Verification of fatigue critical plane position according to variance and damage accumulation methods under multiaxial loading

The paper presents a comparison of fracture plane position gained from experimental tests of specimens under multiaxial loading and theoretical ones from calculation according to variance and damage accumulation methods. In the variance method it is assumed that the plane in which the maximum variance of the equivalent stress appears is critical for a material and the fatigue fracture should be expected in this plane. In the damage accumulation method the fatigue critical plane is assumed to be the plane which suffered the greatest damage during service loading. For both methods the equivalent stress is calculated according to the multiaxial fatigue failure criteria of (i) maximum normal stresses, (ii) maximum shear stresses as well as (iii) maximum normal and shear stresses in the critical plane.