文档介绍：International Journal of Fatigue 23 (2001) 587–598
ate/ijfatigue
On the fatigue reliability evaluation of ponents under
service loading
R. Tovo *
Department of Engineering, University of Ferrara, via Saragat 1, I-44100 Ferrara, Italy
Received 6 October 2000; received in revised form 27 February 2001; accepted 28 February 2001
Abstract
The fatigue strength evaluation of ponents under service loading is affected by several uncertainties. Proper statisti-
cal tools should be used to manage the large amount of causalities and the lack of knowledge on the actual strength-affecting
parameters. This paper deals mainly with the statistical analysis to be performed on experimental load histories in order to evaluate
fatigue loading spectra and the problems in extrapolating from measured load history to the ponent life. Then, a method-
ology for assessing the reliability of structural details under random fatigue loading is analysed. This bines (under
a linear cumulative rule assumption) the loading spectra, obtained by the new approach, and the constant-amplitude fatigue strength
modelled by means of a conventional log-normal distribution. By so doing it is possible to distinguish many causes of uncertainty
and suggest evaluations with proper confidence limits. The theoretical aspects developed are applied to mountain bike stems and
they show the presence of a large uncertainty margin in reliability evaluation under service loading when there are no considerable
quantities of experimental data available (both in load histories ponent fatigue strength). 2001 Elsevier Science Ltd. All
rights reserved.
Keywords: Fatigue reliability; Fatigue damage; Loading spectra
1. Introduction Even if his analysis is sufficiently accurate, it is neces-
sary to note that there is a fundamental difference among
The fatigue behaviour of ponents the causes described. The first three items are actual ran-
under service loading and its evaluation are usually dom varia