Mechanical Properties Of Glass Fiber/Vinyl Ester Composites Toughened By Non-woven Fabrics

Ningxia is a gathering place of China's solar power and wind power industries.The GF/VE composite material with many advantages such as light weight,high strength,corrosion resistance and low price is an ideal material to realize the light weight of equipment in the energy industry.However,composite materials are prone to lamination damage.Adding non-woven fabric between layers can significantly improve the lamination resistance of composite materials,and has a significant impact on the mechanical properties of opening holes.This paper focuses on the following aspects of the pore opening mechanical properties of GF/VE composites toughened by non-woven fabrics:(1)Using vacuum assisted molding(VARI)process preparation of interlayer join PEs,TPU,PA,EVA four kinds of non-woven fabrics of GF/VE composites,the interlayer to join different non-woven composite laminate tensile,bending performance and I interlaminar fracture toughness was studied.Interlayer in non-woven fabric of GF/VE composites interlaminar fracture toughness increase obviously,join the PEs,TPU,PA,EVA,respectively,the mode I fracture toughness of composites increased by 142%,103%,46%,45%,analysts say the reason may be that non-woven melted in the crack surface form of fiber bridging,it at the crack tip stress shielding effect,makes the induced crack needed for further expansion of applied load increases.The fiber volume content decreased and the thickness increased,resulting in a decrease in the tensile and bending strength of GF/VE composites.(2)Select TPU non-woven fabric with better reinforcement and toughening effect and add it to the GF/VE composite layer,and perform the opening mechanical properties of the laminate(open hole stretching,open hole compression and filling hole stretching,filling hole compression)Based on the research,and based on the Hashin criterion,[0°/45°/90°/-45°]laminated composite perforated plates were subjected to failure analysis.The laminate with TPU nonwoven fabric showed good interface adhesion.Open hole stretching,open hole compression,filling hole stretching,and filling hole compression strength have all been improved.[0°/45°/90°/-45°]The open-cell tensile failure mode of 2s-layered GF/VE composite is the tensile failure mainly in the direction of 45°;the compression of the open cell is transverse through the center of the hole Failure;the shear failure occurs when the filling hole is stretched through the center hole,and the compression failure mode of the filling hole is also the compression failure that occurs horizontally through the center of the hole.(3)Based on the L9(34)orthogonal table,four factors including width-to-diameter ratio,end-to-diameter ratio,preload,and modified materials were selected,and three levels were selected for the four factors.The multi-factor synergistic effect on GF/VE composite materials was studied The single nail double lap bolt connection performance of the laminate,the order of the four factors affecting the strength of the GF/VE composite single nail double lap bolt connection is the width-to-diameter ratio,end-to-diameter ratio,pre-tightening force and interlayer addition Non-woven modified materials.The optimal level of each factor can be determined according to the average value of the index results corresponding to each level of each factor.The optimal level combination is a width-to-diameter ratio of 2,an end-diameter ratio of 6,and a preload force of 9 N·m.Add TPU nonwoven fabric modified composite material sample between layers.Through the research in this paper,it provides a valuable reference for the nonwoven fabric reinforced and toughened composite materials,and provides useful theoretical and experimental support for the overall structure design of the composite materials.