The influence of variable operating conditions upon the general multi-modal Weibull distribution

For the design spectrum prediction that should be realized within the expected service life, the influence of variable loading conditions is of paramount importance. Further, the results of the measurements must be properly extrapolated and the scatter of loading spectra has to be determined to assure reliable service life prediction. To model load ranges, a general multi-modal Weibull distribution function has recently been proposed. Until now it has been verified only for fixed operating conditions. The scope of this article is to prove that the same distribution model holds for the case of variable operating conditions, too. The influence of variable operating conditions upon the distribution function is demonstrated by a few examples attained by analysing loads acting upon a structure of a fork-lift.