Résumé
In this work we present an analysis of the formation of multiple adiabatic shear bands in stainless steel 304L. Using both analytical criteria and numerical calculations, we analyze instability and shear band spacing in simple shear problems such as under torsional loading of a thin walled-tube. The Zerilli- Armstrong model which successfully describes the deformation response of metals at high strain rates is used. The perturbation approach associated with numerical methods is used to determine the instability modes and their corresponding spacing. The shear band spacing is computed using Molinari's postulate which suggests that the wavelength of the dominant instability mode with the maximum growth rate at a given time determines the minimum spacing between shear bands. The effect of grain size on shear band spacing is discussed. We show that the variation of the Taylor-Quinney parameter as a function of shear strain_(_), is an important parameter that plays a significant role in the calculation of the shear band spacing.