Reliable alignment method for blade shape analysis considering its blend and twist deformation

The reliable alignment of turbine blade measurement data and its CAD model is a key step for turbine blade geometric shape analysis. In order to improve the reliability and robustness of the blade model alignment process, a blade model alignment method which takes into consideration its blend and twist deformation is presented. A pre-transform function is introduced to the Iterative Closest Point model alignment method for establishing the blade model alignment objective function. Through slicing the blade model and analyzing the blend and twist deformation, the blade blend and twist deformation curves can be generated and adopted to guide the model alignment process. Simulation data of the blade with blend and twist deformation and a set of real measurement data of a turbine blade by a Coordinate Measuring Machine are used to verify the method. Experimental results show that by using the proposed method, the model alignment reliability is improved and the possible failure of the alignment process caused by the blend and twist deformation can be avoided.