Multiscale analysis of microstructure-based bending characteristics of advanced high strength dual-phase steel

Different stress states have a significant influence on the magnitude of the microscopic plastic strain and result in the development of the microstructure evolution. As a result, a comprehensive understanding of the different scale variation on microstructure evolution during bending deformation is essential. The advanced high strength dual-phase (DP1180) steel was investigated using multiscale microstructure-based 3D representative volume element (RVE) modelling technology with emphasis on understanding the relationship between the microstructure, localised stress–strain evolution as well as the deformation characteristics in the bending process. It is demonstrated that the localised development in bending can be more accurately described by microscopic deformation when taking into account microstructural properties. Microstructure-based 3D RVEs from each chosen bending condition generally have comparable localisation properties, whilst the magnitudes and intensities differ. In addition, the most severe localised bands are predicted to occur close to the ferrite and martensite phase boundaries where the martensite grains are close together or have a somewhat sharp edge. The numerically predicted results for the microstructure evolution, shear bands development and stress and strain distribution after 3-point bending exhibit a good agreement with the relevant experimental observations.