Numerical Comparison of Glider Load Spectra

Abstract

Eight glider load spectra which were developed in Germany, Australia and Poland were investigated numerically. The original data commonly used for the presentation of a cumulative frequency distribution were ordered in the scheme of a 29x29-Markov transition-matrix. For the individual lifetime assessments, fatigue data of glass and carbon fibre composites representing the girders and shear webs of wings have been considered. The damage accumulation was performed according to the linear Palmgren-Miner rule. The lifetime was calculated for different maximum design values of the composite materials used. It became obvious that, at equal design levels of the materials, the lifetimes can differ between 2 to 5 orders of magnitude in relation to the load spectrum and the material. It was also shown that the KoSMOS-spectrum is among those yielding the most conservative results and, thus, rightly the recognized OSTIV-standard.