Shear Localization: A Historical Overview

Abstract

This review presents a historical approach to the development of understanding of the shear localization phenomenon in materials, concentrating particularly on impact. Deformation localization under these conditions is widely referred to as adiabatic shear banding as the timescales are such that the distances heat can diffuse are small. Dimensional analysis shows that the phenomenon is ultimately intractable to linear algebraic analysis, as it is a coupled mechanical/thermal problem. However, various linear analyses from the literature are discussed along with their limitations as they shed light on the influence of various material properties. The aim of gaining understanding is to be able to engineer materials with the required localization (and hence fracture) characteristics. The most advanced analyses show that shear band widths and spacings are determined by optimizing the diffusion of heat and inertia. Because inertia is involved, the phenomenon cannot be understood simply as a materials property: geometry and structure must play a role.

Shear Localization in Dynamic Deformation: Microstructural Evolution

“…The theories by Grady and Kipp, [86] Wright and Ockendon, [88] and Molinari [89] are presented in the companion paper in these proceedings by Walley. [224] The three equations are given in Table III. We describe briefly below the evolution of multiple adiabatic shear bands in commercially pure titanium and Ti-6Al-4V alloy through the radial collapse technique of a thick-walled cylinder under highstrain-rate deformation (experimental configuration [219] with results by Xue et al [39] shown in Figure 1(c).…”

Suppression of repeated adiabatic shear banding by dynamic large strain extrusion machining

“…(4) is the same as the momentum equation of Burns and Davies (2002). Compared with the momentum equation in simple shear (Dodd and Bai, 2012;Meyers, 1994;Walley, 2007;Wright, 2002), the effect of the compressive stresses from the tool and the constraint as well as material convection due to chips flow are added in Eq. (4) during DLSEM.…”

Microstructural Changes of the Nanostructured Bainitic Steel Induced by Quasi-Static and Dynamic Deformation

“…Transformed bands in steels may be as narrow as 5-10 μm and will appear white after nital etching. Deformed bands in steels are generally broad and do not etch white [10,11].…”