Adiabatic shear band

Résumé

In physics, mechanics and engineering, an adiabatic shear band is one of the many mechanisms of failure that occur in metals and other materials that are deformed at a high rate in processes such as metal forming, machining and ballistic impact. Adiabatic shear bands are usually very narrow bands, typically 5-500 μm wide and consisting of highly sheared material. Adiabatic is a thermodynamic term meaning an absence of heat transfer – the heat produced is retained in the zone where it is created. (The opposite extreme, where all heat that is produced is conducted away, is isothermal.) Deformation It is necessary to include some basics of plastic deformation to understand the link between heat produced and the plastic work done. If we carry out a compression test on a cylindrical specimen to, say, 50% of its original height, the stress of the work material will increase usually significantly with reduction. This is called ‘work hardening’. During work hardening, the micro

Source officielle

https://en.wikipedia.org/wiki/Adiabatic_shear_band

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (2)

Chargement

Publications associées

Chargement

Personnes associées

Chargement

Unités associées

Chargement

Concepts associés

Chargement

Cours associés (1)

Cours associés

Chargement

Séances de cours associées (2)

Séances de cours associées

Chargement

Publications associées (2)

Three-dimensional adaptive meshing by subdivision and edge-collapse in finite-deformation dynamic-plasticity problems with application to adiabatic shear banding

Jean-François Molinari

This paper is concerned with the development of a general framework for adaptive mesh refinement and coarsening in three-dimensional finite-deformation dynamic-plasticity problems. Mesh adaption is driven by a posteriori global error bounds derived on the basis of a variational formulation of the incremental problem. The particular mesh-refinement strategy adopted is based on Rivara's longest-edge propagation path (LEPP) bisection algorithm. Our strategy for mesh coarsening, or unrefinement, is based on the elimination of elements by edge-collapse. The convergence characteristics of the method in the presence of strong elastic singularities are tested numerically. An application to the three-dimensional simulation of adiabatic shear bands in dynamically loaded tantalum is also presented which demonstrates the robustness and versatility of the method. Copyright (C) 2001 John Wiley Sons, Ltd.

2002

Chargement

A study of solid-particle erosion of metallic targets

Jean-François Molinari

We perform detailed finite element simulations of impact of metallic plates by spherical particles over a range of impact angles and speeds with a view to develop an insight into the fundamental mechanisms underlying solid-particle erosion. The particular experimental configuration and data set which we analyze corresponds to the experiments of Hutchings (Proc. R. Soc. London, Ser. A 348 (1976) 379), consisting of high-strength steel spherical particles striking mild-steel target plates, The material description used in calculations includes finite deformations, strain hardening, thermal softening, rate sensitivity, frictional contact, heat generation due to plastic working and friction, dynamics and heat conduction. The analysis reveals insights into the relative roles played by plastic flow, friction and adiabatic shearing over the full range of impact angles from glancing to normal impact; and over impact velocities ranging from 141 to 2000 m/s. (C) 2002 Elsevier Science Ltd. All rights reserved.

2002

Chargement