AFD has the expertise to identify primary structural elements (PSE) and perform fatigue analyses to establish life to crack initiation (strain life) for low cycle~high load spectra and life to failure using the stress life approach for medium to high cycle spectra.

AFD has extensive 'cradle to the grave' fatigue analysis experience on all major airframe and undercarriage structure. All fatigue analyses and spectra manipulation are performed using industry standard methodology and established reference data. In-house programs and MATHCAD driven hand analyses are used to optimise new designs by minimising stress concentrations and selecting materials with appropriate endurance characteristics.

For existing designs, AFD has experience of several life extension programmes including the VC10 tanker and Hawk jet trainer for the RAF and the Dassault Atlantique reconnaissance aircraft for the Italian Air Force. AFD has experience in the application of fatigue enhancement techniques which permit the lives of existing structures to be extended, thereby reducing component replacement costs.

Experience of fatigue damage analysis in the high cycle regime (>10⁷ cycles) has been gained by AFD consultants on projects such as the NHI NH90 military helicopter and the Rooivalk attack helicopter.

AFD has the necessary skills to perform Linear Elastic Fracture Mechanics (LEFM) in order to relate stress intensity to crack propagation rate. This enables crack growth lives and inspection intervals of damage tolerant structure to be evaluated. Software such as NASGRO is typically utilised for the production of the crack growth curve. Complex geometries can be analysed using MSC.MARC (FEM tool) that applies the J-integral method to determine the crack path and stress intensities.