Crack tip strain on ship and in situ measurement in shipyards

The paper presents the application extent of procedures for measurement deformations on ships. The actual deformation distribution was measured on the surface of the specimen by the optical grating method (OGM) parallel to the CTOD measurements. Displacements are actually measured with two cameras, i.e. stereometric method. The stereometric method for monitoring deformation is presented with an example of application. The deformation of the surface was measured by recording the displacements of the optical marks, and captured in such a way that the 3D coordinates are connected with picture coordinates. Further calculation of the ship deformation gradient is possible by using the theory of large deformations, which allows large plastic deformations as well as rigid ship motion. Further development of research is focused on constant deformation and damage monitoring in order to take full advantage of computer technology