Eventos Anais de eventos
MECSOL 2022
8th International Symposium on Solid Mechanics
On the use of recovered stresses to improve the accuracy of the contour integral method in the computation of stress intensity factors
Submission Author:
Rafael Lins , SP
Co-Authors:
Rafael Lins, Mariano Arbelo, Francisco Alex Monteiro, Sérgio Cordeiro
Presenter: Rafael Lins
doi://10.26678/ABCM.MECSOL2022.MSL22-0110
Abstract
This work aims to assess the effect of the replacement of the raw stresses by the recovered stresses on the computation of stress intensity factors (SIF's) using the contour integral method (CIM). The raw stresses are computed by means of two distinct methodologies: the generalized finite element method (GFEM) and the stable generalized finite element method (SGFEM). For both methods, the adopted enrichment functions aim to emulate the discontinuities introduced by the crack and also to represent the singularity effects nearby to the crack tip. Furthermore, in the SGFEM, these enrichment functions are slightly modified to overcome some drawbacks commonly associated to GFEM, like decrease of convergence rate due to ill conditioning of the stiffness matrix. The recovered stresses, in turn, are obtained using a procedure based on a locally weighted L² projection, which leads to a very computationally efficient block-diagonal system of equations. In the open literature, the recovered stresses are usually computed from the minimization of an error functional and by consequence these stresses, in general, are more accurate than the raw stresses. Such feature is often explored to build error estimators, however in this work a novel application for the recovered stresses is presented, once now they are implemented aiming to improve the accuracy of a SIF extraction method. The CIM was chosen as extraction method due to the following features: it presents a high accuracy comparable to J integral and its numerical implementation is less complex than the cutoff function method (CFM). Finally, numerical examples are presented to demonstrate the benefits associated to application of the recovered stresses using both GFEM and SGFEM methodologies. These examples address different opening modes as well as horizontal and inclined cracks. Aspects as accuracy and path independent property are discussed.
Keywords
Generalized/Stable Finite Element Method, Stress intensity factors, Recovered stresses, Contour integral method
