ESDU 84017:2007

ESDU 84017 provides a graphical method for predicting failure in the contact area of two elastic bodies subjected to combined normal and tangential loading. The method assumes that the ratio of the shear stress to the normal stress is constant throughout the affected region and equal to the sliding coefficient of friction. It requires initial information that can be obtained from ESDU 78035 on the maximum compressive stress and the contact area shape. With these values, the method provides data that enable failure to be predicted in one of three situations. Firstly, for use with the von Mises criterion for ductile failure, it enables the maximum equivalent stress to be evaluated and, where the material properties vary with depth (case hardening, for example), provides its variation with depth. Secondly, it provides values of the maximum tensile stress for use in predicting failure of brittle materials. Finally, for use in predicting fatigue failure, it provides the maximum value of the range of orthogonal shear stress, and its variation with depth. Practical worked examples illustrate the use of the method. See also ESDUpac A9434 in the Mechanisms or Tribology Series for a Fortran program providing solutions to this problem.