Rubbing analysis and structural design for fan blade and case of aero-engine

Under abnormal loads, there is often a lack of data to describe the rubbing deformation and damage characteristics between the blade tip and the case of the wide-chord fan blade of aero-engines. The traditional theoretical calculation methods have large errors. To solve this problem, an explicit dynamic analytical model for the blade tip rubbing of a wide-chord fan was established. The calculation accuracy of the analytical model was verified by utilizing the test data of wide-chord fan blades and case. Based on the analytical model, sensitivity analysis of simulation parameters were carried out. The rules of blade deformation and case damage after the rubbing of the blade and case were obtained. The results indicate that the blade tip elongation is sensitive to rotor speed,and the increase rate of blade tip elongation is much bigger than the rotor speed.So the blade tip elongation at limited fan blade speed was considered in design. Suitable twist angle is an important factor of safe and dynamic performance demand.In the case inclusive area design, it is necessary to enlarge the safe margin to eliminate the influence of abnormal load. Choosing wear-resistant material with reasonable parameter is helpful to reduce the impact damage from fan blade. The proposed method can improve the accuracy of tip clearance control, and reduce the risk of rubbing and the damage of blade and case caused by rubbing.