Understanding the fatigue behaviour of structural components under variable load amplitude is
an essential prerequisite for safe and reliable light-weight design. For designing and
dimensioning the expected stress (load) is compared with the capacity to withstand loads
(fatigue strength). In this process the safety necessary for each particular application must
be ensured. A prerequisite for ensuring the required fatigue strength is a reliable load
assumption. The authors describe the transformation of the stress- and load-time functions
which have been measured under operational conditions to spectra or matrices with the
application of counting methods. The aspects which must be considered for ensuring a reliable
load assumption for designing and dimensioning are discussed in detail. Furthermore the
theoretical background for estimating the fatigue life of structural components is explained
and the procedures are discussed for numerous applications in practice. One of the prime
intentions of the authors is to provide recommendations which can be implemented in practical
applications.
