Impact Strength Study And Impact Test Design Of Fuse Pins Of Aircraft Pylon

The emergency breaking away design of engine pylon of civil aircraft refers to an effective breaking away technique of pylon structure connecting engine and wing in emergency landing conditions.The devise concept is to design the connectors of the joints connecting pylon and wing as emergency breaking away components(fuse pins).By adjusting the structural strength of the fuse pins of the pylon joints,the failure path and breaking away attitude of the engine pylon is regulated and the engine pylon can be safely broken away from the wings.The emergency breaking away techniques of engine pylon is an effective way to protect passengers from fire and explosions caused by wing tank damages The fuse pin is the core of emergency breaking away design and the failure modes and fracture loads of fuse pins of the pylon joints directly affect the realization of the emergency breaking away techniques.Therefore,it is necessary to study the fracture process and impact loading behaviors of fuse pins with numerical simulation methods and impact failure test.Based on the fuse pins of the IPS(integrated propulsion system)engine pylon of C919 aircraft,dynamical finite element models without consideration of temperature and thermal-mechanical coupled finite element models of the fuse pins are established respectively,the thermal-mechanical coupled simulation models are selected as the dynamical simulation models according to the simulation results of the two simulation method.The failure modes,energy absorption and breaking loads of the fuse pins are discussed.Boundary conditions is set on the basis of the airworthiness regulations and emergency landing conditions to study the influences of the impact velocity and impact angle on the fracture process of fuse pins.The angle ranges of fuse pins of each joint to realize the breaking away design are predicted.According to the engine pylon loads and supporting forms of fuse pins,a set of free-falling impact loading test system is established to study the effect of impact loading rate on the failure mode and the breaking loads of fuse pins.The test program gives the improve method of the test fixture of fuse pins.By using the finite element method,the strength of the test bench and fixture is checked and the modal analysis of the test bench is carried out,which verifies the feasibility of the test system.