AN IMPROVED TECHNIQUE FOR THE PREDICTION OF AXIAL FATIGUE LIFE FROM TENSILE DATA

This paper introduces an improved technique over existing methods for the prediction of axial fatigue life from uniaxial tensile data. The m ethod uses multilinear regression analysis for initial prediction of t he elastic and plastic strain amplitudes at 10(6) and 10(4) reversals to failure respectively from uniaxial tensile data. The fatigue streng th coefficient is assumed to be equal to the true fracture stress of t he material. The fatigue ductility coefficient is approximated to be e qual to the logarithmic ductility of the material. The fatigue strengt h exponent and fatigue ductility exponent are then located on the stra in-life curve by making use of the estimated elastic/plastic strain am plitudes, logarithmic ductility and the true fracture stress of the ma terial. The validity of the method was investigated by examining 49 st eels whose material properties cover a wide range of variables that mi ght affect fatigue behaviour.