A novel isotropic quasi-brittle damage model applied to LCF analyses of Al2024

Abstract

The current paper deals with the assessment and the numerical simulation of low cycle fatigue of an aluminum 2024 alloy. According to experimental observations, the material response of Al2024 is highly direction-dependent showing a material behavior between ductile and brittle. In particular, in its corresponding (small transversal) S-direction, the material behavior can be characterized as quasi-brittle. For the modeling of such a mechanical response, a novel, fully coupled isotropic ductile-brittle continuum damage mechanics model is proposed. Since the resulting model shows a large number of material parameters, an efficient, hybrid parameter identification strategy is discussed. Within this strategy, as many parameters as possible have been determined a priori by exploiting analogies to established theories (like P' law), while the remaining free unknowns are computed by solving an optimization problem. Comparisons between the experimentally observed and the numerically simulated lifetimes reveal the prediction capability of the proposed model.

Residual Strength Improvement of an Aluminium Alloy Cracked Panel

“…In Figs. (4)(5)(6) the comparisons between numerical and experimental results have been shown; as expected, the numerical results obtained are in good agreement with the experimental ones as proof of the relevance of the model adopted. Fig.…”

“…When such cavities begin to grow in size, they cause local severe stress-strain fields in the surroundings of small inclusions, thereby nucleating small-scale cavities which participate to the final phase of the coalescence process and therefore to the macroscopic crack growth. The process of cavity growth is well understood and the relative models are quite advanced [3,4], while the mechanism of nucleation and coalescence, as well as the associated micromechanics, are less understood even if some papers provide a good description of such mechanisms [5,6]. It is clear that improving the understanding of the above mechanisms and of their effects on failure modes and fracture resistance will result in a better ease to develop micromechanical prediction tools for the analysis of real components which behave in the nonlinear fracture mechanics field 1 .…”

Constitutive Modelling of Damage Evolution and Martensitic Transformation in 316L Stainless Steel

“…Thus, in the future work two separate scalar or tensorial type damage variable should be used (e.g. Kintzel et. al., 2010;Egner et.…”

Inelastic Behavior of Materials and Structures Under Monotonic and Cyclic Loading

“…More advanced models of damage in rock-like materials, where damage rate is derived from the generalized normality rule applied to the damage potential were derived for example by ; Voyiadjis et al (2008); Kintzel et al (2010); Murakami (2012); Skrzypek and Kuna-Ciskal (2003).…”