A model of the friction of a smooth hard surface sliding over a softer one

Friction modeling on multiple scales for deep drawing processes

“…The mean coefficient of friction is obtained for various contact pressures using the RFT as shown in Figure 7. 108 factor, f hk at the local asperity is found to be 0.6 which is also reasonable from the single asperity results of [47], [90] and [91] for ploughing and cutting modes of deformation (f hk = 0.5-0.9) in steel under lubricated conditions. The model predicts the trend of the friction with the contact pressure with a high degree of accuracy.…”

“…Hence, the boundary layers degrade at the local asperity scale during ploughing. Torrance et al [90] accounted for the degradation of the boundary layers by adding a term called fractional defect of the boundary layers, f d . The interfacial friction factor at the interface is given as…”

“…The error bar shows the variation due to the different surface measurements of the sheet material surface. To achieve the high friction factor estimated by [90] and [91] for local asperity conditions, the degradation factor (f d ) can be in the range of 0.5-0.7. The coefficient of friction increases with degradation of the boundary layers as shown in Figure 6.15.…”

A friction model for loading and reloading effects in deep drawing processes

“…While ploughing, there is a rupture of the boundary layers and it degrades at the local asperity scale. Torrance et al [38] accounted for the degradation of the boundary layers by adding a term called the fractional defect of the boundary layers, f d . The interfacial friction factor at the interface is given as…”

“…The error bar shows the variation due to the surface measurements made at different spots of the same sheet material surface. To achieve the high friction factor estimated by [38,39] for local asperity conditions, the degradation factor (f d ) can be in the range of 0.5-0.7. The coefficient of friction increases with degradation of the boundary layers as shown in Fig.…”