Preparation, Characterization And Evaluation Of Needle Punched/I Fiber Coupling Reinforced Composites

With the development of the aerospace field,the requirements for important components of aircraft are becoming higher and higher.The reinforced composite materials prepared by three-dimensional needle punching have been difficult to meet the conditions of hypersonic flight.? fiber implantation is a new type of suture technology.Based on this background,the research puts forward the combination of acupuncture technology and ? fiber suture technology,and puts forward and carried out a new structure of acupuncture/? fiber coupling reinforced composite material around the main line of "process-equipment-performance" integration.A series of experimental studies were carried out on preparation and performance characterization.Aiming at the key technical requirements for the three-dimensional automated preparation of acupuncture/? fiber coupling reinforced preforms,an ? fiber implantation robot system based on a 6-joint robot was constructed,and the mechanical structure design of the ? fiber implant head and the integration of the control system were completed.And carried out relevant experimental verification,proved the feasibility of the system.At the same time,the robot trajectory planning method for automatic stitching of ? fibers for needle-punched preforms is studied,and the matching mechanism of different sizes of yarns with different types of hollow needles in the experiment is proposed.Prepared acupuncture/? fiber coupling reinforced composite material,and studied its interlayer connection performance,bending performance and tensile performance under different stitching parameters through experiments;experimental data results show that the implantation of ? fiber significantly improves the composite The interlayer performance of the material;the ? fiber with a certain head length can significantly improve the interlayer performance of the composite material;there is an obvious proportional relationship between the failure load value and the amount of ? fiber implantation.At the same time,experiments show that the implantation of ? fibers has no significant effect on the tensile strength and flexural strength of the needle-punched structure composite material,and the performance change rules about the size of the ? fiber bundle and the length of the ? fiber head are obtained.Carried out experimental research on the impact resistance of the needle punched/? fiber reinforced composite material under different stitching parameters,and observed the damaged area using ultrasonic C-scan and profiler,and found that the energy absorbed by the material is similar to the value of ? fiber.The implantation is independent of the interval,density and pattern of sutures.When subjected to the same impact,the narrower the interval of ? fiber implantation,the smaller the damaged area;when the implantation amount increases,the damaged area decreases with the implantation amount.The thermophysical properties of acupuncture/? fiber coupling reinforced composite materials prepared by preform structures with different suture parameters were studied.The preform structure before and after ? fiber implantation and under different implant parameters and the microstructure of the matrix were obtained.The specific heat capacity has almost no effect;the axial thermal conductivity of the composite material of each structure is slightly lower than the corresponding radial thermal conductivity,but the gap is very small,and the radial and axial thermal conductivity of each parameter material varies with the size of the ? fiber bundle and The changing law of ? fiber head length.