Abstract
One of the two spindles in the X-lift fractured suddenly during normal operation. The fracture occurred at the notch where the bending moment might be the maximum. Macrofractographic features associated with rotating-bending fatigue are evident on the fracture surface. The 3-D finite element analysis of the X-lift reveals that the spindle rotated under bending. The measured surface strain of the spindle varies cyclically as the spindle rotates. It supports that the spindle rotated under bending. The X-lift is not perfectly symmetrical with respect to both the horizontal and the vertical plane. The slightly unsymmetrical deformation can cause the bending of the spindle.