Strain Measurement Of High-speed Rotating Blade Based On Digital Image Correlation Method

Digital Image Correlation(DIC)is a non-contact optical measurement technology,which is widely used to measure the full-field displacement and strain of an object under force,and has the advantages of non-contact full-field measurement,high visualization and high measurement accuracy.In this thesis the application of DIC in the strain measurement of high-speed rotating blades is studied,and an experimental platform for the strain measurement of high-speed rotating blades is built.Based on DIC a strain image processing strategy of high-speed rotating blades is proposed,which solves the problem of large-angle’s precise matching in the measurement of large-angle rotating deformation.The blade strain measurement at 10000 rpm is realized.The specific research contents are as follows:(1)A high-speed rotating blade strain measurement experimental platform and a low-speed rotating blade strain measurement experimental platform are built in this thesis.The platform consists of a power drive module,an imaging module and a data processing module,which can achieve the acquisition of blade strain images at 10000 rpm and3000 rpm respectively.(2)A DIC-based strain processing strategy for high-speed rotating blades is proposed,which mainly includes: image enhancement,two-step angle matching algorithm and DIC processing.This strategy can accurately obtain the restoration of the strain field of the blade at any angle.(3)A 3000 rpm blade strain measurement experiment is carried out based on the designed low-speed rotating blade strain measurement platform.The experimental results are compared with the simulation results to verify the reliability of the designed system and analyze the factors affecting blade strain.(4)A 10000 rpm blade strain measurement experiment is carried out through the high-speed rotating blade strain measurement experimental platform,and the obtained blade reference image and deformation image are restored to the strain field through the data processing strategy of this thesis,and compared with the results of ANSYS blade simulation.The results show that the system proposed in this thesis can measure the strain and reduce the strain field of the high-speed rotating blade at 10000 rpm or below.