Effect of Silane Coupling Agent Concentration on Interfacial Properties of Basalt Fiber Reinforced Composites

The purpose of this study is to investigate the effect of the concentration of silane coupling solution on the tensile strength of basalt fiber and the interfacial properties of basalt fiber reinforced polymer composites.The surface treatment of basalt fibers was carried out using an aqueous alcohol solution method.Basalt fibers were subjected to surface treatment with 3-Methacryloxypropyl trimethoxy silane at 0.5 wt.%,1 wt.%,2 wt.%,4 wt.%and 10 wt.%.The basalt monofilament tensile tests were carried out to investigate the variation in strength with the concentration of the silane coupling agent.The microdroplet test was performed to examine the effect of the concentration of the silane coupling agent on interfacial strength of basalt reinforced polymer composites.The film was formed on the surface of the basalt fiber treated silane coupling agent solution.The tensile strength of basalt fiber increased because the damaged fiber surface was repaired by the firm of silane coupling agent.The firm was effective in not only the surface protection of basalt fiber but also the improvement on the interfacial strength of fiber-matrix interface.However,the surface treatment using the high concentration silane coupling agent solution has an adverse effect on the mechanical properties of the composite materials,because of causing the degradation of the interfacial strength of the composite materials.

Mechanical Properties of Mo Fiber-reinforced Resin Mineral Composites with Different Mass Ratio of Resin and Hardener

Mo fibers were added to RMC with different mass ratios of resin and hardener to improve its mechanical properties. The influences of fiber surface state and hardener content on interface bonding strength and mechanical properties of RMC were studied, respectively. Furthermore, strain values of typical measuring points on samples of Mo fiber reinforced RMC(MFRRMC) under different loads were obtained by experiments and finite element analysis. The experimental results prove that scrap Mo fibers can improve interface bonding strength and mechanical properties of RMC better than new smooth Mo fibers because of the discharge pits randomly distributed on the surface of scrap fibers. With the decrease of hardener content, not only interface bonding strength between fiber and matrix, but also compression and flexural strength of MFRRMC increase firstly and then decrease. The properties are best while the mass ratio of resin and hardener reaches 4:1. It is indicated that finite element calculation data basically agree with experimental data by comparison of strain values on typical measuring points, which can provide an important intuitive reference for successive study on other mechanical properties of MFRRMC, validating the correctness of simulation method as well.

Determination of Water Diffusion Coefficients and Dynamics in Adhesive/Carbon Fiber Reinforced Epoxy Resin Composite Joints

To determinate the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis（EDX） is used to establish the content change of oxy- gen in the adhesive in adhesive/carbon fther reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carben fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analy-sis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of beth energy dispersive X-ray spectroscopy and elemental analysis. The de- termined results with EDX analysis are almost the same as those determined with elemental analysis and the results al- so show that the durability of the adhesive/carbon fther reinforced epoxy resin composite joints subjected to silane cou- pling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treat- ment.

Effect of Natural Fiber Reinforced Polypropylene Composite Using Resin Impregnation

In this paper, we deals with mechanical performance of resin impregnation with natural fiber and fiber reinforced composites. The effect of the addition of a rein impregnation process on static strength of the injection molded composites was investigated by carrying out tensile and banding tests, followed by Scanning electron microscopy (SEM) observation of fiber surface and fracture surface of composites. The tensile strength of natural fiber and natural fiber reinforced composites with resin impregnation method increases with Polyvinyl alcohol (PVA) impregnation. In addition, Phenol resin impregnation recovers fiber tensile strength after alkali treatment. Resin impregnation causes decrease in contact surface area;however, it does not cause decrease in mechanical properties. Our results suggest that the using rein impregnation method has better effect on the mechanical properties of natural fiber reinforced Polypropylene (PP) composites.

An Application of the Modified Shear Lag Model to Study the Influence of Thermal Residual Stresses on the Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites

The modified shear lag model proposed recently was applied to calculate thermal residual stresses and subsequent stress distributions under tensile and compressive loadings. The expressions for the elastic moduli and the yield strengths under tensile and compressive loadings were derived which take account of thermal residual stresses. The asymmetries in the elastic modulus and the yield strength were interpreted using the derived expressions and the obtained results of the stress calculations. The model predictions have exhibited good agreements with the experimental results and also with the other theoretical predictions

A New Modification to Shear Lag Model as Applied to Stiffness and Yield Strength of Short Fiber Reinforced Metal Matrix Composites

A new modification for the shear lag model is given and the expressions for the stiffness and yield Strength of short fiber metal matri×composite are derived. These expressions are then compared with our experimental data in a SiCw/Al-Li T6 composite and the published experimental data on different SiCw/Al T6 composites and also compared with the previous shear lag models and the other theoretical models.

Synergistic regulation of current-carrying wear performance of resin matrix carbon brush composites with tungsten copper composite powder

Resin matrix carbon brush composites(RMCBCs)are critical materials for high-powered electric tools.However,effectively improving their wear resistance and heat dissipation remains a challenge.RMCBCs prepared with flake graphite powders that were evenly loaded with tungsten copper composite powder(RMCBCs-W@Cu)exhibited a low wear rate of 1.63 mm^(3)/h,exhibiting 48.6%reduction in the wear rate relative to RCMBCs without additives(RMCBCs-0).In addition,RMCBCs-W@Cu achieved a low friction coefficient of 0.243 and low electric spark grade.These findings indicate that tungsten copper composite powders provide particle reinforcement and generate a gradation effect for the epoxy resin(i.e.,connecting phase)in RMCBCs,which weakens the wear of RMCBCs caused by fatigue under a cyclic current-carrying wear.

Mechanical properties of short carbon/glass fiber reinforced high mechanical performance epoxy resins

To research the relationship between epoxy and fiber inherent property and mechanical properties of composite,we prepared a series of composites using three kinds of high mechanical performance epoxy resins as matrices and reinforced by the same volume fraction(5%)of short carbon and glass fiber.Their mechanical properties were investigated from the perspective of chemical structure and volume shrinkage ratio of epoxy.We analyzed their tensile strength and modulus based on the mixing rule and Halpin-Tsai eq...

Analytical modeling and vibration analysis of fiber reinforced composite hexagon honeycomb sandwich cylindrical-spherical combined shells

This study analyzes and predicts the vibration characteristics of fiberreinforced composite sandwich(FRCS)cylindrical-spherical(CS)combined shells with hexagon honeycomb core(HHC)for the first time based on an analytical model developed,which makes good use of the advantage of the first-order shear deformation theory(FSDT),the multi-segment decomposition technique,the virtual spring technology,the Jacobi-Ritz approach,and the transfer function method.The equivalent material properties of HHC are firstly determined by the modified Gibson’s formula,and the related energy equations are derived for the HHC-FRCS-CS combined shells,from which the fundamental frequencies,the mode shapes,and the forced vibration responses are solved.The current model is verified through the discussion of convergence and comparative analysis with the associated published literature and finite element(FE)results.The effects of geometric parameters of HHC on the dynamic property of the structure are further investigated with the verified model.It reveals that the vibration suppression capability can be greatly enhanced by reducing the ratio of HHC thickness to total thickness and the ratio of wall thickness of honeycomb cell to overall radius,and by increasing the ratio of length of honeycomb cell to overall radius and honeycomb characteristic angle of HHC.

Mechanical and Microstructural Characteristics of the Fiber-Reinforced Composite Materials

Composite fiber materials are superior materials due to their high strength and light weight. Composites reflect the properties of their constituents, which is proportional to the volume fraction of each phase. There are different fiber reinforcement types and each affects its flexural, tensile and compression strength. When selecting a composite for a specific application, the forces excreted on the composite must be known in order to determine the reinforcement type. Unidirectional fiber reinforcement will allow very strong load resistance but only in one direction where as a random orientated fiber reinforcement can resist less load but can maintain this quota in all directions. These materials are said to be anisotropic. Certain composite fibers, taking into consideration their weights, are physically stronger than conventional metals. In this paper, specific light-weight components with different reinforcement types, volume fraction and phase content were newly composed, tested, characterized and evaluated. By applying a novel method, a model which including the various matrix compositions, reinforcement types of each specific component, and its dual-properties was developed according to the structure characteristics. It was shown that certain reinforced composites such as carbon fiber, tend to be much stronger than metals when taking account its weight ratio. The outcome of this research lays a good foundation for the further carbon fiber-based material design work.

Fabrication and Characterization of Glass Fiber with SiC Reinforced Polymer Composites

Glass Fiber Reinforced Polymeric (GFRP) Composites are most commonly used as bumpers for vehicles, electrical equipment panels, and medical devices enclosures. These materials are also widely used for structural applications in aerospace, automotive, and in providing alternatives to traditional metallic materials. The paper fabricated epoxy and polyester resin composites by using silicon carbide in various proportions along with GFRP. The hand lay-up technique was used to fabricate the laminates. To determine the properties of fabricated composites, the tensile, impact, and flexural tests were conducted. This method of fabrication was very simple and cost-effective. Their mechanical properties like yield strength, yield strain, Young’s modulus, flexural modulus, and impact energy were investigated. The mechanical properties of the GFRP composites were also compared with the fiber volume fraction. The fiber volume fraction plays a major role in the mechanical properties of GFRP composites. Young’s modulus and tensile strength of fabricated composites were modelled and compared with measured values. The results show that composites with epoxy resin demonstrate higher strength and modulus compared to composites with polyester resin.

Material Properties and Mold Folded Core Based on Ultra-violet Cured Resins

Ultra-violet(UV)curing is an efficient method for composite molding.Firstly,thermophysical properties of UV cured glass-fiber reinforced plastics are conducted.Material properties are studied for various kinds of postcuring modes.Then the UV curing method is suggested in manufacturing V-crimp folded core for sandwich panels.Two kinds of processing schemes for V-crimp folded core manufacturing using UV curing are presented.Finally,the effect of post-curing on the mechanical properties of folded core sandwiches is experimentally studied,and optimum modes of post-curing are determined.The experimental results show that the ultimate compressive strength of the folded sandwiches is increased by 60% after post-curing with the optimum post-curing mode.

Experimental Investigation of Natural Fiber Reinforced Polymers

The potential usage of virgin Low density polyethelyne (LDPE) reinforced with different concentrations (2%, 5% and 6% by weight) of treated rice straw with different lengths (2 mm, 4 mm and 6 mm) is investigated to produce high value products that have technical and environmental demand. The two treatment methods used for rice straw are alkali and acidic treatments of rice straw. The removal of impurities and waxy substances from fiber surface avoid creation of rougher topography after treatment and improves the quality of fiber, also content of hemi cellulose and lignin decrease so increase effectiveness of fiber due to dispersing of fiber in matrix. The reinforcing material is embedded in the matrix material to enhance tensile and flexural behaviors of the synthesized composite. The result of investigating these two mechanical properties, using statistical analysis & design of experiments, showed an enhancement in the mechaniccal properties of the virgin polymer composite compared to the virgin polymer. The flexural stress of the composite increased three times the virgin flexural stress, while the tensile stress increased eight times the original tensile stress.

Study of Maleic Anhydride Grafted Polypropylene Effect on Resin Impregnated Bamboo Fiber Polypropylene Composit

Previously, Polyvinyl Alcohol (PVA) and phenolic resin were used for resin impregnated bamboo fiber reinforced PP composites which was manufactures for resin impregnated bamboo fiber with polypropylene (PP). Resin impregnation method can show improvement on tensile strength of fiber. However, to reduce the contact surface area and low inter-facial shear strength (IFSS) between impregnated resin and matrix, using 40% weight fraction of bamboo fiber in PP matrix, PVA impregnated composites with mean flexural and tensile strength 10% higher than untreated composites were produced butphenolic resin impregnated fiber reinforced composition’s mechanical properties were decreased. In this study maleic anhydride grafted polypropylene (MAPP) was used to increase interfacial shear strength between resin impregnated fiber and PP. With 10% MAPP, IFSS between resin impregnated fiber and PP increased more than 100% and reinforced composites. MAPP with untreated, phenolic resin and PVA impregnated cases showed similar mechanical properties. Yet in water absorption test, the PVA treatment with bamboo/PP composites increased water absorption ratio. But with 10% MAPP, matrix PP water absorption ratio decreased like phenolic resin impregnated fiber reinforced composites. 10% MAPP with resin impregnated bamboo fiber reinforced PP composites can improve IFSS, mechanical properties of composite and can decrease water absorption PVA resin impregnated bamboo fiber reinforced composites.

Natural Composite Material from Steelwool or Luffa cylindrica under Natural, Rigid and Flexible Resin

In a changing world with a high interest in new ecomaterials, natural fibers such as the steelwool or Luffa cylindriea appear in new presentations and mixing with other materials to develop better opportunities to replace synthetic fibers. This work presents a research on the use of steelwool fiber for composite materials, on the basis of the physical properties, that generate conditions of mixing with three binders （matrix） natural： the rosin, artificial hard： polyurethane resin and artificial flexible： flexible twin resin （epoxy） and finally a polyester resin to make a comparison with other major resins. A testing of compression and tension is carried out to the materials analyzed, obtaining three types of composite materials by the above mentioned binders and three proposed presentations of fiber （complete, tissue and ground）. The test tube in tension with polyester resin presented a high rigidity and a percentage of deformation of 14%, resulting in less distortion than the woven with resin polyurethane with 12% of deformation. The presentation with resin polyurethane presented greater resistance to compression, because the resin acts as a sponge absorbing the energy of charge and the join of particles is larger than the other presentations generating greater cohesion among them and avoiding its rupture easily for a load of 2,000 kg. The presentation that is least resisted was the woven in two resins in the stage of energy absorption of load where polyurethane is 800 kg and the flexible twin is 850 kg, because the form of woven fiber distribution creates spaces where there are more resin than fiber.

Progress in Recycling of Composites with Polycyanurate Matrix

Thermoset based composites are used increasingly in industry for light weight applications, mainly for aircraft, windmills and for automobiles. Fiber reinforced thermoset polymers show a number of advantages over conventional materials, like metals, especially their better performance regarding their strength-to-weight ratio. However, composite recycling is a big issue, as there are almost no established recycling methods. The authors investigate the recyclability of polycyanurate homo- and copolymers with different recycling agents under different conditions. Also the influence of the recycling process on the most important reinforcement fibers, i.e. carbon-, glass-, aramid-, and natural-fiber is investigated. The authors find that: the recycling speed is not only dependent on the temperature, but also is significantly influenced by the particular recycling agents and the polycyanurate formulation. Hence, the stability against the recycling media can be adjusted over a broad range by adjusting the polymer composition. Furthermore, the authors find that the inorganic reinforcement fibers (carbon and glass) are almost unaffected by neither recycling agent at either temperature. Aramid-fibers degrade, depending on the particular recycling agent, from slightly up to extremely strong. This leaves one with the possibility to find a combination of matrix resin and recycling agent, which does not affect the aramid-fiber significantly. In the case of natural fibers, the dependence on the particular recycling media is very strong: some media do not affect the fiber significantly;others reduce the mechanical properties (tensile strength and elongation at break) significantly, and still others even improve both mechanical properties strongly. From the Recyclate, the authors synthesize and subsequently characterize a number of new polyurethane thermosets (foamed and solid samples) with different contents of recyclate, exhibiting Tg in the range of 60°C to 128°C.

桥梁工程中的纤维增强树脂基复合材料应用进展

为满足恶劣环境条件下现代化桥梁工程高质量建造所需材料的力学性能、耐腐蚀性及耐疲劳性等要求,基于纤维增强树脂基复合材料的优异性能,从公路桥、观赏桥、梁式桥以及超大跨度悬索桥等不同工况要求下的桥梁建设出发,总结了纤维增强树脂基复合材料的发展与应用现状。指出纤维增强树脂基复合材料在桥梁工程应用中仍存在应力损失、受风力影响大及回收处理难等弊端,并提出了主要的解决思路。

麻纤维增强改性环氧树脂复合材料声学性能研究

为验证麻纤维增强改性环氧树脂复合材料的声学性能,探讨植物纤维改性材料制备某类乐器的可行性,以亚麻、黄麻、苎麻等麻纤维材料为例,制备了几种不同麻纤维增强改性环氧树脂材料,以增强改性环氧树脂材料代替木材制作打击乐器,采用自由振动方法对打击乐器的声学性能进行测试。结果表明:黄麻、苎麻增强改性后的环氧树脂基复合材料声学性能各占优势,与一般的枫木相比力学性能更好,但综合声学性能尚无法达到天然枫木的水平。

玻璃纤维增强不饱和聚酯树脂防火隔板湿热老化特性

为了研究玻璃纤维增强不饱和聚酯树脂防火隔板湿热老化特性,结合电缆隧道内实际温湿环境和加速老化模型对防火隔板进行等效湿热老化处理。通过扫描电镜试验、热重试验、氧指数试验以及冲击强度试验检测了试样的微观形貌、热稳定性、燃烧性能和机械性能。结果表明,老化1周期后试样表面析出白色粉状物、老化3周期后断面出现明显裂痕;微观形貌图显示老化2周期后试样中的树脂从玻璃纤维上脱落,老化5周期后大量玻璃纤维裸露在外。试样质量损失率峰值最终升高45%,冲击强度最终下降41.6%,抗弯强度最终降低47.3%,吸水抗弯强度最终下降42.5%,表明湿热老化后试样热稳定性及机械性能出现明显下降。试样氧指数最终提高28.7%;烟密度等级均满足技术规范标准。上述两项检测无法作为判断湿热老化后防火隔板性能劣化的指标。

纤维增强热塑性复合材料与金属连接技术的研究进展

纤维增强热塑性复合材料(FRTP)与金属的连接技术是多材料异质结构的关键制造技术。总结了纤维增强热塑性树脂基复合材料相对于传统金属材料的性能优势,分析了FRTP与金属连接技术的重要性和必要性,系统回顾了胶接、机械连接、混合连接和焊接四大类FRTP/金属连接技术的特点和发展,最后对未来FRTP/金属异质结构连接技术的发展、接头性能的改善提出了展望。