Experimental analysis of the deformation of convex cylindrical surfaces

The described method is based on the moiré technque. By applying a special stripping film with a copied grid to a convex cylindrical surface, it is possible to express the equations of the deformed as well as the undeformed grid. By using the double-exposure photographic technique, a field of moiré fringes will be obtained, which gives information of the component perpendicular to the direction of observation of the deformation vector in the plane perpendicular to the axis of revolution. By observing two different directions α₁ and α₂, the experimental data yield the calculation of the displacement vector. The application of the derived method and its reliability will be demonstrated by several examples. The method does not require highly expensive laboratory equipment and is especially useful for engineers in consulting and structural design.