Strain Localization, Strong Discontinuities and Material Failure: A Strain Injection Procedure (trabajo presentado como Plenary Lecture por J. Oliver)

OLIVER J; A.E HUESPE; DIAS I.

Barcelona

Congreso; Computational Plasticity XI Fundamentals and Applications; 2011

Cimne

The work explores the links of classical strain localization methods and strong discontinuityapproaches for the purposes of modelling material failure in quasi-brittle materials. A combination ofstrain localization techniques and strong discontinuity kinematics is used to remove the typical flaws(stress-locking and mesh bias dependence) of the classical strain localization methods, and reduce thesophistication of the strong-discontinuity based methods (avoiding tracking algorithms). The conceptof strong discontinuity is initially substituted by that of weak discontinuity capturing thedisplacement jump through its distribution (smearing) in a finite length: the oriented with of a finiteelement through which the fracture passes in a rather diffuse manner. In other words, the classicalstrain localization concept is brought to the approach, no strong discontinuity enrichment is made andstandard constitutive models are used in a classical strain localization setting. However, in order toremove the spurious mesh orientation dependence, constant strain localization modes are injected, viamixed finite elements formulations, to the path of elements that are going to capture the cracks.Moreover, in a second stage, and in order to minimize stress locking, the elemental kinematics isenhanced by the injection of an elemental strong discontinuity mode, to those elements that belong tothe localization band. These modes, as well as their injection time, are characterized from theinformation provided by the SDA. Then, the obtained approach enjoys the benefits of the strongdiscontinuities one, at a complexity similar to the classical, and simpler, localization methods.Representative numerical applications illustrate the performance of the method