Characteristics of dynamic friction and stress distribution in the cold rolling interface of aluminium strip based on fractal theory

This paper addresses the limitations of dynamic friction models in describing the force behaviour at the cold rolling interface. Using fractal theory, rolling theory, and load distribution theory, the study decouples the solid-liquid contact forces at the interface. Experimental data provided fractal parameters for aluminium surface roughness. A dynamic friction factor model incorporating surface roughness and metal flow velocity was developed. The study investigates the friction force and stress distribution at the aluminium cold rolling interface, revealing the dynamic friction factor varies with load, increasing along the rolling direction, and shows a more significant rise in the entry zone. The friction coefficient exhibits a monotonic increase with load, especially at lower reductions. The peak stress does not align with frictional force direction changes. The model's calculations closely match experimental data, with minor discrepancies in the exit zone.