NASA has conducted an Airframe Structural Integrity Program to develop the methodology to predict the onset of widespread fatigue damage in lap-splice joints of fuselage structures. Several stress analysis codes have been developed or enhanced to analyze the lap-splice-joint configuration. Fatigue lives in lap-splicejoint specimens and fatigue-crack growth in a structural fatigue test article a...

This paper focuses on a theoretical approach to access the fatigue life of flexible pipes. This methodology employs functions that convert forces and moments obtained in time-domain global analyses into stresses in their tensile armors. The stresses are then processed by well-known cycle counting methods, and S-N curves are used to evaluate the fatigue damage at several points in the pipe’s cro...

BACKGROUND The aim of this study was to determine whether the fatigue responses to the same intensified rugby league competition differed depending on playing standard and physical fitness. METHODS Players from a high-standard (n = 15) and a low-standard (n = 16) junior rugby league team had lower body neuromuscular fatigue, perceptual wellbeing, and blood creatine kinase (CK) assessed over a...

In this paper, we present a dynamical systems approach to material damage identification. This methodology does not depend on knowledge of the particular damage physics of material fatigue. Instead, it provides experimental means to determine what are practically observable and observed facts of damage accumulation, thus making it possible to develop or experimentally verify appropriate damage ...

The fatigue damage calculated for an aircraft by the Individual Aircraft Tracking (IAT) programs is dependent on the quality of input data. When the input data quality is poor or invalid, aircraft operators resort to gap-filling techniques to account for missing or invalid data. Invariably, conservative estimates of fatigue damage are obtained by imposing severe penalties for invalid or missing...

A polycyclic fatigue damage model for short glass fibre reinforced thermoplastics is developed and implemented into ABAQUS FE code using UMAT subroutine. The MNL model is introduced here in terms of damage rates: ( ) ) ( 2 0 1 2 0 2 1 2 1 1 ) ( ) ( N ij ij ij ij ij ij ij ij ij ij ij e E E N d d λ β ε γ ε β β α − −       +       + = ∂ ∂ = & (1) Where N is the number of cycles. αij, β...