Three‐dimensional deformation measurement of aero‐engine high‐speed rotating blade surface based on stroboscopic structure digital image correlation method

Abstract

Under the working conditions of aero-engine, the three-dimensional composite deformation of the blade is caused by the centrifugal force generated by high-speed rotation and the load generated by gas scouring. Aiming at the problem of three-dimensional composite deformation on the surface of aero-engine blades under high-speed rotation, a three-dimensional deformation measurement method based on stroboscopic structure digital image correlation method is proposed, and a method for eliminating rigid body displacement induced by the trigger error of the stroboscope is proposed. First, the laser trigger-stroboscopic irradiation system is used to freeze the high-speed rotating blade under a specific phase. Then, the binocular vision system is used to collect the surface image of the rotating blade. Finally, the digital image correlation method is used to measure the surface deformation field of the high-speed rotating blade. In this paper, the experimental platform is built and the displacement field and main strain field of the blade surface under high-speed rotating state are measured. The experimental results show that the stroboscopic structure digital image correlation measurement system and method have realized displacement measurement accuracy of 2 μm and strain measurement accuracy of 100 μɛ and have realized the surface deformation measurement of the ducted turbine fan blade under the condition of 6000 rpm (CFM56-7 engine N1 speed). The results show that the method is effective and can provide a reliable measurement method for the deformation measurement of high-speed rotating blades in large engine manufacturing enterprises such as Aero Engine Corporation of China.