Issue 38

M. Kepka et alii, Frattura ed Integrità Strutturale, 38 (2016) 82-91; DOI: 10.3221/IGF-ESIS.38.11 89 probability. For this purpose, a median S - N curve must be obtained first – by shifting the curve defined in the standards for 97.5 % failure probability. The S - N curve equation is as follows i a i N C m d s N 1 , log log log (log )       (6) The actual probabilistic assessment of fatigue strength is carried out using an MS Excel sheet. First, the distributions of individual components of the load capacity factor for corresponding tolerance limits of S - N curves are found. Then, the distribution of the combined load capacity factor is calculated. The real distributions are approximated by lognormal distributions Figure 8 : Determination of the moving window for the probabilistic characterization of the vehicle run. O BTAINED RESULTS DISCUSSION he above procedure was applied to the measured location of the articulated joint (Fig. 5). Distributions of individual components of the load capacity factor were determined. Fig. 9 shows example plots of their distribution functions using the median S - N curve. In this case, the random nature has been accounted for on the part of the load only. Figure 9 : Probability distribution of particular loading factor components a x , a y and a τxy . T