Generating aircraft and system turbulence induced fatigue spectra for future aircraft conceptual design

Abstract

Current methods for deriving gust fatigue spectra rely heavily on empirical data collected from in-flight accelerometer recordings. These data are typically adjusted for parameters such as mass, wing area, airspeed, and air density to produce a representative spectrum. However, these techniques are constrained by their dependence on historical data and assumptions about wing dynamic behaviour across different aircraft systems. Additionally, they are restricted to analysing only the aircraft centre of gravity location. This limits their applicability to novel and future aircraft configurations, which may exhibit significantly different structural behaviours.

To overcome these limitations, this thesis proposes a novel physics-based approach for generating gust fatigue spectra during the conceptual and preliminary stages of aircraft design, with minimal reliance on historical data or assumptions about gust-related flight loads. By incorporating key fatigue response quantities and leveraging spectral representations of external disturbances, the research aims to develop, validate and implement an enhanced methodology capable of deriving gust fatigue spectra across all aircraft locations for all aircraft configurations. This innovative approach empowers designers to make informed architectural decisions early in the design process, improving both the efficiency and effectiveness of aircraft development workflows.

The thesis introduces an advanced methodology for computing gust fatigue spectra under continuous turbulence conditions, surpassing the limitations of traditional empirical frameworks. At the core of this method is a Finite Element-based technique that calculates Key Fatigue Response Quantities for discretized mission profiles and aircraft parameters. Atmospheric disturbances are modelled using well-established spectral descriptors, such as the Von Karman and Dryden models, to ensure accurate representation of environmental conditions. By integrating these components, the research derives a physics-based, lifecycle gust fatigue spectra, offering a detailed understanding of the fatigue loads experienced throughout the aircraft's operational life.

Thesis is embargoed until 31 December 2026.

Date of Award	Dec 2025
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Engineering and Physical Sciences Research Council & Rolls Royce PLC
Supervisor	Adrian Murphy (Supervisor), Marco Geron (Supervisor) & Damian Quinn (Supervisor)