On the Bursting of Rotating Grinding Wheel

Abstract

We could take the photographs of the bursting state of the vitrified wheels by the stroboscope and the high speed camera, thus the cause of wheel fracture has been investigated by these photographs.
The following results are obtained :
(1) In a rotating wheel, the initial crack takes place at a point on surface of the arbor hole by the circumferential tensile stress and it spreads in the direction of rotation. The wheel, then, is divided in several blocks by succeeding cracks.
(2) The initial crack is caused by the tensile stress, but succeeding cracks are caused by the bending moment as a result of centrifugal force on potential segments.
(3) As the ratio of wheel diameter versus hole diameter is larger, the number of divided block increases.
(4) The fluctuation of the critical break speed is within 23% for the wheels of the same grade and lot.