This paper introduces means for fatigue damage rates estimation using Laplace distributed multiaxial loads. The model is suitable for description of stresses containing transients of random amplitudes and locations. Explicit formulas for computing the expected value of rainflow damage index as a function of excess kurtosis are given for correlated loads. A Laplace model is used to describe variability of forces and bending moments measured at some location on a cultivator frame. An example of actual cultivator data is used to illustrate the model and demonstrate the accuracy of damage index prediction.
The authors are thankful to Väderstad-Verken AB for supplying the cultivator data. The second author acknowledges Riksbankens Jubileumsfond Grant Dnr: P13-1024 and Swedish Research Council Grant Dnr: 2013-5180, while the third author acknowledges Knut and Alice Wallenberg stiftelse for their support.