Aircraft duraluminum wing spar fatigue testing

Abstract

Experimental fatigue crack growth analysis of the aircraft structural component subjected to different cycling loading has been presented. The purpose of the experimental test was to evaluates the fatigue behavior of the real aircraft spar, made in aluminum 2024-T3. In-house laboratory fatigue test installation is described in the paper. The spar-test specimen has been manufactured specifically for the cycling damage testing. Test results were obtained with most modern equipment for data acquisition. Applied loads and obtained spar fatigue results are described in detail. Conclusions have been made with reference to the previous work on the duraluminum spar fatigue testing. As it is presented in the previous work with advanced numerical methods for fatigue analysis, in this paper is given an opinion on the same. At the end, possible directions of the further experimental spar fatigue testing is given and shows us that it makes sense to make the comparison beetwen real and numerical results only in situations where cracks behave similarly and the numbers of required cycles are about the same.

Residual life estimation of cracked aircraft structural components

“…Some aspects of practical design with respects residual life estimations are given in references [12,13,15,16]. Finally, the number of cycles until failure can be determined by the integration of the relation for the fatigue crack growth rate:…”

Incorporating aged martensite model in residual stress prediction of ferritic steels girth weld

“…The stress intensity factor, which describes the stress distribution in the crack tip region, determines the residual strength of structures contained cracks [2]. The cracks may grow as a result of fatigue load [3]. In fatigue load, stress intensity factor threshold (K th ) is lower for the element with induced residual stress [4].…”

Measuring strain in sheet metals

“…On one side, theory is able to propose quick explanations and solutions, generally valid for a large spectrum of simplified and mildly simplified problems [5,6]. On the other side, numerical calculations, mainly performed by Finite Element Methods (FEM) [7] or meshless methods [8,9], permit to investigate situations that are not far from reality in terms of complexity of systems and/or physical occurrences [10][11][12][13][14].…”