Fatigue Lifetime analysis of composites with initiation damage in bending

Introducing a soft region concept depicting the initiating damage of concrete, soft regions are distributed in matrix. Assuming concrete as two-phase composites including matrix and soft regions, considering material heterogeneity, matrix and soft regions´ number obey WEIBULL distribution in terms of element failure strength. Changing shear transfer coefficient for an open crack, soft regions volume ratio and soft regions average failure strength, Static numerical tests of four-point bending beam are carried out. On the basis, static ultimate strengths of numerical specimens and a series of stress levels used for fatigue analysis are confirmed. Every material´s fatigue life curve is assured. Keeping stress ratio 0.1, under three stress levels (1, 0.8, 0.6), fatigue numerical tests are implemented, at the same time, corresponding fatigue life distributions are achieved.