The essential parameters for structure integrity assessment in Linear Elastic Fracture Mechanics (LEFM) are Stress Intensity Factors (SIFs). The estimation of SIFs can be done by analytical or numerical techniques. The analytical estimation of SIFs is limited to simple structures with non-complicated boundaries, loads and supports. An effective numerical technique for analyzing problems with singular fields, such as fracture mechanics problems, is the extended finite element method (XFEM). In the paper, XFEM is applied to compute an actual stress field in a two-dimensional cracked body. The XFEM is based on the idea of enriching the approximation in the vicinity of the discontinuity. As a result, the numerical model consists of three types of elements: non-enriched elements, fully enriched elements (the domain of whom is cut by a discontinuity), and partially enriched elements (the so-called blending elements). In a blending element, some but not all of the nodes are enriched, which adds to the approximation parasitic term. The error caused by the parasitic terms is partly responsible for the degradation of the convergence rate. It also limits the accuracy of the method. Eliminating blending elements from approximation space and replacing them with standard elements, together with applying shifted-basis enrichment, makes it possible to avoid the problem. The numerical examples show improvements in results when compared with the standard XFEM approach.

JO - Archive of Mechanical Engineering L1 - http://www.czasopisma.pan.pl/Content/84548/PDF/07_paper.pdf L2 - http://www.czasopisma.pan.pl/Content/84548 IS - No 4 EP - 483 KW - stress intensity factor KW - extended finite element method KW - XFEM KW - shifted basis approximation ER - A1 - Stąpór, Paweł PB - Polish Academy of Sciences, Committee on Machine Building VL - vol. 58 JF - Archive of Mechanical Engineering SP - 467 T1 - Application of XFEM with shifted-basis approximation to computation of stress intensity factors UR - http://www.czasopisma.pan.pl/dlibra/docmetadata?id=84548 DOI - 10.2478/v10180-011-0028-0