A Hybrid Moire-Interferometry and Finite-Element Method Based on a Variational Principle Minimizing Experimental Measurement Errors. Case of Elastic-Plastic Deformation Field.

Abstract

In a previous study, for the case of elastic deformation field, the authors have developed a hybrid experimental-numerical method based on a variational principle minimizing experimental measurement errors. In this stydy, for the case of elastic-plastic deformation field, first, an incremental variational principle is derived to minimize the errors associated with a full-field displacement measurement such as moire interferometry. Next, on the basis of this variational principle, a new hybrid moire-interferometry and finite element method is developed for the case of elastic-plastic deformation field. The present hybrid method demonstrates automatic detection and elimination of the measurement errors and smooth visualization of stress and strain contours. Furthermore, the present hybrid method automatically achieves the path independence of the T* integral, restoring the path-dependence caused by the measurement errors. This paper provides the foundation of an intelligent measurement and visualization of displacement and stress fields in actual structural components.