Analysis For Temperature Field And Thermal Stress Of Resin Matrix Composite Patches During Curing Process

The composite materials have the advantages of light weight, high specific stiffness, good elasticity, high strength, high fatigue strength, easy molding and corrosion resistance etc. After years of development, the application of composite developed from the original secondary structure to the current main load bearing structure. Thermal curing is one of the main ways of molding of composite material. The complex temperature distribution and change are generated inside of the patch during the thermal curing process, because of the internal exothermic reaction and the external heating environment. The complex temperature field will affect the internal uniformity of curing and thermal stress, which affects the quality of curing.In this dissertation, the temperature field and thermal stress of the3234/T300B resin matrix composite patch during the curing process are studied. The research results can provide numerical basis for reducing the thermal stress and optimizing the curing process, thereby improving the quality of curing. The main contents are:(1) The resin matrix composite repairing method and process are studied by experiment and the curing process temperature curve is designed with the aid of vulcanizing machine.(2) The physical model and mathematical model of composite patch are established, and the temperature field distribution of the patch of different shapes and different thickness are discussed. The results show that the temperature and degree of cure at different points inside the patch change with time in the same trend.(3) The effects of heating rate, patch thickness and patch angle on the temperature field distribution of the patch are analyzed. Curing begins earlier and the curing time becomes shorter with increasing heating rate; curing begins later and the curing time becomes shorter for thicker patch because of the more substance participating in reaction; the peak value of temperature at non-center points become higher and curing rate become faster with increasing the scarf angle for thick patch.(4) The effects of the thickness, heating rate, patch angle of the trapezoidal patch on the internal thermal stress of the patch during the curing process are also analyzed. The thermal stress inside the patch increases with increasing heating rate and patch thickness. While the thermal stress inside the patch decreases with increasing the scarf angle.