–Cu mixture and the process conditions, such as sintering temperature/time and milling time, [...] Read more.

Aluminum powder with different C and C–Cu mixtures powders were fabricated by powder metallurgy, using high-energy mechanical milling as a pre-treatment of powders. To evaluate the combined effect of the C–Cu mixture and the process conditions, such as sintering temperature/time and milling time, on the yield stress and hardness, two experimental designs were carried out. The results were analyzed with Minitab Statistical Software using contour plots. From the results, better mechanical properties were found at a Cu/C ratio of 0.33 and samples with high C content (3 wt. %). In samples subject to long sintering time (3 h), the mechanism of precipitation of the second phase was mainly present, resulting in an improvement in mechanical properties. From the difference found between the elastic limit and the microhardness tests, it was found that there was an inefficient sintering process affecting the elastic limit test results. Additionally, X-ray analyses using the Rietveld program, were used for microstructural characterization and mechanical parameters of yield strength and ultimate tensile strength. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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11 pages, 3935 KiB

Open AccessArticle

Strengthening and Weakening Effects of Particles on Strength and Ductility of SiC Particle Reinforced Al-Cu-Mg Alloys Matrix Composites

by Zhiyu Yang, Jianzhong Fan, Yanqiang Liu, Junhui Nie, Ziyue Yang and Yonglin Kang

Materials 2021, 14(5), 1219; https://doi.org/10.3390/ma14051219 - 5 Mar 2021

Cited by 18 | Viewed by 2373

Abstract

The strengthening and weakening effects of SiC particles on composite strength and ductility were studied. Al-Cu-Mg alloys matrices with three different mechanical properties were used. Their yield strength, ultimate strength, and elongation range from 90 to 379 MPa, 131 to 561 MPa, and [...] Read more.

The strengthening and weakening effects of SiC particles on composite strength and ductility were studied. Al-Cu-Mg alloys matrices with three different mechanical properties were used. Their yield strength, ultimate strength, and elongation range from 90 to 379 MPa, 131 to 561 MPa, and 18% to 31%, respectively. SiC particles with sizes of 4, 8, 12, 15, 20, and 30 μm were used to reinforce these three matrices, separately, and the composites of eighteen combinations of the particle sizes and matrix strengths were manufactured. Yield strength, ultimate strength, elongation, and fracture morphology of these composites were characterized. Based on the analysis, the strengthening to weakening behavior on strength and ductility were comprehensively discussed. The critical particle size having the best ductility was obtained. The strengthening limit and match range of the particle and the matrix to achieve effective strengthening were defined as a function of the particle size and matrix strength. This work offers an important reference for optimization of mechanical properties of the particle-reinforced metal matrix composites. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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17 pages, 8922 KiB

Open AccessArticle

Effect of Different Coupling Agents on Interfacial Properties of Fibre-Reinforced Aluminum Laminates

by Wei Zhu, Hong Xiao, Jian Wang and Xiudong Li

Materials 2021, 14(4), 1019; https://doi.org/10.3390/ma14041019 - 21 Feb 2021

Cited by 18 | Viewed by 2696

Abstract

Metal composite interface properties significantly affect the integrity, bonding properties, and interface structure of Fibre Metal Laminates (FMLs). Interfacial bonding strength’s effect on Carbon Fibre-Reinforced Aluminium Laminate (CARALL) mechanical behaviours was investigated via three-point bending and low-velocity impact tests. AA6061 sheets were subjected [...] Read more.

Metal composite interface properties significantly affect the integrity, bonding properties, and interface structure of Fibre Metal Laminates (FMLs). Interfacial bonding strength’s effect on Carbon Fibre-Reinforced Aluminium Laminate (CARALL) mechanical behaviours was investigated via three-point bending and low-velocity impact tests. AA6061 sheets were subjected to surface pretreatments under three conditions (anodizing and A-187 and A-1387 surface modifications) to obtain different interfacial bonding strengths. The bonding interfaces of CARALL were analysed using scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Interfacial bonding strength between aluminium alloy and epoxy resin was determined by the tension-shear test. CARALL’s energy absorption capacity and failure mode were analysed after low-velocity impact and three-point bending under different aluminium alloy volume contents and surface pretreatments. Upon modification of metal surfaces, the interfacial bonding strength increased, and the highest was obtained by silane coupling agent A-1387. Improved strength maintained FML’s integrity under quasi-static and dynamic loadings. A-1387 improved the bonding ability of aluminium alloy and Carbon Fibre-Reinforced Plastics (CFRP). The composite interface strongly resisted crack propagation because of its functional group characteristics. When the volume content of aluminium alloy was less and greater than that of CFRP, the energy absorption capacity of CARALL weakened and strengthened, respectively, with increasing interfacial bonding strength. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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11 pages, 8525 KiB

Open AccessEditor’s ChoiceArticle

Effect of the Particle Size and Matrix Strength on Strengthening and Damage Process of the Particle Reinforced Metal Matrix Composites

by Zhiyu Yang, Jianzhong Fan, Yanqiang Liu, Junhui Nie, Ziyue Yang and Yonglin Kang

Materials 2021, 14(3), 675; https://doi.org/10.3390/ma14030675 - 1 Feb 2021

Cited by 28 | Viewed by 3436

Abstract

Roles of the particle, strengthening, and weakening during deformation of the particle reinforced metal matrix composite, were studied using in situ technique. Composites with three different strengths Al-Cu-Mg alloy matrices reinforced by three sizes SiC particles were manufactured and subjected to in situ [...] Read more.

Roles of the particle, strengthening, and weakening during deformation of the particle reinforced metal matrix composite, were studied using in situ technique. Composites with three different strengths Al-Cu-Mg alloy matrices reinforced by three sizes SiC particles were manufactured and subjected to in situ tensile testing. Based on in situ observation, damage process, fraction and size distribution of the cracked particles were collected to investigate the behavior of the particle during composite deformation. The presence of the particle strengthens the composite, while the particle cracking under high load weakens the composite. This strengthening to weakening transformation is controlled by the damage process of the particle and decided by the particle strength, size distribution, and the matrix flow behavior together. With a proper match of the particle and matrix, an effective strengthening can be obtained. Finally, the effective match range of the particle and the matrix was defined as a function of the particle size and the matrix strength. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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12 pages, 1463 KiB

Open AccessEditor’s ChoiceArticle

A New Viscoelasticity Dynamic Fitting Method Applied for Polymeric and Polymer-Based Composite Materials

by Vitor Dacol, Elsa Caetano and João R. Correia

Materials 2020, 13(22), 5213; https://doi.org/10.3390/ma13225213 - 18 Nov 2020

Cited by 10 | Viewed by 2468

Abstract

The accurate analysis of the behaviour of a polymeric composite structure, including the determination of its deformation over time and also the evaluation of its dynamic behaviour under service conditions, demands the characterisation of the viscoelastic properties of the constituent materials. Linear viscoelastic [...] Read more.

The accurate analysis of the behaviour of a polymeric composite structure, including the determination of its deformation over time and also the evaluation of its dynamic behaviour under service conditions, demands the characterisation of the viscoelastic properties of the constituent materials. Linear viscoelastic materials should be experimentally characterised under (i) constant static load and/or (ii) harmonic load. In the first load case, the viscoelastic behaviour is characterised through the creep compliance or the relaxation modulus. In the second load case, the viscoelastic behaviour is characterised by the complex modulus,

E^{*}

, and the loss factor,

η

. In the present paper, a powerful and simple implementing technique is proposed for the processing and analysis of dynamic mechanical data. The idea is to obtain the dynamic moduli expressions from the Exponential-Power Law Method (EPL) of the creep compliance and the relaxation modulus functions, by applying the Carson and Laplace transform functions and their relationship to the Fourier transform, and the Theorem of Moivre. Reciprocally, once the complex moduli have been obtained from a dynamic test, it becomes advantageous to use mathematical interconversion techniques to obtain the time-domain function of the relaxation modulus,

E (t)

, and the creep compliance,

D (t)

. This paper demonstrates the advantages of the EPL method, namely its simplicity and straightforwardness in performing the desirable interconversion between quasi-static and dynamic behaviour of polymeric and polymer-composite materials. The EPL approximate interconversion scheme to convert the measured creep compliance to relaxation modulus is derived to obtain the complex moduli. Finally, the EPL Method is successfully assessed using experimental data from the literature. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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17 pages, 4558 KiB

Open AccessArticle

Collation Efficiency of Poly(Vinyl Alcohol) and Alginate Membranes with Iron-Based Magnetic Organic/Inorganic Fillers in Pervaporative Dehydration of Ethanol

by Gabriela Dudek, Roman Turczyn and David Djurado

Materials 2020, 13(18), 4152; https://doi.org/10.3390/ma13184152 - 18 Sep 2020

Cited by 13 | Viewed by 2362

Abstract

Hybrid poly(vinyl alcohol) and alginate membranes were investigated in the process of ethanol dehydration by pervaporation. As a filler, three types of particles containing iron element, i.e., hematite, magnetite, and iron(III) acetyloacetonate were used. The parameters describing transport properties and effectiveness of investigated [...] Read more.

Hybrid poly(vinyl alcohol) and alginate membranes were investigated in the process of ethanol dehydration by pervaporation. As a filler, three types of particles containing iron element, i.e., hematite, magnetite, and iron(III) acetyloacetonate were used. The parameters describing transport properties and effectiveness of investigated membranes were evaluated. Additionally, the physico-chemical properties of the resulting membranes were studied. The influence of polymer matrix, choice of iron particles and their content in terms of effectiveness of membranes in the process of ethanol dehydration were considered. The results showed that hybrid alginate membranes were characterized by a better separation factor, while poly(vinyl alcohol) membranes by a better flux. The best parameters were obtained for membranes filled with 7 wt% of iron(III) acetyloacetonate. The separation factor and pervaporative separation index were equal to 19.69 and 15,998 g⋅m⁻²⋅h⁻¹ for alginate membrane and 11.75 and 14,878 g⋅m⁻²⋅h⁻¹ for poly(vinyl alcohol) membrane, respectively. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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12 pages, 4269 KiB

Open AccessArticle

Ceramization Mechanism of Ceramizable Silicone Rubber Composites with Nano Silica at Low Temperature

by Penghu Li, Haiyun Jin, Shichao Wei, Huaidong Liu, Naikui Gao and Zhongqi Shi

Materials 2020, 13(17), 3708; https://doi.org/10.3390/ma13173708 - 21 Aug 2020

Cited by 12 | Viewed by 4085

Abstract

Ceramizable composite is a kind of polymer matrix composite that can turn into ceramic material at a high temperature. It can be used for the ceramic insulation of a metal conductor because of its processability. However, poor low-temperature ceramization performance is a problem [...] Read more.

Ceramizable composite is a kind of polymer matrix composite that can turn into ceramic material at a high temperature. It can be used for the ceramic insulation of a metal conductor because of its processability. However, poor low-temperature ceramization performance is a problem of ceramizable composites. In this paper, ceramizable composites were prepared by using silicone rubber as a matrix. Ceramic samples were sintered at different temperatures no more than 1000 °C, according to thermogravimetric analysis results of the composites. The linear contraction and flexural strength of the ceramics were measured. The microstructure and crystalline phase of ceramics were analyzed using scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the composites turned into ceramics at 800 °C, and a new crystal and continuous microstructure formed in the samples. The flexural strength of ceramics was 46.76 MPa, which was more than twice that of similar materials reported in other research sintered at 1000 °C. The maximum flexural strength was 54.56 MPa, when the sintering temperature was no more than 1000 °C. Moreover, glass frit and nano silica played important roles in the formation of the ceramic phase in this research. A proper content of nano silica could increase the strength of the ceramic samples. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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16 pages, 4107 KiB

Open AccessArticle

Study on the Interface Constitutive Relation between Carbon Fiber Fabric and Steel

by Jianjun Shi, Bin Jia, Yinyin Ren, Xiaomei Zhang and Jian Luo

Materials 2020, 13(15), 3263; https://doi.org/10.3390/ma13153263 - 23 Jul 2020

Cited by 4 | Viewed by 2272

Abstract

Peeling failure at the interface is one of the main failure modes for CFRP (Carbon Fiber-Reinforced Polymer)-reinforced steel structures. However, there are very few reported studies on the bond-slip relationship at the CFRP-steel interface. A series of simple shear tests were carried out [...] Read more.

Peeling failure at the interface is one of the main failure modes for CFRP (Carbon Fiber-Reinforced Polymer)-reinforced steel structures. However, there are very few reported studies on the bond-slip relationship at the CFRP-steel interface. A series of simple shear tests were carried out in the present paper. The influence of the fiber fabric’s width and thickness, the surface roughness of the steel sheet, and the thickness of the adhesive layer on the bonding performance of the CFRP fabric to steel interface was considered. The interface constitutive model and bonding strength model were further established under multiple factors. The results show that with the decrease of the surface roughness, the interface’ ultimate peeling load increases gradually, and the failure has a tendency to develop from a glue-steel interface to a glue-CFRP interface. The test pieces that were subjected to sand blasting obtained the peak value of the ultimate peeling load. This indicates that sand blasting can effectively enhance the interface bonding strength. The theoretical values obtained via the interface prediction model are consistent with the experimental values. This proves that the newly developed interface prediction model can effectively predict the local bonding slip and bonding strength of the interface. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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13 pages, 5040 KiB

Open AccessArticle

A Comprehensive Study on the Mechanical Properties of Different 3D Woven Carbon Fiber-Epoxy Composites

by Qiaole Hu, Hafeezullah Memon, Yiping Qiu, Wanshuang Liu and Yi Wei

Materials 2020, 13(12), 2765; https://doi.org/10.3390/ma13122765 - 18 Jun 2020

Cited by 32 | Viewed by 3799

Abstract

In this work, the tensile, compressive, and flexural properties of three types of 3D woven composites were studied in three directions. To make an accurate comparison, three 3D woven composites are made to have the same fiber volume content by controlling the weaving [...] Read more.

In this work, the tensile, compressive, and flexural properties of three types of 3D woven composites were studied in three directions. To make an accurate comparison, three 3D woven composites are made to have the same fiber volume content by controlling the weaving parameters of 3D fabric. The results show that the 3D orthogonal woven composite (3DOWC) has better overall mechanical properties than those of the 3D shallow straight-joint woven composite (3DSSWC) and 3D shallow bend-joint woven composite (3DSBWC) in the warp direction, including tension, compression, and flexural strength. Interestingly their mechanical properties in the weft direction are about the same. In the through-thickness direction, however, the tensile and flexural strength of 3DOWC is about the same as 3DSBW, both higher than that of 3DSSWC. The compressive strength, on the other hand, is mainly dependent on the number of weft yarns in the through-thickness direction. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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16 pages, 5689 KiB

Open AccessArticle

Rivet-Inspired Modification of Aramid Fiber by Decorating with Silica Particles to Enhance the Interfacial Interaction and Mechanical Properties of Rubber Composites

by Yihang Li, Yuzhu Xiong and Qingpo Zhang

Materials 2020, 13(11), 2665; https://doi.org/10.3390/ma13112665 - 11 Jun 2020

Cited by 6 | Viewed by 3312

Abstract

A rivet–inspired method of decorating aramid fiber (AF) with silica particles (SiO₂) is proposed to produce SiO₂@AF hybrid materials that have largely enhanced interfacial interaction with the rubber matrix. AF was firstly surface-modified with polyacrylic acid (PAA) to obtain [...] Read more.

A rivet–inspired method of decorating aramid fiber (AF) with silica particles (SiO₂) is proposed to produce SiO₂@AF hybrid materials that have largely enhanced interfacial interaction with the rubber matrix. AF was firstly surface-modified with polyacrylic acid (PAA) to obtain PAA–AF, and SiO₂ was silanized with 3-aminopropyltriethoxysilane to obtain APES–SiO₂. Then, SiO₂@AF was prepared by chemically bonding APES–SiO₂ onto the surface of PAA–AF in the presence of dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP). With the incorporation of SiO₂@AF into the rubber matrix, SiO₂@AF hybrid materials with high surface roughness can play a role as ‘rivets’ to immobilize large numbers of rubber chains on the surface. The tear strength and tensile strength of rubber composite that filling 4 phr SiO₂@AF are dramatically increased by 97.8% and 89.3% compared to pure rubber, respectively. Furthermore, SiO₂@AF has superiority in enhancing the cutting resistance of rubber composites, in contrast with unmodified AF and SiO₂. SiO₂@AF is suitable to be applied as a novel reinforcing filler in rubber composites for high performance. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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32 pages, 15538 KiB

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Transparent Wood-Based Materials: Current State-of-the-Art and Future Perspectives

by Alberto Mariani and Giulio Malucelli

Materials 2022, 15(24), 9069; https://doi.org/10.3390/ma15249069 - 19 Dec 2022

Cited by 8 | Viewed by 5281

Abstract

Human history is largely characterized by the massive use of wood, the most well-known natural composite material, possessing unique thermal, mechanical, and environmental features that make it suitable for several applications, ranging from civil engineering, art, and household uses, to business uses (including [...] Read more.

Human history is largely characterized by the massive use of wood, the most well-known natural composite material, possessing unique thermal, mechanical, and environmental features that make it suitable for several applications, ranging from civil engineering, art, and household uses, to business uses (including furniture, stationery, shipbuilding, and fuel). Further, as a renewable and recyclable biomass, wood perfectly matches the current circular economy concept. However, because of its structure and composition, wood is not transparent: therefore, the possibility of removing the embedded lignin, hence limiting the light-scattering phenomena, has been investigated over the last ten to fifteen years, hence obtaining the so-called “transparent wood (TW)”. This latter represents an up-to-date key material, as it can be utilized as obtained or further functionalized, combining the transparency with other features (such as flame retardance, energy storage ability, and environmental protection, among others), which widen the potential (and practical) applications of wood. The present manuscript aims at summarizing first the current methods employed for obtaining transparent wood, and then the latest achievements concerning the properties of transparent wood, providing the reader with some perspectives about its novel functionalizations and applications. Full article

(This article belongs to the Special Issue Advanced Composite Materials: Theory, Design and Applications)

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