Fracture Analysis of a Spindle in the X-Lift

One of the two spindles in the X-lift broke suddenly during normal operation. The location of the breakage is where considerable stress concentration occurs and moreover the bending moment is at the maximum. Macrofractographic features associated with rotating-bending fatigue are evident on the fracture surface. The measured surface strain of the spindle varies cyclically as the spindle rotates and supports the rotating-bending fatigue. The X-lift is not perfectly symmetrical with respect to the horizontal plane. The unsymmetrical deformation can occur and cause the bending of the spindle. The 3-D finite element analysis of the X-lift revealed the bending of the spindle.