Research On Fatigue Life Analysis And Optimization Of Landing Gear For A Large Amphibian Aircraft

Large amphibian aircraft was developed for the first time as the special use of large civilian aircraft in China, it has the capability of taking-off and landing both on the land and water.As one of the main functional assembly units, Landing gear is a key part that affect the safety and reliability of the aircraft flight. Under the cyclic loading, fatigue damage is the major form for the failure of Landing gear, so the FCP parameters of the aircraft is closely related to the fatigue property of the Landing gear. Guided by the theory of fatigue life analysis, this paper carries research on fatigue life analysis and optimization of the front and main Landing gear for a Large Amphibian Aircraft,with the use of advanced virtual prototype co-simulation technology, finite element analysis calculation method, the fatigue life calculation and optimization software.We divide Landing gear meshes and set up typical load cases by the finite element pre-treatment software Hypermesh, calculate the distribution results in the finite element calculation software NASTRAN, carry on research in Landing gear overall structure fatigue life through the fatigue analysis software Ncode Designlife.What’ more, on the basis of the research in the overall structure fatigue life,we carry out research on fatigue life for the the key structure components in details.That is to say,we set up the rigid flexible coupling model of the front landing gear to get the node forces of all connected parts through the multi-body dynamics software LMS Virtual.Lab, then set up the models one by one for each parts in Hypermesh to calculate the stress distribution of the various parts under unit conditions, finally obtain the more accurate fatigue life of each parts。At last, with professional optimization software Optistruct which based on the fatigue life structure optimization technology, we do shape optimization on the positions of Landing gear with little fatigue life to make further improvement. The results of fatigue life calculation verify that the front and main landing gears of the large amphibian aircraft meet the requirements for the design based on fatigue life.What’s more,the results provide a guarantee that the front and main landing gears of the large amphibian aircraft will be safe in its fatigue life. The research on structure optimization provides effective ways for the optimization of large landing gear based on fatigue life.