The application of p-version finite-element methods to fracture-dominated problems encountered in engineering practice

Abstract

This paper details experience applying higher-order ( p-version) finite-element methods to highly specialized and difficult problems in structural life predictions, namely in predictions of aircraft structural fatigue life using crack growth analyses. Crack growth analyses require reliable estimates of the Mode I stress intensity factors (SIFs) for given load, boundary conditions, and geometry. Fortunately, accurate and reliable stresses and stress intensity factors, obtained quickly and efficiently from finite-element simulations performed with higher-order methods, enable basic procedures to be successfully applied to the development of advanced life prediction methods. Many FEA software packages could have been used to obtain engineering data such as SIFs and stresses. However, advanced numerical methods incorporated into higher-order finite-element methods allow the engineering analyst to have confidence in the results. This confidence comes from being able to obtain more accurate and reliable results using convenient error checking and numerical convergence of engineering data such as maximum stress and strain and SIFs, stress contours, and deformations. In addition, greatly shortened analysis schedules are realized through the use of procedures such as the automatic extraction of SIF parameters using the contour integral method (CIM). The versatility of higher-order methods is demonstrated by some examples encountered in engineering practice—multisite damage scenarios and corroded plates.