Effect of the cyclic loading form on the development of brittle fracture process

The durability for a trapezoidal axial loading cycle can be carried out using a model of scale-structural fatigue for a sinusoidal shape. For materials with frequency-dependent fatigue properties the evaluation of the rectangular cycle (except the instantaneous impulses) by the sinusoidal cycle goes into a safety margin. At the zero load absence of a rectangular cycle, the maximum stress, on average, 5% lower (durability 2.5 times less) at the same number of cycles than for a sinusoidal cycle and the loading period. The results are confirmed by experimental data on high- and very high fatigue of metals and alloys.