Micromechanical modeling of the interactions between the microstructure and the dissipative deformation mechanisms in steels under cyclic loading

Abstract

A micromechanical model is proposed to describe the interactions between the microstructure and the dissipative deformation mechanisms in ferritic steels under cyclic loading. The model aims at optimizing the microstructure of steels since the dissipative mechanisms can be responsible for the initiation of microcracks. Therefore, a better understanding of the influence of the microstructure could lead to an improvement of fatigue properties. The dissipative mechanisms are assumed to be either anelastic (dislocation oscillations) or inelastic (plastic slip) and are described at the scale of the slip system using the framework of crystal plasticity. The macroscopic behavior is then deduced with a homogenization scheme. The model is validated by comparing the simulations with experimental results and is finally used to predict the impact of different microstructure parameters on the heat dissipation.

An energy method for rapid evaluation of high-cycle fatigue parameters based on intrinsic dissipation

“…As a consequence, it is of great significance to use intrinsic dissipation as a fatigue damage indicator with definite physical meaning to evaluate high-cycle fatigue parameters. Nevertheless, we should note that intrinsic dissipation is induced not only by microplastic deformation (unrecoverable microstructure motion), but also by internal friction (recoverable microstructure motion) such as the oscillation of dislocation loops, which does not contribute to the material fatigue damage [12][13][14][25][26][27][28].…”

“…The intrinsic dissipation under such stress condition is almost completely caused by internal friction and the fatigue life is deemed infinite [12][13][14]27,28]. On the contrary, for the alternating stress above the fatigue limit, microplastic deformation appears and induces fatigue damage .…”

“…On the contrary, for the alternating stress above the fatigue limit, microplastic deformation appears and induces fatigue damage . In this case, the intrinsic dissipation actually includes two parts: one caused by internal friction, and the other one caused by microplatic deformation [12][13][14]27,28]. Moreover, the latter is generally more sensitive than the former to the increase of the alternating stress amplitude, which can be explained by that microplastic deformation directly and significantly increases the degree of disorder of material microstructure (i.e.…”

Experimental and numerical study of the evolution of stored and dissipated energies in a medium carbon steel under cyclic loading

“…The dissipated and stored energies are found the highest for grains the most favorably oriented to slip for uniaxial compression according to the Schmid law. This effect, which has already been demonstrated by Mareau et al (2012) for dissipated energy, is however not sufficient to fully explain the heterogeneous aspect of the energetic fields.…”

Rate-dependent cyclic deformation of super-elastic NiTi shape memory alloy: Thermo-mechanical coupled and physical mechanism-based constitutive model

“…However, in order to obtain the material parameters from the stress-strain curves, the temperature field is regarded as uniform at a slow strain rate, e.g., 3.3×10 -4 /s, for simplicity. By such simplification, the parameters Referring to the existing literature (Mecking and Kocks, 1981;Mareau et al 2012), the physical constants, i.e., M, slip G ∆ , b , 1 k and 2 k are set to be 3, 2.5×10 -19 /J, 3.6×10 -10 m, 20×10 7 m and 5, respectively. The two parameters p and q are set as 0.1 and 1 by referring to Mareau et al (2012).…”