A freight-car axle AB is loaded approximately as shown in the figure, with the forces P representing the car loads (transmitted to the axle through the axle boxes) and the forces R representing the rail loads (transmitted to the axle through the wheels). The diameter of the axle is d= 82 mm, the distance between centers of the rails is L, and the distance between the forces P and R is b = 220 mm.
Calculate the maximum bending stress σmax in the axle if P = 50 kN.
