A technique of the normal and tangent displacements' determination in thinwalled structures-shells on the basis of the focused images of Fl Holographic Interferometry is developed.(FIHI). The used approach allows with the same satisfying accuracy to determine the displacements components in one experiment , by the unified optic scheme, on one hologram. The high sensitivity to three components of the displacement vector on the structure's illuminated surface is achieved on the account of that on one photoplate two interferential pictures take place, which cany the separated information about the normal and tangent displacements on the surface of the shell or plate. In the kind of examples the result of the investigations for the round plate and the cylinder shell under the P force were presented, the interferograms and speckle-photographs were obtained, on the basis of which the interpreting was produced. Using the relationships of the classic theory of plates and shells(Kirhgoffs-Liav's theory) and the obtained three displacements components, preliminary approximated by the degree polynomials of the high degree by the method of minimum squares on the PECM, the deformations on the illuminated surface of the object were determined. And by the specklephotograph the sunimary deformations from bending and tension were obtained, and by the interferogram-the bending components. Then the separation of deformations to the moment and membrane was done , the dependencies of the deformation levels on the illuminated middle and nonilluminated surfaces were constructed. Such approach to the investigation of the thinwalled shells highly expand the application of the hologram Interferometry methods.
Keywords: three-exposure, focused images, holographic interferogram, spatial structures, displacements, deformations, approximation.