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Acceptable prior fatigue damage and failure threshold for impact loading of an aluminium alloy
Author(s) -
Auzanneau T.,
Froustey C.,
Lataillade J.L.
Publication year - 2001
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1046/j.1460-2695.2001.00367.x
Subject(s) - materials science , context (archaeology) , structural engineering , catastrophic failure , aluminium , limiting , fatigue testing , toughness , fatigue limit , aluminium alloy , composite material , engineering , mechanical engineering , paleontology , biology
In a competitive economic context that aims at gains in safety, some problems of combined fatigue‐impact loadings are crucial, particularly in the case of light alloys used in the transport and aeronautical industries. One important challenge is to quantify the fatigue preloading effect on the residual dynamic plasticity of a 2017‐A T3 aluminium alloy. From an experimental modal analysis, the change in mechanical properties of prefatigued material under impact loading allows us to define the best mechanical parameter for a limiting threshold between a no‐damage state and weakened states due to fatigue predamage. For this situation a hybrid technique has been developed. A numerical model including voids (which represent surface micro‐cracks produced by the fatigue preloading) is fitted to the results obtained by the modal analysis of the damaged sample. Hence, an acceptable damage threshold (i.e. a damage critical volume below which the impact toughness is not affected by fatigue preloading) and a failure threshold are established. On the basis of this methodology, it is possible to predict the energy required for the impact failure of prefatigued specimens and therefore to predict a safe or a dangerous mechanical state.