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This paper presents a new approach to predict the high cycle fatigue limit of defective material submitted to multiaxial loading. Defects are simplified to a half spherical void at the surface of a specimen. Finite Element (FE) method is used to determine stress distribution around defect for different sizes and loading levels. Papadopoulos high cycle fatigue criterion is used to calculate equivalent stress around defect. Based on stress analysis, a definition of affected area is proposed, in which the Papadopoulos criterion is violated. The evolution of the affected area, versus the amplitude of loading and defect size leads to determine fatigue limit for defective material. Results are in good agreement with experimental investigations and show that the affected area is a good parameter to predict the influence of a defect on multiaxial fatigue behaviour.

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The aim of this study is to determine the vaporization rate of an under-ventilated pool fire in a closed environment. A theoretical model that allows the burning rate of fuels to be determined for compartment fires under vitiated conditions is presented. The radiative and convective components of the heat flux from the flame to the pool surface are both evaluated and related to the ambient oxygen mass fraction. The model was first compared with the empirical correlation determined by Peatross and Beyler [1] before being applied to pool fires using heptane and PMMA as fuels in a small-scale apparatus. The global model presented here was then implemented in the CFD code ISIS and was validated against experiments involving a hydrogenated tetra-propylene pool fire test in a confined and mechanically ventilated compartment. It is shown that the model is able to correctly predict the fuel mass loss rate and provides a reasonable assessment of the heat flux from the flame to the pool surface.KEYWORDS: CFD, compartment fires, modeling, heat transfer, heat release rate. NOMENCLATURE LISTING

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