文档介绍：ADVANCES IN FATIGUE AND FRACTURE MECHANICS ANALYSES
FOR AIRCRAFT STRUCTURES
J. C. Newman, Jr.∗
This paper reviews some of the advances that have been made in stress
analyses of cracked ponents, in the understanding of the
fatigue and fatigue-crack growth process, and in the prediction of
residual strength plex aircraft structures with widespread
fatigue damage. Finite-element analyses of cracked structures are now
used to determine accurate stress-intensity factors for cracks at
structural details. Observations of small-crack behavior at open and
rivet-loaded holes and the development of small-crack theory has lead
to the prediction of stress-life behavior ponents with stress
concentrations under aircraft spectrum loading. Fatigue-crack growth
under simulated aircraft spectra can now be predicted with the crack-
closure concept. Residual strength of cracked panels with severe out-
of-plane deformations (buckling) in the presence of stiffeners and
multiple-site damage can be predicted with advanced elastic-plastic
finite-element analyses and the critical crack-tip-opening angle
(CTOA) fracture criterion. These advances are helping to assure
continued safety of aircraft structures.
INTRODUCTION
In 1969, Schijve in the Second Frederik J. Plantema Memorial Lecture [1] stated that “fatigue in
aircraft structures is a problem for which quantitative and generally accepted solutions are not
available.” During the past 30 years, many advances have been made in the stress analyses of
cracked ponents, in understanding the fatigue and fatigue-crack growth behavior in
metallic materials, and in the prediction of residual strength plex built-up aircraft structures
with widespread fatigue damage. Although the failure rate in aircraft structures due to fatigue
and structural failure has dropped significantly [2] from the mid-1950’s, the fatigue and fracture
community must stay alert. The munity should continue to improve the
understa