ANALYSIS OF FATIGUE-CRACK GROWTH IN ROTARY BEND SPECIMENS AND RAILWAYAXLES

Fatigue crack growth tests have been carried out on pre-cracked specim ens of steel AFNOR XC 38 under rotary bending conditions. The semi-ell iptical surface crack shape evolution was determined and the results w ere analyzed by da/dN =f(Delta K) using a stress intensity factor solu tion for semi-elliptical surface cracks in round bars subjected to a b ending stress modified to take into account the rotatary bending condi tions. Results show a very good correlation with fatigue crack growth data obtained in standard centre cracked tension specimens of the same steel. An application to the sensitivity of design parameters to an a nalysis of cracked railway axles is proposed, allowing an improvement in maintenance procedures.