Study of failure mode and failure load of a civil aircraft pylon double-layer fuse pin

Abstract

One of the key techniques to prevent serious accidents due to fuel tanks is the development of the engine pylon emergency separation fuse pin structure. By completing the round bar tensile test and the Hopkinson test, the material and constitutive model of a certain aircraft engine pylon double-layer fuse pin are determined. To study its failure mode and the failure load, the static strength failure tests of eleven conditions, as well as the finite element simulation, were carried out. The findings show that the failure mode is a shear failure, and the clearance size affects the failure sequence. When comparing the failure load obtained by simulation and test with the designed failure load, the three show a consistent trend with an average error of less than 10%. Furthermore, when the clearance size is less than 2 mm, the strength of the inner pin can be entirely superimposed on the outer pin, and the shear failure load is basically the same as the single-layer fuse pin with the same cross-sectional area. The study’s findings may serve as an important reference for the new structural design of the emergency separation fuse pin.