A probabilistic approach to fatigue risk assessment in aerospace components

Abstract

This paper describes a new possible approach to fatigue design of aerospace components founded on probabilistic bases compared with safe life and damage tolerance that are founded on deterministic bases. A numerical tool have been introduced and explained together with the experimental activity for its validation analyses. For a typical aerospace component, such as a lap joint panel, an acceptable maximum risk level has been established and the maintenance program has been planned to ensure operating life without catastrophic failures. The analysis has shown that this new approach introduces several benefits in fatigue design.

A Probabilistic Approach to Fatigue Design of Aerospace Components by Using the Risk Assessment Evaluation

“…15 holes x 2 sides = 30 positions for each panel). In Figure 13 ( Cavallini & R. Lazzeri, 2007) the comparison is shown between the predicted crack dimensions and the corresponding experimental results at 80,000 cycles. www.intechopen.com…”

“…7, in aluminum alloy 2024-T3 (Cavallini & R. Lazzeri, 2007). They were fatigue tested under a constant amplitude load spectrum with S max =120 MPa and R=0.1.…”

“…The PISA code (Cavallini et al, 1997;Cavallini & R. Lazzeri, 2007), developed at the Department of Aerospace Engineering of the University of Pisa, allows the simulation of the whole fatigue life of typical aerospace components, such as simple plane panels, riveted lapjoint panels, Fig. 2, or stiffened panels, subjected to constant amplitude fatigue loading.…”

“…For this reason, we decided to use the PISA code itself and the simplified model of a specimen with a through crack at a lap-joint, taking into account the effects of countersink of the hole, membrane stress, by-pass loading and pin load, Fig. 8, (Cavallini & R. Lazzeri, 2007).…”

“…This paper intends to show a computer code -PISA, Probabilistic Investigation for Safe Aircrafts -and how it can be applied to the fatigue design of typical aerospace components, such as riveted joints, making it possible to integrate damage tolerance and the evaluation of the real risk level connected to the chosen inspection plan, (Cavallini et al, 1997;Cavallini & R. Lazzeri, 2007).…”