ABSTRACT
The estimation of fatigue crack initiation of industrial parts presents growing economic interest. In this chapter, the authors present a simple viscoelastic model in large strain in order to obtain the local dissipation (in the dumbbell specimen) which will be used as a mechanical parameter to represent the fatigue life. It shows the fatigue properties of Chloroprene Rubber (CR) in terms of alternating strain. The stress state and the energy dissipated in a laboratory specimen (dumbbell) are quite different from those existing in industrial parts which are subject to a complex stress state. To address this issue, the authors develop a local approach. This approach considers that the material has an intrinsic life determined by the history of the stress-strain which is convenient for the engineers. The fatigue crack nucleation life may be defined as the number of cycles necessary to cause the appearance of a crack of a certain size.
