Statistical modelling of the influence of the stress ratio on the
fatigue strength estimation. Application on specimens coming from
riveted structures.
- Paul Dario Toasa Caiza,
- Stephane Sire,
- Bernard Espion,
- Muriel Ragueneau
Abstract
As testimony of the engineering development during the industrial
revolution, old riveted bridges are maintained by several policies
worldwide and in some cases because of their historical importance
protected. A main concern of these policies is preserving their
structural integrity, which depends on a fatigue assessment of their
components and assemblies. In these structures, the stress ratio
considerably affects the fatigue strength, but the actual standards do
not consider this fact. Some deterministic models have been proposed in
order to overcome this issue. However, they are based on restrictive and
empirical assumptions. Moreover, no statistical considerations are made,
although fatigue strength is a random variable. In this paper, the
suggested models are studied and then enhanced by statistical
considerations. Finally, a statistical fatigue strength model as
function of the stress ratio is proposed and applied on riveted
specimens from old German Bridges and newly manufactured specimens of
steel S235.