Analyses of stress intensity factors for structural integrity in mechanical components

Abstract

Finite element methods offer versatile tools in structural mechanics to analyze various types of structures. The Finite Element Method (FEM) is extended to Linear Elastic Fracture Mechanics (LEFM) for the calculation of stress intensity factors, crack growth tc., with sufficient accuracy. The conventional FEM applied to LEFM is comparatively complicated since the crack tip region involves the singularities. Higher order conventional isoparametric elements are used in the analysis while near the crack tip, where the singularity occurs, enriched crack tip elements are used. Achieving significant accuracy with fewer elements is one of the main criterion in structural analysis. The method developed here has the advantage of fewer elements with minimal re-meshing and ease of modeling with less concern to aspect ratio. The p-version analysis helps in increasing the order of polynomial without the need tore-mesh and to reuse the same mesh repetitively to get the change in stress intensity factors and eventually the crack growth parameters. Stress intensity factors are a measure of stresses at the crack tip. SIF’s are calculated for various crack problems and results are compared, analyzed and presented.