Use of Graded Laser Scanning to Generate Efficient Boundary Element Meshes

Abstract

This thesis presents an approach which combines a reverse engineering technique with boundary element stress analysis, by generating a graded mesh to improve the simulation efficiency. A rectangular metal plate, a bar of a circular cross section, a gas turbine blade and a steam turbine blade were scanned at different resolutions using a (non-contact) laser scanner measurement to obtain the point clouds. Meshes of each object were generated in Rapidform and directly used in a boundary element stress analysis. In addition, the steam turbine blade was scanned using different scanning resolutions. From this, a graded mesh model of the blade was generated and then efficient boundary element stress analyses were performed. An application of a freeform surface reconstruction of a blade surface is also given. Also, several Matlab programs were written to repair the edges and the cylindrical surface of the meshes.