The Analysis On The Stress Field Of Aircraft Wheel Hub And The Evaluation On The Life Span Of Safety Operation

The aircraft wheel hub is not simply combined with board and shell, but a revolving solid structure which resembles a combination of half shell and half board; it is also withstanding the ground load and other loads that transmitted through the aeolotropic elastomer tire. For the special structure and the complex stressed condition of wheel hub, it is nearly impossible to work out the stress distribution by using the fundamental equation solution to promote the stress analysis which deducted by the classics elasticity theory; meanwhile, a series of suppositions concerning with related components which has strained conditions or the stress distribution have been used by the traditional mechanics, so it is often get an approximate result. But in virtue of computer, there comes an efficient method which carries on the simulation to the working state of the wheel by using the finite element value computing.The finite element method must be adopted under the correct mathematical model premise, produced with an appropriate stress analysis and selected reasonable finite element computational procedure, thus the correct computed result can be achieved. Therefore, it is very important to establish the finite element model to carry on the stress field analysis to the wheel hub.In view of the characteristics of LS-129 wheel structure, this paper established a full-size finite element analysis model of no-brake and no-tire tube, which has been backed with "the Supplemented Criterion of Civil Transport Aircraft Wheel and Brakes Design Durability".This paper has simulated all sorts of boundary condition and the load that the wheel has endured in practical work through general finite element procedure ANSYS; and according to characteristics of the geometry non-linearity and non-compression when the tire in the condition of distortion, this paper turned the aeolotropic elastic material consideration into the isotropic hyperelastic material and calculated the stress field distribution of wheel hub under all sorts of operating modes; meanwhile, it made a contrast with an electrical measurement test result, which has achieved a more accurate estimated data and initially confirmed the accuracy of wheel hub finite element model.Then, this paper has introduced the fatigue damage evolution equation. By defining some material constants, the load cycle-index that produced when the wheel hub material enter the yielding state has been calculated; meanwhile by using the Linear Cumulative Damage Theory (the Miner theory), the life span of safety operation in the most disadvantageous spot of the wheel hub has been estimated, which has carried on the analysis and the appraisal to the model serviceability and practicability.This paper systematically represented an idea of the analysis on the wheel structure with the finite element analysis procedure, and calculated the load cycle-index by introducing the elastic fatigue damage evolution equation.To analyze the stress field of wheel hub with the finite element analysis procedure and to make a contrast with the electrical measurement result can not only been used to calculate the intensity and the rigidity of the new designed wheel hub but also been used to reduce the cost of the structure optimization design, which made it possible and optimistic for the computer to optimize the wheel structure.