Damage tolerance analysis of structural components under general load spectrum

Abstract

In this investigation fatigue behaviour of damaged structural components under cyclic loads constant amplitude and load spectrum is considered. Primary attention of this investigation is the establishment of computation procedure for the evaluation of the residual life of aircraft attachment lug type structural elements in the presence of initial cracks. In this investigation for residual life estimation and crack growth analysis Strain Energy Density ( SED) method is used. The SED method uses the low-cycle fatigue (LCF) properties of the material in crack growth analysis. In this approach experimentally obtained dynamic properties of the material such as Forman's constants are not required when this method is concerned. The complete computation procedure for the crack propagation analysis using low-cycle fatigue material properties is illustrated with the damaged structural elements. To determine analytic expressions for stress intensity factors (SIF) singular finite elements are used. Results of numerical simulation for crack propagation based on strain density method have been compared with own experimental results.