Browsing by Author "KHELIL Foudil"

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    Analyse numérique de la propagation de la fissure par le critère T-stress
    (2016-09-16) KHELIL Foudil; Encadreur: BELHOUARI Mohamed
    Résumé (Français et/ou Anglais) : Analysis of breakdown of the behavior of cracked structures is dominated mainly by the stress field near the crack tip. The interest in mechanics of linear elastic fracture mainly focuses on the stress intensity factors that describe the singular stress field at the crack tip and govern the breakdown of a test when his stress intensity factor criticism is reached. The usefulness of the crack tip parameters representing the singular stress field was shown early on by many research. However, there is experimental evidence that also the stress contributions acting on a long distance from the crack tip can affect the fracture mechanics properties. The stress contribution term (first term higher order expansion of Williams field, appointed by the T-term stress) is the next important parameter. Sufficient information on the stress state is available, if the FIC and the T-stress are known. In special cases it may be advantageous to also know the higher coefficients of expansion of the series of constraints. This is a method that allows to know the stress intensity factors and T-stress for cases of complicated loading was determined. These calculation methods are explained in detail. For this purpose a method, called the method of virtual strain gauge is proposed for accurate numerical evaluation of the stress intensity factor (SIF), the T-stress and biaxial parameter β. This method is based on the optimal positions of the virtual strain gauges located close to the crack tip such that the effect of dominant singular strains is canceled. The applicability of the proposed method is examined for incidence terms of quasi-static loading and low speed on a (TPB in three-point bending) and test single crack on the edge (SENT). The effects of loading conditions, configuring the geometry and length of the crack were presented and discussed. A good agreement was found between the results of the proposed method and those of numerical and experimental data published previously. Furthermore, we note that the proposed method is an alternative and more advantageous than the extrapolation method because of its simplicity and its accuracy of results.