Damping caused by fatigue in porous 316L steel

An analysis of the effect of microcracks in porous metals on amplitude-dependent internal friction (ADIF) is carried out. A mathematical model is developed, which takes into account an initial distribution of microcracks lengths defining subsequent crack growth during cycling. Using the Dugdale model, the linear density of microplastic zones at the tips of the microcracks is obtained as a function of applied stress and porosity. Resulting simulations of internal friction are compared with corresponding experimental data.