The paper focused on the service loads and cumulative damage analysis. The description of the service load contains: the examples of statistical analysis of random stress process, stress spectrum and stress program.This work presents a method of determining of structural parts random loading distribution,  \ .
The methods described in this paper are the ways to reach the solution goals by means of a characteristic curve of strength reliability with the maximum use of computer technology.
The results of its application would be presented to mobile facility elements.
A motorcycle running along a road is subjected to two vertically imposed displacements, one at each wheel. The description of the road surface must be complete enough to describe adequately the displacement imposed at each wheel at least in statistical terms and the correlation between the two displacements.In some mobile machinery and equipment, or their elements, the problem of fatigue. The problem of fatigue strength and service-life,  \ , as the most important phenomena of strength reliability under those conditions, is connected more or less with a certain degree of uncertainty.The basic elements of the fatigue life evaluation, \ , are reviewed in Fig
 Kopecky, M.: Non-destructive techniques for measuring random loading signals and their analysis.
VDI-Berichte,Nr. 940: 33-39,Dusseldorf,Germany, 1992.
 Kopecky, M.,Vavro,J.: A fatigue curve as a random element. In: Proceeding of 5th Polish - Slovak Scientific Conference on "Computer Simulation in Machine Design.Wierzba, Poland, pages 79-82, ISBN 83-912190-3-8, 2000.
Szala, J.: Fatigue fracture of parts of structures as a vibration effect . In: Proceeding of 16th Symposium on “Vibration in physical system”,Poznan-Blazejewko, Poland, pages 40-49, 1996.
Saobraćajna sredstva i transport