Fatigue crack initiation and growth on a steel in the very high cycle regime with sea water corrosion

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.This is an author-deposited version published in: http://sam.ensam.eu Handle ID: .http://hdl.handle.net/10985/8815 To cite this version :Thierry PALIN-LUC, Ruben PÉREZ-MORA, Claude BATHIAS, Gonzalo DOMINGUEZ, Paul C. PARIS, Jose Luis ARANA -Fatigue crack initiation and growth on a steel in the very high cycle regime with sea water corrosion -Engineering Fracture Mechanics -Vol. 77, n°11, p.1953-1962 -2010 Any correspondence concerning this service should be sent to the repository This paper is devoted to the effect of corrosion on the gigacycle fatigue strength of a martensitic-bainitic hot rolled steel used for manufacturing offshore mooring chains for petroleum platforms. Smooth specimens were tested under fully reversed tension between 10 6 and 10 10 cycles in three testing conditions and environments: (i) in air, (ii) in air after precorrosion and (iii) in air under real time artificial sea water flow. The fatigue strength at greater than 10 8 cycles is reduced by a factor more than five compared with non-corroded specimens. Fatigue cracks initiate at corrosion pits due to pre-corrosion, if any, or pits resulting from corrosion in real time during the cyclic loading. It is shown that under sea water flow, the fatigue life in the gigacycle regime is mainly governed by the corrosion process. Furthermore, the calculation of the mode I stress intensity factor at hemispherical surface defects (pits) combined with the Paris-Hertzberg-Mc Clintock crack growth rate model shows that fatigue crack initiation regime represents most of the fatigue life.

Impact Angle Effects on Erosion Maps of GFRP: Applications to Tidal Turbines

“…However, the erosion behaviour in extreme marine conditions is not well understood or established, and this includes the ability of the leading edges of tidal turbine blades to withstand the exposure conditions, where the water density is approaching three orders (784) of magnitude greater than such materials exposed to air, i.e. as in the case of composite material used for wind turbine applications [4,5].…”

The liquid metal embrittlement effect in armko-iron during high and gigacycle fatigue loading

“…The crack spreads further into the material without the influence of surfactants. Besides, on one of the specimens there were two centers of crack initiation at one site (Fig.4a), which is usually typical of fatigue failure by corrosion [11], and this is also indicated by the case when the crack is formed away from the region of maximum stresses. Thus, we can say that the effect of liquid metal embrittlement occurs only at the stage of fatigue crack initiation, and its propagation inside goes by the classical Paris law.…”

Testing methodologies for corrosion fatigue

“…In the work of T. Palin-Luc et al [11] small-scale specimens are tested for crack initiation and crack growth. The VHCF (Very High Cycle Fatigue) tests are conducted on an ultrasonic fatigue testing machine.…”