Study On The Anti-Leakage Of Carbon Fiber/Epoxy Composites For Cryotank

The goal of future aerospace vehicles has gradually been towards cleaner,reusable,single-stage orbiting,etc.The manufacture of cryotanks has become a key technology in aerospace engineering.The resin matrix carbon fiber composites have high specific strength and are used as a material for manufacturing cryotanks.Can greatly reduce the launch cost of the vehicle,therefore,the all-resin-matrix carbon fiber composites has become a key research object.Liquid hydrogen is very easy to leak in the composite tank,which is a problem that needs to be solved urgently.This topic studies the leakage resistance of composites from the three aspects of matrix,reinforcement materials and improved methods,so as to reduce the leakage of composites.In order to study the effect of curing defects on the leakage of epoxy resin,E51 epoxy resin with different defects was prepared by mechanical stirring method,AM8927 epoxy resin with different curing degrees was prepared with different systems and the curing degree was tested,using helium mass spectrometry The leak detector characterizes the leakage of the resin and found that the higher the internal porosity of the resin and the larger the pore diameter,the higher the leakage of the resin;the higher the curing degree of the resin,the lower the leakage of the resin.In order to study the effect of the laminate structure on the leakage of composite materials,different types of fibers and fibers of different structures were selected to prepare composite laminates with different laminate structures,and the interface properties of different types of fibers and the resin matrix were studied.Helium mass spectrometer leak detector characterizes the leakage of composite laminates.It is found that the better the bonding performance between fiber and resin,the lower the leakage of composite laminates;the more complex the fiber laminate structure,the lower the leakage of composite laminates.In order to study the improvement method of composite material anti-leakage,the composite material laminated board was doped with different mass fractions of nanosilica,and polyimide film layer and alloy aluminum foil layer were added,and the helium mass spectrometer leak detector was used to characterize the leakage of composite laminates.To improve the leakage of the composite laminate,a certain amount of nanosilica can reduce the leakage of the composite laminate,and an excessive amount of nanosilica will increase the leakage.The leakage resistance of alloy aluminum foil is stronger than that of polyimide film,but the bonding ability of alloy aluminum foil and epoxy resin is weaker than that of polyimide film.