| Carbon/epoxy composites are widely used in the aerospace field as they provide high specific modulus and pecific strength and designability.Due to the external environment and the internal material itself,the composite material will produce a variety of impact damage in the course of use,these damage will affect the performance of its normal use,and need to be repaired.In this paper,by studing the curing agent and the impact of the repair and repair technology,combined the technology of rapid curing with the repair of composite materials,so as to achieve the purpose of rapid repair of composite materials.In this paper,carbon fiber/epoxy composites were prepared by hand lay-up process according to [0/45] and [0/90],and study the various factors that affect the performance of the composite.Synthesis of a room temperature fast curing agent for composite repair.The effects of monomer,synthesis temperature,synthesis time,diluent and accelerator on the curing properties of the curing agent were analyzed.The impact and compression tests of 6,8 and 10 layers of carbon fiber composites were carried out to study the damage of composite materials by impact warheads of plane warheads,semi-elliptical warheads and hemispherical warheads.The impact energy and composite Material damage relationship.The ultrasonic C-scan was used to detect the composite material after impact,and the area and depth of the damage were determined.The compressive strength recovery rate and the mass increase rate of the composites were studied by using one layer,two layers and three layers of carbon fiber.The main conclusions of this paper are:1)With the continuous addition of diluent,the compressive strength of the composites increased first and then decreased.When the 5% diluent was added,the composite mechanical properties were the highest.The composite materials containing 6 layers,8 layers and 10 layers of carbon fiber cloth were prepared by epoxy resin(E51),triethylenetetramine(TETA)and diluent 660 at 100: 12.43: 5 ratio.[0/45] and [0/90],the mechanical properties of the composites are not obvious and the resin content is basically the same.2)The optimum ratio and optimum synthesis process of synthetic room temperature curing agent were obtained by orthogonal test and related performance.The ratio is(molar ratio)n(phenol): n(paraformaldehyde): n(triethylene tetramine):n(Thiourea)= 1: 1: 1.7: 0.9.The reaction time was 2 h and the temperature was110 ?.The addition of diluent 660 greatly prolongs the cure time,and the addition of the accelerator DMP-30 reduces the mechanical properties of the epoxy resin cast.3)Different impact warheads will produce different shock damage sizes for composite materials under the same energy.With the same impact energy,the more carbon fiber content in the composite material,the smaller the damage;the same carbon fiber content of the composite material by the impact of the larger energy,the more serious damage;with the increase of impact energy,the damage area and depth of detection are more and more obvious.The curing conditions of epoxy resin are :curing temperature is 25 ?,curing time is 2 h,rapid curing at room temperature has been achieved.4)6 layers of carbon fiber reinforced composites were repaired by 8J,and the repair effect was better,after a layer of carbon fiber repair strength recovery rate of60%,the quality increase rate of 3.75%;after two layers of carbon fiber repair strength recovery rate of 71%,the quality increase rate of 6.17%;after three layers Carbon fiber repair strength recovery rate of 74%,the quality increase rate of 12.55%.Composites repair two layers to ensure the strength recovery rate while controlling the quality increase,more reasonable.Compared with triethylenetetramine,fast curing agent used in this paper to ensure the strength of the recovery under the premise of curing in 2 h,to achieve the purpose of rapid repair. |
PDF Full Text Request