engleski

The Compensation of Out-of-plane Displacements in Deformation Measurement by Grating Method

The paper presents a full-field optical grating method for the measurement of in-plane surface deformations, complemented with a compensation procedure of apparent deformation caused by out-of-plane displacement of measurement region. The compensation procedure is based on geometrical analysis of 3D displacement measured by stereophotogrammetry. The performed experiments show the important role of apparent deformations in the measurements, where perceptible out-of-plane displacements occurred. The proposed procedure compensates successfully these apparent deformations, also where the out-of-plane displacements are measured with smaller accuracy. Therefore 3D analysis can be carried out for the whole object, combined with the precise 2D grating analysis of few small interesting regions (for example region of high stress concentration). The proposed procedure enables the successful grating analysis of in-plane surface deformations of very small regions (for instance 1 mm2) also where significant out-of-plane displacements take place.

stereophotogrammetry; grating method; 3D optical measurement; displacements; deformations

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