The Research Of Fan Repair Digital Modeling For The Aviation Engine

Aero-engine blade always works under poor environment with high temperature and high pressure, not yet reached the life of the engine blade damage accidents often occur.Deformation of the turbine blades to detect or repair poor can not lead to a lot of air failure, so how to detect and repair aero-engine blade turns to be more and more important. At present,the blades repairing technology are not be grasped fully. Because of improper repairing, some blades which can continue to be used are being abandoned. That will not only increase the cost of aircraft maintenance, but also cause unnecessary waste.In this dissertation, used to analytical processing of the blades three dimensional spot cloud data is acquired with Leica Laser Tracker. And then a digital modeling of aero engine blade can be founded. At last make the digital repair for the defective model.In order to accurately obtain the surface shape of the measured object, the clouds which are measured by Laser Tracker have lots that do not need. So Guass filter is used to reduce the noise point cloud and streaming of smooth. And considering the feature of changing angularity, simplify the point data using angularity method, also a variable step forward and in curvature of leaf method was raised.After getting the simplified point cloud data, firstly, chose the best result of the edge of point cloud based on curvature, and then interpolated the digital model of the edge of turbine fan. Secondly, use the method of B-spline surface approximation to fit the surface of blade.Finally, put the envelope and surface together, based the blending surface, the digital model of blade can be established.According to the pattern of blade, different methods are chosen to inquire the damaged area. If the patterns are same, seed grid method is applied to inquire the damaged area, then boundary treatment method is used to complete digital repair of damaged area. If the patterns are different, analyzing curvature of the envelope is applied to inquire the damaged area, and use then curve and surface interpolation method to repair the damaged blade.Through the test, it proved that the digital model had good the light and accuracy of aero engine blades.