Efficiency of image correlation photogrammetry technique in measuring strain

Strain is one of the basic engineering properties by which materials can be defined, the elastic modulus of any material being derived from the stress-strain curve for a specific material. Strain measurements are also used in examining the efficiency of some structural components, such as composite members, for which the strain indicates the slippage level. A common method of measuring strain is by attaching strain gauges at the locations at which it is necessary to capture the strain, but the disadvantage of this method is that it is not efficient for large-scale elements. The image correlation photogrammetry technique eliminates the need to attach strain gauges on large structural members, and high-speed cameras are used to capture the movements of artificial dots on the structures. However, this method becomes inefficient for large-scale members, is that the manufacturer's specifications for the technique limit the use of random manual dotting, which makes it time-consuming. A new method of dotting is proposed in this study which involves randomly spraying the structural element to create small dots. The proposed method is compared with the strain gauge readings, the results show the efficiency of the proposed method and can be recommended for researchers and engineers.