This paper presents the results for the real-time measurement of surface deformation of rotating elements. A digital image correlation technique is used to estimate the surface displacements and strains. Speckle patterns are spray painted on the surface of interest and digital images taken before and during deformation caused by rotary motion. The digital image of the deformed blade is taken by freezing the speckled pattern with the help of a stroboscope. The technique provides several advantages over traditional methods in terms of obtaining whole-field deformation profiles, a non-invasive measurement scheme, and a simple and economical set-up. Results are presented for 1D uniform strain as well as 2D strain in a region next to a hole in a rubber specimen that is rotated at different speeds. The scheme presented in this paper can also be extended to measuring out-of-plane deformation by the use of an additional camera. The proposed technique can be used for measuring deformations in turbine blades, helicopter blades, or any other rotating elements.
2002 SEM Annual Conference & Exposition on Experimental and Applied Mechanics
Maudlin, Jay; Mahajan, Ajay Mohan; and Chu, Tsuchin P., "Real-time Measurement of Surface Deformation of Rotating Blades" (2002). Mechanical Engineering Faculty Research. 557.