Study On The Structures And Properties Of Carbon Fiber/glass Fiber Hybrid Fabric Vacuum Pouring Composites For Wind Turbine Blades Application

In recent years,with the rapid development of offshore wind power and low-wind wind power,pure glass fiber reinforced composite has become increasingly unable to solve the problem of insufficient stiffness caused by large blade size.Carbon fiber reinforced resin matrix composite material is a kind of high rigidity and light weight material.Its application in wind turbine blade can improve the structural stiffness and strength of the blade,and reduce the weight of the structure.But the high price of carbon fiber has limited its large-scale use in wind turbine blades.The hybrid of carbon fiber and glass fiber can significantly improve the stiffness and modulus of wind turbine blades and effectively reduce the raw material and production cost without changing the traditional composite forming process.Therefore,it is expected to be widely used in the field of wind turbine blades.In this paper,the interlamellar hybrid composites were prepared by vacuum assisted resin perfusion molding(VARI).The structure and properties of interlamellar hybrid composites with different hybrid ratios were systematically studied,especially the structure and properties of the composites after wet and hot aging.At the same time,the hybrid fabric in carbon fiber and glass fiber layer was designed and customized independently,and the structure and properties of the hybrid composite in carbon glass layer were systematically studied,especially the structure and properties after wet and heat aging.The specific contents and conclusions of this study are as follows:(1)Carbon fiber and glass fiber fabrics of different proportions were selected to prepare interlayer hybrid carbon glass composites with different hybrid ratios through VARI process,and the influence of hybrid ratios on the structure and properties of interlayer hybrid carbon glass composites was systematically studied.The results show that the tensile,compression,bending and interlaminar shear properties of carbon glass interlaminar hybrid composites change significantly with the increase of the hybrid ratio of carbon fiber to glass fiber.The tensile strength at 0° increases.The tensile strength of 90° decreases with the effect of binding yarn.0° compression strength and0° compression modulus increase accordingly.The bending strength has an increasing trend,but there is no obvious rule,and the bending modulus increases.The interlaminar shear strength increases accordingly.The glass transition temperature of hybrid composites is generally decreasing.(2)The hygrothermal aging behavior of interlaminar hybrid composites with different hybrid ratios of carbon glass was systematically studied by water bath heating method.It was found that there was no significant relationship between the diffusion coefficient of water and the hybrid ratio of carbon glass in the hybrid composites after 98 days of heating in a water bath at 80?.The retention rate of tensile strength at 0° is above 55%,and that at 90° is above 35%.The retention rate of 0° compression strength and 0° compression modulus are all above 34% and 92%respectively.The retention rate of bending strength and bending modulus are all above 37 % and81% respectively.The retention rate of interlaminar shear strength is above 47 %.The decrease of glass transition temperature is less than 21%.In the humid and hot environment with the increase of time,the mechanical properties of carbon glass interlayer hybrid composites tend to be stable when they decrease to a certain extent.Scanning electron microscopy(SEM)observation of the90° tensile fracture section of the composite shows that the resin content of the hybrid composite between the carbon glass layers decreases obviously after wet and hot aging,and the internal void becomes larger,and the interface between the fiber and the resin is seriously damaged.(3)Carbon fiber and glass fiber were mixed in a certain proportion to prepare fabrics,and hybrid composites with different hybrid ratios were prepared by VARI process.The influence of hybrid ratio on the structure and properties of hybrid composites in carbon glass layer was systematically studied.The results show that the tensile,compression,bending and interlaminar shear properties of the hybrid composites in the carbon glass layer change significantly with the increase of carbon fiber content.The 0° tensile strength increases with the increase of carbon fiber content,while the tensile fracture zone decreases with the increase of carbon fiber content.The tensile strength at 90° showed an increasing trend.0° compression strength and 0° compression modulus increase monotonically.The bending strength decreases while the bending modulus increases gradually.The interlaminar shear strength fluctuates weakly and irregularly.The glass transition temperature rises accordingly.(4)The hygrothermal aging behavior of interlaminar hybrid composites with different hybrid ratios of carbon glass was systematically studied by water bath heating.It was found that the diffusion coefficient of water in the hybrid composites decreased with the increase of the hybrid ratio of carbon glass when heated in a water bath at 80? for 42 days.The retention rates of tensile strength at 0° and 90° are all above 72% and 42% respectively.The retention rates of 0°compression strength and 0° compression modulus are all above 64% and 92% respectively.The retention rates of flexural strength and flexural modulus are all above 52% and 92% respectively.The retention rates of interlaminar shear strength are all above 54%.The glass transition temperature decreased by 24% at the seventh day,and then increased to less than 12%.In the humid and hot environment,with the increase of time,some mechanical properties of hybrid composites in carbon glass layer tend to be stable when they decrease to a certain extent.Scanning electron microscopy(SEM)observation of the 90° tensile fracture section of the composite shows that the resin content of the hybrid composite between the carbon glass layers decreases obviously after wet and hot aging,and the internal void becomes larger,and the interface between the fiber and the resin is seriously damaged.