The influence of the initial microdamage anisotropy on macrodamage mode during extremely fast thermomechanical processes

Abstract

In recently proposed thermo-elasto-viscoplastic material model for metals, the damage is described by the second-order tensor, called microdamage tensor to express the experimentally observed anisotropy

Reduction of the number of material parameters by ANN approximation

“…Formally, the constitutive structure belongs to the class of simple materials with fading memory, and due to its final form and the way of incorporating the fundamental variables, belongs to the rate type materials with internal state variables [38]. The key features of the formulation (for detailed and more general formulation please see [6,35,37]) are: (i) the description is invariant with respect to any diffeomorphism (the obtained model is covariant [13]), (ii) the obtained evolution problem is well-posed, (iii) sensitivity to the rate of deformation, (iv) finite elasto-viscoplastic deformations, (v) plastic non-normality, (vi) dissipation effects (anisotropic description of damage), (vii) thermo-mechanical couplings and (viii) length scale sensitivity.…”

“…The modeling must reflect micro/nano scale of observation in order to capture physical phenomena crucial for its proper description [6,37]. As a result, the modern constitutive models include high number of material parameters.…”

Close Range Explosive Loading on Steel Column in the Framework of Anisotropic Viscoplasticity

“…Below, the fundamentals of Perzyna's type viscplasticity are presented to make the paper self-contained. For comprehensive description, the reader should follow recent papers in this field, e.g., [13,14,16,24,45].…”

“…Therefore, the filling of this gap plays a fundamental role in the presented considerations and simultaneously states the paper's most original part. Moreover, one can point out the following aspects which make the modeling in terms of the generalized thermo-elasto-viscoplastic (GTEV) unique: (i) invariance with respect to any diffeomorphism (covariant material model) [13], (ii) well-posedness of the evolution problem, (iii) sensitivity to the rate of deformation, (iv) finite elasto-viscoplastic deformations, (v) plastic non-normality, (vi) dissipation effects (anisotropic description of damage) [14], (vii) thermo-mechanical couplings, and (viii) implicit length scale sensitivity. On the other hand, it is important that the viscoplasticity theory, being a physical one, has a deep physical interpretation derived from the analysis of a single crystal and polycrystal behavior [15].…”

Non-local fractional model of rate independent plasticity

“…explicit [Borst and Pamin, 1996, Fleck and Hutchinson, 1997, Aifantis, 1999, Voyiadjis and Abu Al-Rub, 2005, Polizzotto, 2011] (e.g. via classical strain gradients) or implicit [Perzyna, 1998, Łodygowski and Perzyna, 1997, Dornowski and Perzyna, 2002, Sumelka and Łodygowski, 2011, Sumelka and Łodygowski, 2013, Voyiadjis and Faghihi, 2013, Sumelka, 2013c (i.e. via relaxation time in Perzyna's type viscoplasticity).…”