This work analyzes the problem of residual stress determination in an orthotropic material using the hole drilling technique combined with non-contact, full field optical methods. Due to the complex behavior of the material, first a solution algorithm for the isotropic case is analyzed, then the procedure is extended to solving the more complex problem. In the first part of the work, the simplified Smith-Schajer solution to the through-hole problem for an orthotropic material is analyzed, showing that the same linear least square approach used in the isotropic case applies to a large set of orthotropic materials; based on this analysis a simple residual stress measurement algorithm is developed using either analytical or numerically estimated calibration coefficients. In the second part of the work, the general solution is discussed: since in this case the simplified Smith-Schajer solution cannot be used, the Lekhnitskii's analysis of the through-hole plate in tension is introduced and extended to handle residual stresses. On this basis a solution algorithm using the nonlinear fit of the theoretical displacement field capable of treating all the orthotropic materials at the cost of a more complex numerical procedure is proposed. The performances of both algorithms are tested against numerically generated noisy fields and experimental ones and show a good reliability and accuracy. © 2007 Elsevier Ltd. All rights reserved.
Baldi, A. (2007). Full field methods and residual stress analysis in orthotropic material. I Linear approach. International Journal of Solids and Structures, 44(25–26), 8229–8243. https://doi.org/10.1016/j.ijsolstr.2007.06.012