Experimental and theoretical analysis of a crack growth under loading with variable amplitudes

The paper presents the results of influence of the loading amplitude upon growth of the fatigue cracks in the steel. Applying the computer measure system measurements of the crack length at each phase of propagation were carried out. Investigations were carried out on specimens with the thickness of 28.5 mm. Numerical calculations were carried out according to the modified Paris formula. The results of experimental investigations and numerical research are shown in a graphic form.