Some Remarks on the Crack Growth Analysis in Structural Components under Service Loading

Structural components of construction machinery and open-pit machines often contain cracks or crack-like defects initiated at notches under service cycling loading. Those cracks can decide on the process of material destruction. In order to determine the time spent on the stable fatigue growth of such cracks, the crack growth analysis needs to be carried out. One of the most important issues in the crack growth analysis is acquisition of straining history and preparation of its spectrum for fatigue calculations. However, durability forecasts may substantially differ one from another, depending on the type of applied assumptions and simplifications (i.e. calculations in the loading blocks and their sequence or taking into account the mean stress). The paper presents the selected aspects of the fatigue crack growth analysis carried out with the use of the service loading acquired on the real open-pit machine - KWK 910 excavator.