Assessment of Aircraft Structural Service Life Using Generalized Correction Methodology

You are here: Homepage > Search

Assessment of Aircraft Structural Service Life Using Generalized Correction Methodology

Dui, Hongna / Liu, Xiaodong / Dong, Jiang / Zhang, Lixin

Abstract At present, there is no common model or approach that can comprehensively cover all stages and influence factors of the general fatigue and crack growth behavior. Classical fatigue models cannot be directly applied to service life prediction under variable amplitude (VA) load spectra without calibration and validation by fatigue tests data. In this research, a generalized correction methodology is proposed, which is divided into life correction rule and crack growth rate (CGR) correction rule, the former is limited to crack initiation models, and the latter is limited to effective block approach (EBA) model, based on the assumption that the uncalibrated classical fatigue models can provide a reasonable prediction for the relative severity of two VA load spectra. The application procedure of generalized correction methodology is detailed, and the way how to select the durability and damage tolerance (DADT) optimal models is provided. Furthermore, sensitivity analyses of model parameters largely affecting the accuracy of life predictions in crack initiation models and EBA models are presented and suggestions on their derivation are given. Finally, case study of some bulkhead representative coupon data under three test spectra at different stress levels is reviewed where the implementation of generalized correction methodology has been comprehensively examined and validated, which is anticipated to provide highly accurate and reliable structural service life assessment for agile fighter aircraft under operational load spectrum.