Research On Structure Sealing Performance Of Metallic Integral Fuel Tank

Integral fuel tank is widely used in modern aircraft structure. In the past, the sealing performanceof the integral fuel tank was usually obtained through experiments. Due to the limitation of money andtime, the number of integral fuel tank test components can only be one or two. There are so manyfactors which have influence on the test result that the test result gotten from such a small experimentalsample would not reflect accurately the actual sealing performance of the integral fuel tank. In thispaper, through the analysis of failure mode of the integral fuel tank, some sealing design problems of itare investigated.The sealing performance of the integral fuel tank depends mainly on the fatigue life of the sealant.In this research, fatigue tests were carried out on new sealant and old sealant which has been used forfive years, respectively. Fatigue lives at different strain levels were acquired.In order to ensure the leakproofness of the integral fuel tank, it is required that the relativedeformation at the joint is within the allowed deformation of the sealant. According to this, a designcriterion for deformation of the sealant is proposed. To verify this criterion, firstly the relativedeformation at the joint of the integral fuel tank was calculated making use of a Global-Local finiteelement method; secondly, an analog component of the integral fuel tank was designed and tested underfatigue load. The test result demonstrates that the design criterion for deformation of the sealant isreasonable; finally, employing this criterion, the sealing performance of a wing integral fuel tank of acertain aircraft was analyzed. The analysis result has been adopted by practical engineering design.