Seal Failure Analysis And Test Verification On The Integral Fuel Tank Of Composite Wing

The integral solidification molding technology of composite materials is becoming more and more mature.When it is used in the structural design of the integral fuel tank of the wing,the number of parts and the sealing position can be greatly reduced.But the anisotropy of the composite material can easily lead to the stress concentration in the area near the fastener,and the performance requirement of the sealant is more severe.The nonlinearity of sealant material increases the difficulty of the integral fuel tank seal design,which brings difficulties to the failure analysis.The sealing failure of composite wing integral fuel tank is studied in this paper.(1)This paper introduced different constitutive models of sealant to select the suitable model and material parameters.According to the failure problem of the sealant,the paper predicted the possibly growth direction after the crack propagation by using the Mooney-Rivlin constitutive model and the J integral theory of crack propagation.The cohesive zone model were used to simulate the crack initiation and expansion of the faying surface's sealant,and to obtain the failure analysis of it.(2)The integral oil tank structure model of the composite wing was analyzed and the static test of the integral fuel tank of the wing was designed.Compared the simulation result with the test data the displacement and strain of the whole model are obtained.It provided a reference for ther analysis of the sealant structure of the integral fuel tank.(3)Based on the analysis of typical L-type connectors,the failure process and the basis for judging the damage were obtained from the filleting and faying surface on the sealant model.The high strain region sub-model of the integral fuel tank of the wing was constructed from to simplifying the bolted model of the integral fuel tank.The displacement and stress values of the sealant at the key assessment structure were obtained and to determine whether the sealant was failure or not.A verified seal failure method was provided for the seal design of the integral fuel tank of the wing.