Full field methods and residual stress analysis in orthotropic material. II: Nonlinear approach

This paper is the second part of a work that analyses the problem of residual stress determination in an orthotropic material by the hole drilling technique combined with full field optical methods. Due to the complex behaviour of the material, two theoretical formulations capable of describing the displacement field in an infinite plate in tension with a hole have been proposed: a simplified one, which can treat only a subset of all orthotropic materials, and a general, much more complex one. In the first part of this work, it has been shown that by using the simplified formulation, it is possible to develop a linear least square approach to the residual stress identification problem capable of treating a large class of orthotropic materials. This second part shows that the same approach can be extended to the general case providing that a somewhat more complex, nonlinear algorithm, is acceptable.