Resin Matrix Composites Research Articles

Multi-scale Synergistic Strengthening and Toughening에 따른 에폭시 수지 매트릭스 복합체의 기계적 특성 분석

A multi-scale synergistic modification technology is proposed to strengthen and toughen epoxy resin matrix composites, which can be used in the direct extrusion fabrication process. The toughness performance of epoxy resin matrix composites can be improved without compromising other advantages by adding micrometer- and nanometer-scale fillers to the matrix and optimizing the content of fillers, surface treatment process, dispersion method, and other parameters. We analyzed and discussed the mechanical properties of epoxy-based composites with micrometer-scale fillers, nanometer-scale fillers, and mixed multi-scale fillers. When 15 phr carbon fibers (15CFs), 6 phr rubber nanoparticles (6RNPs), and 1 phr carbon nanotubes (1CNTs) are added to epoxy resins (EPs), the tensile strength reached 91.6 MPa, 28.8% higher than that of the pure EPs; the achieved elastic modulus 4.72 GPa, 77.4% higher than the pure EPs; the fracture toughness was 2.97 MPa mSUP1/2/SUP, 241.4% of the pure EPs, while the impact strength reached 63.4 kJ/mSUP2/SUP, 369.6% higher than the pure EPs. The results show that the multi-scale reinforcements exhibit a synergistic effect on the strength and toughness of the composites.

Shielding performances of short carbon fibers and tungsten particles reinforced benzoxazine resin matrix composites

This present investigation reports, for the first time, the properties of the polybenzoxazine bio-based furfurylamine reinforced using the hybrid short carbon fibers and tungsten particles. The results revealed good compatibility between the matrix and the filers using scanning electron microscopy, due to the use of the silane treatment that led to enhanced interfacial bonding. In addition, the mechanical data disclosed that the bending and impact values were respectively increased to 210 MPa and 9 KJ/m2 for the composites containing 20%wt of the short carbon fibers and 20%wt tungsten particles. The hybrid composite shielding properties were evaluated using the cobalt-60 as an irradiation source, and the nuclear results depicted that the half-value length and the tenth-value length were increased as compared to those of the pure polymers. Based on the thermal stability studies, the reinforced hybrid composites also showed excellent thermal resistance.

Effect of sizing agent on properties of basalt fiber/blended resin matrix composites

Effect of sizing agent on properties of basalt fiber/blended resin matrix composites

Mechanical properties and wear resistance of Cf / epoxy resin composites with in-situ grown SiC nanowires on carbon fibers

ABSTRACT Carbon fiber-reinforced resin matrix composites have been utilized as structural and bearing parts in aerospace because of their high specific strength and modulus. To improve the mechanical properties and wear resistance of carbon fiber-reinforced epoxy resin composites, we propose the in-situ growth of SiC nanowires on the surface of carbon fiber by a Chemical Vapor Deposition method. The effect of the addition of nanowires on the mechanical strength and wear resistance of carbon fiber-reinforced epoxy resin composites was investigated. The results indicated that the tensile strength and bending strength of SiCnws / C f / epoxy resin composites increased by 13.8% and 16.2% on the condition that the concentration of Ni(NO3)2 catalyst was 0.1 mol/L, respectively. The improvement of the mechanical properties could be attributed to the mechanical interlocking affection between carbon fiber and SiC nanowires. In addition, due to SiC nanowires with a three-dimensional network structure on the surface of carbon fiber, the stronger adhesive force between epoxy matrix SiC nanowires protected the resin matrix and carbon fiber from abrasion. The wear rate of SiCnws / C f / epoxy composites was reduced by 98.1%.

Microscopic Inspection of the Adhesive Interface of Composite Onlays after Cementation on Low Loading: An In Vitro Study.

This study aimed to assess the layer thickness and microstructure of traditional resin-matrix cements and flowable resin-matrix composites at dentin and enamel to composite onlay interfaces after cementation on low loading magnitude. Twenty teeth were prepared and conditioned with an adhesive system for restoration with resin-matrix composite onlays manufactured by CAD-CAM. On cementation, tooth-to-onlay assemblies were distributed into four groups, including two traditional resin-matrix cements (groups M and B), one flowable resin-matrix composite (group G), and one thermally induced flowable composite (group V). After the cementation procedure, assemblies were cross-sectioned for inspection by optical microscopy at different magnification up to ×1000. The layer thickness of resin-matrix cementation showed the highest mean values at around 405 µm for a traditional resin-matrix cement (group B). The thermally induced flowable resin-matrix composites showed the lowest layer thickness values. The resin-matrix layer thickness revealed statistical differences between traditional resin cement (groups M and B) and flowable resin-matrix composites (groups V and G) (p < 0.05). However, the groups of flowable resin-matrix composites did not reveal statistical differences (p < 0.05). The thickness of the adhesive system layer at around 7 µm and 12 µm was lower at the interfaces with flowable resin-matrix composites when compared to the adhesive layer at resin-matrix cements, which ranged from 12 µm up to 40 µm. The flowable resin-matrix composites showed adequate flowing even though the loading on cementation was performed at low magnitude. Nevertheless, significant variation in thickness of the cementation layer was noticed for flowable resin-matrix composites and traditional resin-matrix cements that can occur in chair-side procedures due to the clinical sensitivity and differences in rheological properties of the materials.

Study on wear resistance of local aluminum alloy reinforced by carbon fiber transfer membrane region

In order to study the effect of fiber reinforced resin matrix composites on the friction properties of aluminum alloy, 7075 aluminum alloy, Carbon fiber reinforced plastic (CFRP) and 7075-Al/CFRP hybrid samples were selected for pin-disk friction test. White light interference and scanning electron microscopy were used to analyze the surface morphology of the friction samples. Secondly, the formation process of the transfer membrane was analyzed by Raman test and energy spectrum. Finally, the strength of the transfer film was verified by scratch test. The results showed that the friction coefficients of 7075-W and 7075-T6 aluminum alloy are 0.419 and 0.398, and the wear rates are 0.288% and 0.273%, respectively. For CFRP and 7075-Al/CFRP hybrid samples, the microscopic study of friction interface showed that CFRP and aluminum alloy abrasive particles exchanged elements under the dual action of pressure and shear force, thus forming Transfer Membrane Region (TMR). TMR with strong self-lubrication preferentially supported the friction load during the friction process, thus reducing the friction and wear of aluminum alloy. The friction coefficient and the wear rate of the 7075-Al/CFRP hybrid sample were reduced by 62.5% and 78.2%, respectively in comparison to pure 7075 aluminum alloy sample.

Design and spraying-preparation of the gradient coatings with various diameters and contents of SiO2 nano-particles for the enhanced anti-impact and thermal insulation performance

Composites used in aircraft are vulnerable to mechanical and thermal damage during particle impact at high speeds. In this paper, a series of gradient polyurethane silica coatings with different silica particle sizes and concentration gradients were prepared on epoxy resin matrix composites by pneumatic spraying process. The results of corundum impact and thermal insulation performance experiments indicated that multi-layer gradient coatings improved the particle impact resistance and thermal insulation. The damage was reduced to <1 % of surface damage area and thickness loss under the protection of enhanced gradient coatings, showing excellent particle impact resistance. Under unidirectional heating conditions, the temperature difference between the heating plate and the sample surface was four times that of the unprotected sample, from 2.2 °C to 9.4 °C, and the total thermal conductivity of the protected sample was reduced by 91.73 %. The coatings remained intact under high-speed particle collision of 300 A plasma flow, which verified the protection performance of the coatings simulating the situation that the coatings were impacted by particles and heated simultaneously. The as-prepared gradient coatings can effectively enhance the anti-impact and thermal insulation performance of composites, exhibiting wide application prospects.

Study on Optimization of Drilling Parameters for Laminated Composite Materials

Fiber-reinforced resin matrix composites have been widely used in aerospace, construction, transportation and other industries due to their excellent mechanical properties and flexible structural design. However, due to the influence of the molding process, the composites are easily delaminated, which greatly reduces the structural stiffness of the components. This is a common problem in the processing of fiber-reinforced composite components. In this paper, through the combination of finite element simulation analysis and experimental research, drilling parameter analysis was carried out for prefabricated laminated composites, and the influence of different processing parameters on the processing axial force was qualitatively compared. The inhibition rule of variable parameter drilling on the damage propagation of initial laminated drilling was explored, which further improves the drilling connection quality of composite panels with laminated materials.

Manufacturing and damping properties of microflake–nanoflake reinforced carbon fiber epoxy resin matrix composites

Due to the high strength, high modulus, lightweight and other characteristics, carbon fiber reinforced polymer (CFRP) is widely used in aerospace, high-speed aircraft, and other fields. In this article, a high-damping CFRP reinforced by flake polyurethane fillers is prepared with good mechanical properties, and the effects of flake polyurethane fillers on the mechanical and damping properties of CFRP are studied. The results show that the mechanical and damping properties of CFRP could be significantly improved by the appropriate content of the flake polyurethane fillers. In addition, the optimal content of the flake polyurethane fillers is 3 wt.%, and the flexural strength, interlaminar shear strength, and damping properties of CFRP are increased by 6.19%, 12.07%, and 9.48%, respectively.

Buckling of helically wound composite cylinders under uniform external pressure

ABSTRACT This study investigated the buckling behaviours of helically wound composite cylinders subjected to uniform external pressure. Three composite cylinders with lengths 180, 280, and 380 mm were manufactured through ±55° winding. Cylinders with a wall thickness of 3.12 mm and inner radius of 103 mm were constructed from carbon fibre reinforced resin matrix composites. Externally hydrostatic tests were conducted to determine the collapse strength and postcollapse modes of the three cylinders. Furthermore, the analytical, linear eigenvalue, and Riks methods were used to study their buckling behaviours. The experimental, analytical, and numerical data agreed well with each other. The Riks method considers Hashin damage initiation and linear damage evolution and can therefore be used to reasonably estimate the postcollapse modes of cylinders.

Ablation and mechanical properties of ZrC-reinforced PBI resin matrix composites

With the rapid development of laser technology, there is an increasing demand for laser protective materials. Thus, the mechanical and ablation properties of composite materials need to be further enhanced. Herein, solution impregnation and hot-press molding were used to develop composites containing various mass ratios of ZrC to polybenzimidazole (PBI) resin (thickness = 3 mm) for laser ablation applications. The results showed that adding short carbon fiber (SCF) to ZrC/PBI composites improves the ablation and mechanical properties. The ZrC/PBI/SCF composites were ablated using a high-energy continuous laser (7 kW cm−2), and the composites did not burn through. The composites did not peel off or split as the ablation process progressed. With the increase in the ZrC content in the composites, dense oxide layers are formed, enhancing the ablation properties of the composites. The ZrC/PBI/SCF composite (the ZrC/PBI mass ratio = 2:1) exhibited the lowest mass loss (2.24%), mass ablation rate (0.119 mg s−1) and linear ablation rate (0.032 mm s−1). This indicates that ZrC/PBI/SCF composites can be used as protective materials in high-energy continuous laser applications.

Strengthening and Toughening Epoxy Composites by Constructing MOF/CF Multi-Scale Reinforcement

The interfacial designing of carbon fiber (CF)/epoxy composites, as a well-accepted method used to obtain high-performance composites, has gained extensive attention. However, an improvement in interfacial adhesion is usually accompanied by a simultaneous decrease in toughness, which has become an obstacle to the performance enhancement of CF/epoxy composites. Herein, nanosized UiO-66-NH2 was proposed to yield on the CF surface through an in situ growth method for preparing high-performance CF/epoxy composites. The induced UiO-66-NH2 could significantly enhance the active groups, surface roughness and wettability on the fiber surface, which can be confirmed by XPS, FTIR, dynamic contact angle (DCA) and SEM. Moreover, the porous structure of UiO-66-NH2 enables the epoxy resin to pass through it, which could toughen the matrix by forming an interpenetrating network structure and reducing the density of resin crosslinking. Meanwhile, the size effect of UiO-66-NH2 could hinder the crack propagation and release the stress concentration. Benefiting from these interfacial strengthening and toughening effects, the interlaminar shear strength and impact strength increased by 44.2% and 27.6%, respectively, in comparison to those of untreated CF. This work proposes a simple and effective strategy for interfacial designing that could offer new ideas for solving the conflict between the strengthening and toughening and provide a practical basis for preparing high-performance resin matrix composites.

Preparation of CaCO3/Al(OH)3 Composites via Heterogeneous Nucleation.

As one of the most widely used inorganic fine powder fillers, calcium carbonate is cheap. However, considering its poor light transmittance, it is not suitable to be added to resin matrix composites that require high light transmittance. Aluminum hydroxide has good light transmission and flame retardancy, but it is more expensive than calcium carbonate. CaCO3/Al(OH)3 composites with a core-shell structure that showed a trend toward the performance of aluminum hydroxide not only improved the surface properties of CaCO3, but also increased the added value of CaCO3. In the present paper, CaCO3/Al(OH)3 composites were successfully prepared in sodium aluminate solution via heterogeneous nucleation. Four types of calcium sources, including calcite-type precipitated calcium carbonate, vaterite-type precipitated calcium carbonate, ground calcium carbonate with two different particle sizes as the precursors and supersaturated sodium aluminate solution as the substrate, have been deeply investigated in terms of their influence on the preparation of CaCO3/Al(OH)3 composites. Results showed that the calcium carbonate precursor greatly affected the formation of CaCO3/Al(OH)3 composites. Both the precipitated calcium carbonate and the small particle ground calcium carbonate are likely to undergo anti-causticization and a complexation reaction with it to generate 3CaO·Al2O3·6H2O and 3CaO·Al2O3·CaCO3·11H2O, which go against the coating of calcium carbonate with aluminum hydroxide. Within the experimental range, the use of ground calcium carbonate with a particle size of 400-500 mesh is more suitable as a precursor for the preparation of core-shell CaCO3/Al(OH)3 composites.

Application of fibre reinforced resin matrix composites in the reinforcement of high voltage transmission towers

Application of fibre reinforced resin matrix composites in the reinforcement of high voltage transmission towers

Application of fibre reinforced resin matrix composites in the reinforcement of high voltage transmission towers

Application of fibre reinforced resin matrix composites in the reinforcement of high voltage transmission towers

Predicting and Improving Interlaminar Bonding Uniformity during the Robotic Fiber Steering Process.

With their high specific stiffness, corrosion resistance and other characteristics, especially their outstanding performance in product weight loss, fiber-reinforced resin matrix composites are widely used in the aviation, shipbuilding and automotive fields. The difficulties in minimizing defects are an important factor in the high cost of composite material component fabrication. Fiber steering is one of the typical means of producing composite parts with increased strength or stiffness. However, fiber waviness is an important defect induced by fiber steering during the fiber placement process. Meanwhile, the laying speeds of the inner and outer tows along the path width direction are different during the fiber steering process, resulting in different interlaminar bond strengths. Therefore, the fiber waviness and uneven interlaminar bonding strength during fiber steering not only affect the dimensions of a composite product, but also influence the mechanical properties of the part. This study aims to reduce fiber waviness and improve interlaminar bonding uniformity along the path width direction using a multi-piece compaction roller. By analyzing the mechanism of the generation of fiber waviness, the interlaminar bonding strength for each tow during fiber steering is investigated. Through analyzing and optimizing the compaction force, laying temperature and laying velocity during fiber steering experiments, the optimization approach is verified.

Study on the aging properties of 3D woven composites under corrosive conditions

Different aging conditions have an important influence on the performance of carbon fiber composites. In this study, the properties of three-dimensional woven carbon fiber reinforced resin matrix composites were investigated and analyzed in three different aging environments (distilled water immersion, 30% H2SO4 solution immersion, and 10% NaOH solution immersion) at 60°C. Mass change, moisture absorption change, Fourier transform infrared spectra (FTIR), surface morphology before and after aging, glass transition temperature (Tg), compression properties, bending properties, and interlayer shear properties were analyzed. The results showed that the immersion in 10% NaOH solution made the specimens destroyed and the aging process was chemically changed. Distilled water immersion and 30% H2SO4 solution immersion moisture absorption rate to meet the FICK law, the aging process only physical changes. The surface of the composite specimens under the three aging conditions produced different degrees of cracks and different degrees of debonding at the interface between the fibers and the resin matrix. The Tg, flexural properties, interlaminar shear properties, and compressive properties of the aged specimens all showed different degrees of degradation.

Oxidation and ablation behavior of a ceramizable resin matrix composite based on carbon fiber/phenolic resin

A ceramizable resin matrix composite with an alternating distribution of modifying fillers, namely borosilicate glass, Si, and ZrSi 2 , was designed based on carbon fiber/phenolic resin composite. Polycarbosilane was introduced as an interface layer. The oxidation and ablation behavior of the ceramizable resin matrix composite were studied. The results show that the strength of the composite after oxidation at 1200–1500 ℃ for 1800 s was around 100 MPa. The ablation resistance and thermal insulation of the composite are improved simultaneously due to the synergistic effect among borosilicate glass, Si, and ZrSi 2 . This result is attributed to the decrease in the discharge rate of pyrolysis gas through a two-step reaction and generation of ceramics with a high temperature and ablation resistance. These results indicate that the proposed composite is a promising low-cost material with a good strength and a good ablation resistance for application in thermal protection systems.

Laminate Design of Carbon-Fiber-Reinforced Resin Matrix Composites for Optimized Mechanical Properties and Electrical Conductivity.

Carbon fiber composites as pantograph slide materials are in the development stage, in which copper is the conductive phase, and the addition form and size need to be designed. Herein, the effects of the copper morphology, the size of the copper mesh on the performance, and the influence of the contact mode between the sliding plate and bracket on the temperature rise were compared and analyzed. The resistivity is 11.2 μΩ·m with the addition of 20 wt% copper mesh, a relative reduction of 91.77%. Importantly, the impact strength is increased by 14.19%, and the wear is reduced by 13.21%; hence, the copper mesh laid in layers is the ideal structure. Further study of the distribution and quality of the copper mesh shows that the resistivity is related only to the quality of the copper mesh; in addition, the number of layers of the copper mesh cannot exceed 16, and it is determined that the best type of copper mesh is 5#. Notably, the performance can be improved by appropriately reducing the thickness of the copper mesh and increasing the aperture while the sliding plate and the bracket are connected by copper mesh with conductive adhesive, which has the slowest heating rate of 2.27 °C/min and the smallest resistance. Therefore, the influence of copper content and distribution on the electrical conductivity are systematically investigated, and the mechanical properties and electrical conductivity are optimized through the design of the laminate structure of the compound material.

Laser Joining of Continuous Carbon Fiber-Reinforced PEEK and Titanium Alloy with High Strength.

The generation of high-performance heterojunctions between high-strength resin matrix composites and metals is of great significance for lightweight applications in fields such as aerospace and automobile engineering. Herein, we explored the feasibility of employing a laser joining process to achieve high-strength heterojunctions between continuous carbon fiber-reinforced PEEK (CCF30/PEEK) composites and titanium alloy (Ti6Al4V). A joint strength of over 50 MPa was achieved through constructing mechanical interlocking structures between CCF30/PEEK and Ti6Al4V. Tensile tests revealed that the fracture of joints was mainly ascribed to the detachment of carbon fibers from the resin matrix and the breakage of carbon fibers. The structures with different orientations and dimensions were confirmed to significantly influence the formation of interlocking structures near the joining interface and the resultant fracture strength of joints. It is believed that the results presented in this study provide a strong foundation for the production of high-performance heterojunctions.