ON A POSSIBLE MECHANICAL QUANTIFICATION OF FATIGUE DAMAGE

Criteria exist in the field of multiaxial fatigue for predicting the c yclic lifetime for a high number of cycles. They can predict the fract ure of a part, but they are not able to calculate the damage level int roduced. Since such theories are often used in Research and Developmen t departments, we have based this present study on these criteria. Exp eriments were made on more than 1000 specimens that now allow us to pr opose a general procedure for the use of multiaxial criteria after pre -cycling, i.e. for non-virgin materials. We also suggest the introduct ion of a threshold, which depends on the damage level, to filter out s mall cycles.