Analysis of Steel Phase Transformations Using a Multiscale Transient Model
Multiphase steels offer impressive mechanical properties. However, their characterization still represents a challenge. In a quenching processes, phenomena such as undesirable strains or residual stress are inevitable and can be the cause for non-admissible final parts. Microstructural phase transformations generally magnify the problem. This fact leads to the need of numerical tools capable of quantifying these residual stresses, due to the non-existence of efficient non-destructive experimental procedure capable of measuring them. In this work, a numerical multiscale transient model, that uses the Asymptotic Expansion Homogenisation (AEH) method combined with finite element method (FEM), is proposed. The implementation of the AEH method is carried out using the commercial program Abaqus, considering an uncoupled and quasi-static transient problem with implicit time integration. Within the homogenisation method, the existence of two distinct scales is assumed, defining a micro and a macroscale. Within the smaller scale, the evolution of a steel periodic microstructure is analysed in detail and an equivalent homogeneous material model is established for macroscopic use. However, the microstructural evolution leads to the need of new equivalent homogeneous models in order to predict the macro response. Consequently, several mechanical, thermomechanical and transient thermal homogenization procedures are carried in order to establish different equivalent homogeneous models.
Aldo Ofenheimer, Cecilia Poletti, Daniela Schalk-Kitting and Christof Sommitsch
B. Barroqueiro et al., "Analysis of Steel Phase Transformations Using a Multiscale Transient Model", Key Engineering Materials, Vols. 651-653, pp. 545-551, 2015