Digital image correlation and infrared measurements to determine the inﬂuence of a uniaxial pre-strain on fatigue properties of a dual phase steel.
Laboratoire Brestois de Mécanique et des Systèmes (L.B.M.S.),
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The high cycle fatigue (HCF) is a major element for a great design of automotive parts. A wide part of the steel sheets for the automotive industry are stamped, sometimes deeply. During this operation, the steel is plastically strained in diﬀerent directions, so that a good prediction of the fatigue behavior requires the determination of the fatigue properties of the pre-strained material. Nowadays, the evolution of HCF properties is often neglected, because of prohibitive time dedicated to traditional fatigue campaigns. To reduce the characterization time, self-heating measurements are used. This approach permits to identify the inﬂuence of homogeneous pre-strain on fatigue properties. The aim of this paper is to develop an original experimental test to identify this inﬂuence for a wide range of pre-strain with only one specimen. The study of a particular case of specimen with a constant gradient of pre-strain is presented. Digital image correlation is a way to determine the heterogeneity of the plastic pre-strain on the specimen and infrared measurements with a ”1D” approach allows the determination of the inﬂuence of a plastic pre-strain on the fatigue properties of the studied steel.
© Owned by the authors, published by EDP Sciences, 2010