Discrete Data Points Of The Turbine Blades Surface Reconstruction

Surface reconstruction is one of key techniques in reverse engineering . Based on Unorganized discrete points come from finite element analysis triangular mesh on exterior surface of the aeroengine hollow turbine blade ,this dissertation studied some related problems , such as scattered data preprocessing, quadrangle partition and surface reconstruction technology. The main research works of the dissertation are as follows:1) Preprocessing technology of unorganized diserete points: The relative research works were focused on two issues: boundary extracting from unorganized discrete points and generating of original surface, boundary extracting were realized on the basis of rules that disctete points are on the form of triangular mesh and the number of neighbor triangle of border points and inner points are different. Original surface is formed from boundary curve and section curve using the redevelopement interface of UG.2) Quadrangle partition technology of unorganized diserete points: The curveness-based mesh generation of free-form surface, compress of vast discrete points and quadrangle partition are researched. The adaptive mesh generaion of exterior surface of turbine blade is achieved by using self-organizing method. Quantity of vast discrete points are compressed to a appropriate number and these points are partitioned to different quadrangle for the reason of surface approximation using NURBS.3) Surface reconstruction technology of unorganized diserete points: Reconstruction and connection of surface are researched. The weakness of interpolation method relative to approximation method is analyzed from viewpoint of practicability. Approximation method based on QURBS(Quasi-Uniform rational B-Spline) is adopted and a iterative algorithm is introduced to improve the precision in the paper. Method of edge curve Replacement is used to reach GC0 connection of two surface. Method same as Bezier GC1 connection is used because QURBS surfacehas same geometrical property as Bezier surface on the boundary.