The Influence of Slant Cracks on Rotor´s Torsional Shear Stress

In order to study the influence of slant cracks on rotor´s torsional shear stress, the mode III stress intensity factors in different positions of slant crack rotor, with dip angles (the angle between crack surface and axial line) greater than 60 degrees and at different depth ratios of shafting, are analyzed and calculated .The results show that: the stress intensity factor of the same position and dip angle grows with the increase of depth ratio, in the case of the same depth ratio and dip angle, the stress intensity factor decreases with the growth of the distance to the crack center, and the greater the dip angle is, the faster it declines nearby the crack edge. The corresponding curves of stress intensity factor under different depth ratio and dip angle are drawn out, and a critical relative difference concerning the torsional shear stress between slant cracks and transverse cracks is defined. Furthermore, the critical dip angle with regard to different engineering allowable errors is confirmed, which would be used to decide when the transverse crack could be used to substitute the slant crack model in engineering applications.