Heavy-duty vehicles (HDVs), including lorries, buses, and coaches, are collectively responsible for more than 25% of the greenhouse gas (GHG) emissions generated by road transport in the EU, accounting for over 6% of the total GHG emissions in the EU. HDVs can benefit from the lightweighting approach commonly applied to body-in-white (BiW) components of passenger cars and truck cabins, by replacing conventional steel alloys with AHSS. These AHSS solutions are recognized as the most cost-efficient means of achieving lightweighting, resulting in weight reductions ranging from 18% to 35% and cost savings from 3 € to 10 € per kg. HDV chassis components represent almost 35% of the unladen weight of a rigid truck (12 tonnes gross vehicle weight) and have a significant potential for lightweighting, with the possibility of achieving weight reductions of at least 20%. However, the thin AHSS (< 3 mm) used in BiW cannot be directly applied to HDV chassis systems (chassis frame, suspension system and wheels) nor the chassis of light-duty vehicles (LDV) or passenger cars. These components must withstand cyclic loads and require higher thicknesses (> 3 mm), factors not considered in AHSSs for BiW. In contributing towards this goal, the aim of our study is to develop high-resolution digital microstructural models with crystal plasticity and damage mechanics to accurately represent the intricate microstructures of complex phases and new-generation steels. Crystal plasticity modelling offers a much more physically oriented description of mechanical behavior than the classical continuum mechanical description of plasticity. In this modelling approach, the grain morphology will be based on an artificially generated, simplified virtual microstructure (representative volume element), using the results of EBSD microstructure characterization. The effects of various microstructural features, e.g. grain boundaries, crystal lattice, and volume fraction, on macroscopic mechanical fatigue behavior will be examined. The effect of the initial residual stress will be modeled based on an initial distribution of geometrically necessary dislocations (GND). These models can enable integrated damage-fatigue assessments of these advanced steels, providing a comprehensive knowledge and data repository for further optimization of mechanical properties.