Study On Strength Of Fuse Pins Of Large Civil Aircraft Pylon

Emergency break-away fuse pins of civil aircraft pylon are the connection structure connecting engine pylon joints and wings.The engine thrust load is transmitted from engine to wings through joints and fuse pins of pylon structure.On the one hand,plastic deformation and damage should be avoided under required static loads.On the other hand,fuse pins should be destroyed immediately after absorbing certain energy and the failure model should be simple and clear to satisfy the emergency break-away techniques.Therefore,it is of great importance to study the failure modes and fracture loads of fuse pins.Based on the fuse pins of the pylon of C919 aircraft,using the program ABAQUS,uttering explicit central difference method,determining the constitutive model and damage model and the parameters,choosing Linear reduction integral element of hexahedron and its size,confirming the loading time which can make the calculation efficient and accurate,the finite element model of the fuse pin structure is founded.The finite element model is verified,showing that it is reasonable,accurate and reliable,lying the foundation of the afterward simulations.The effects of the installation clearance on the failure modes and fracture loads of fuse pins are studied,the results shows that the installation clearance has little effect on the fracture loads,but has remarkable effect on the failure modes of fuse pins.The effects of the outer diameter thickness ratio on the failure modes and fracture loads of fuse pins are studied,the quantitative relation of fracture loads and inner diameters and that of fracture loads and outer diameter thickness ratio are gained,and the reasons are analyzed uttering theoretical approaches.According to the engine pylon loads and supporting forms of fuse pins,a static test scheme aiming at studying the effects of the installation clearance and the outer diameter thickness ratio on the failure modes and fracture loads of fuse pins is established.The tongs and a set of tension switch device are designed and their strengths are checked uttering finite element method,verifying the feasibility of the test scheme.