Influence of Different Random Pattern Creation Forms on the Results of Experimental Modal Analysis Performed by High-Speed Digital Image Correlation

In this contribution an influence of random contrast patterns creation on the quality of the obtained results of experimental modal analysis performed by high-speed digital image correlation is described. Three common forms of random pattern creation were investigated. While the first form was presented by the black speckles printed on white matt vinyl foil and bonded on the sample surface, in the second and the third case, respectively, the black speckles were sprayed on white sprayed sample surface or on paint white one. For the purposes of modal parameters estimation in the form of natural frequencies, mode shapes and damping ratios the program called Modan3D, developed in the authors department, was used. The results obtained by Modan3D were compared with the results achieved by system Pulse specialized for vibration analysis