Modélisation méso-macro de la localisation de la déformation : étude de la sensibilité au cisaillement adiabatique d'un acier à blindage

Abstract : Since the last ten years, the study of adiabatic shear bands (ASB) has ben oriented on the analysis of local phenomena which govern the localization of deformation. The importance of the microstructure (cells of dislocations or dislocations walls) was pointed out and a new subject of interest is to understand the specific characteristic mechanisms of adiabatic shear initiation. We developed a simplified meso-macro mathematical model based on the plastic inclusion with moving boundaries (Sabr & Berveiller, 1990) to try to describe the early stage microstructure evolution in this very narrow sheared surface and the strain localization. We made the hypothesis that the inclusion could be modeled by cells of dislocations or groups of dislocations cells at a meso-level. We used a progressive punching test with split Hopkinson bars which allowed us put a piston pressure on a cylindrical round shape sample of an armour martensitic steel, in a range of increasing strain rates. The complex and extremely refined microstructure required to observe this band in transmission electronic microscopy on several zones in the depth of the sharp band to understand the inside state evolution. The interesting point is to observe different stages of adiabatic sheared zones and very high sheared zones the strain gradient within the same sample is important to identify the initialization conditions of adiabatic shear band. We also developed a model to study the behaviour of materials when localization of deformation appears. The interest is to propose a technical methodology for others materials and their improvement in industrial applications cases
Document type :
Theses
Complete list of metadatas

Cited literature [107 references]  Display  Hide  Download

https://hal.univ-lorraine.fr/tel-01775902
Contributor : Administrateur Du Ccsd <>
Submitted on : Tuesday, April 24, 2018 - 3:46:44 PM
Last modification on : Thursday, June 21, 2018 - 1:21:32 AM
Long-term archiving on : Wednesday, September 19, 2018 - 12:25:10 PM

File

David.Frederic.SMZ9713.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01775902, version 1

Collections

Citation

Frédéric David. Modélisation méso-macro de la localisation de la déformation : étude de la sensibilité au cisaillement adiabatique d'un acier à blindage. Autre. Université Paul Verlaine - Metz, 1997. Français. ⟨NNT : 1997METZ013S⟩. ⟨tel-01775902⟩

Share

Metrics

Record views

10

Files downloads

17