PSI - Issue 18

2

Author name / Structural Integrity Procedia 00 (2019) 000–000

Mikhail Sokovikov et al. / Procedia Structural Integrity 18 (2019) 262–267

263

Peer-review under responsibility of the Gruppo Italiano Frattura (IGF) ExCo.

Keywords: plastic strain localization, microdefects, dynamic loading, numerical modeling, study of the surface relief of the deformed samples

Intrudiction The localization of plastic strain in metals under dynamic deformation can be due to the influence of various factors, such as temperature, velocity, the magnitude of deformation, and the evolution of the material structure, Giovanola J. H. (1988), Marchand А., Duffy J.(1988), Rittel D.at al.(2008). Today, there are two most commonly accepted viewpoints about the mechanisms of strain localization: thermoplastic instability and mechanisms associated with the evolution of the structure. Experimental studies of the microstructure of localized-shear bands carried out in a number of studies show that one of the mechanisms for the formation of plastic shear bands is multiple instabilities in the meso-level defect system. The constitutive relationships linking the strength and relaxation properties of materials with the evolution of a defective subsystem and our notion of the role of collective defect modes in the mechanisms of structural relaxation and deformation localization were used to numerically simulate a localized plastic shear in relation to the data of original experiments and structural studies, Naimark O.B . (2004).

Fig.1. Infrared image of the speciment made of alloy AMg6 and the plot of temperature as a function of coordinate at the specified instant of time. The maximum temperature along the perimeter of the hole is ~ 43 0 C.