Influence of the mean loading on fatigue crack growth rate and life under bending

The paper contains the results of experimental tests of the fatigue crack growth rate of steels 10HNAP and 18G2A under bending for different load ratios. In the tests, plane specimens with external unilateral sharp notches as stress concentrators were used. The results of the experimental tests are described by a nonlinear formula based on the $ {\Delta}J$-integral range. The proposed formula for description of the fatigue crack growth rate, including the $ {\Delta}J$-integral range, satisfactorily describes the results obtained experimentally.