@article{eprints2304, publisher = {Springer}, journal = {Meccanica}, author = {Alberto Carpinteri and Marco Paggi}, title = {The effect of crack size and specimen size on the relation between the Paris and W{\"o}hler curves}, year = {2014}, volume = {49}, month = {April}, pages = {765--773}, number = {4}, url = {http://eprints.imtlucca.it/2304/}, abstract = {Paris and W{\"o}hler?s fatigue curves are intimately connected by the physics of the process of fatigue crack growth. However, their connections are not obvious due to the appearance of anomalous specimen-size and crack-size effects. In this study, considering the equations for a notched specimen (or for a specimen where failure is the result of the propagation of a main crack) and the assumption of incomplete self-similarity on the specimen size, the relations between the size-scale effects observed in the Paris and W{\"o}hler?s diagrams are explained. In the second part of the work, the behaviour of physically short cracks is addressed and, considering a fractal model for fatigue crack growth, the crack-size effects on the Paris and W{\"o}hler?s curves are discussed.} }