ASSESSMENT OF EXPERIMENTAL FATIGUE LIFETIME RESULTS FROM SPECIMENS WITH HOMOLOGOUS GEOMETRY BUT DIFFERENT SIZE: TWOFOLD SCALE EFFECTS IN INITIATION AND PROPAGATION

摘要

When analyzing the specimen scale effect on fatigue lifetime results two different concepts related to the initiation and propagation phases, respectively, have to be considered. The first one can be handled with the so-called Generalized Local Model as being referred to the free specimen surface and the driving force distribution acting on the specimen surface. The second one is related to the prospective crack path, here, the specimen diameter. In this work, an experimental program is performed on 41CroMo 14 using three different specimen sizes with a similar shape. The assessment using the proposed approach provides satisfactory and useful results to be applied to the practical design of components.