A 2500 mm long rotating shaft with a solid circular cross-section is supported at its ends by bearings that can be modeled as simple supports. The middle of the shaft has a notch with a 1.25 mm radius.
It carries a stationary transverse force of F-800 N at section B, a constant axial force of FA-6000 N, along with an axial torque that fluctuates between -40 and 180 N-m.
(a) The complete set of internal load diagrams for this shaft are as follows:i. Normal force diagramii. Shear force diagramiii. Bending moment diagramiv. Torque diagramb. The static factor of safety using the MSSTF at section C can be given by,The static factor of safety using the DETF at section C can be given by,c. The fatigue factor of safety using the Soderberg criterion can be given by,d.
The fatigue factor of safety using the Goodman criterion can be given by,The shaft is made of carbon steel with a yield strength of 350 MPa and a tensile strength of 830 MPa (120 ksi). It has a machined surface finish.
The maximum shear stress theory factor (MSSTF) is given by,DET (Distortion Energy Theory) or Von Mises theory factor is given by,The Soderberg criterion is given by,The Goodman criterion is given by,where,SM = Allowable Static StressSF = Static Factor of SafetyS-N Diagram or Wohler Curve allows for the determination of fatigue strength by plotting the fatigue life against the alternating stress or strain amplitude. Assume no elevated temperatures and a reliability of 50% (CT=Ce=1.0).