Hybrid modelling of sliding–sticking zones at the tool–chip interface under dry machining and tool wear analysis

Predicting periodic evolution of BUE formation mechanisms during machining ductile material using damage mechanics

“…For simplifying, it is assumed that temperature at the tool interface and the upper surface of BUE is same. According to the method introduced in (Bahi, et al, 2012), the thermal model at tool/chip interface is simplified by using the following assumptions: (1) the flank contact is neglected and (2) the heat flow through the tool surface is neglected. Such that ( 12 ) where is the heating sources, the frictional energy is assumed to be totally converted into heat and the heat due to plastic deformation in metal contact zone and friction in sliding zone are given by:…”

“…where is the shear stress in sticking zone, the thickness of secondary shear zone is supposed to be given by and , the value of is assumed to be of 0.1 in (Bahi, et al, 2012;Zhou, 2014), the following value is assumed to be of 0.1 in the present work. The chip velocity results from the incompressible condition of material flow, as…”

“…For the chip formation, the relation between cutting force and shear stress in the shear plane can be calculated as follows: ( 17 ) where is the shear stress at in Eq.9, the cutting width, the tool/chip global friction angle. The stress model mentioned in (Moufki, et al, 1998;Bahi, et al 2012) will be used to study the stress distribution and the contact length at the tool/chip interface. They can be assumed to have the following form: ( 18 ) where is the contact pressure distribution parameter, as an acceptable estimation (Karpat and Ozel, 2006).…”

“…The frictional behavior of the tool/chip interface in the metal contact is modeled (Sakuramoto, et al, 2012) as follow： ( 19 ) where is the frictional shear stress, the speed of transposition movement of chip atom, the memory function among the atoms, the number of transition in the real contact area of unit area . It can be noted that the apparent friction coefficient involves the whole loading on the tool/chip-workpiece contacts (Bahi, et al, 2012). In this model, the tool-workpiece contact is neglected, as .…”

Modelling the tuned criticality in stick-slip friction during metal cutting

“…This is mainly due to the repeated adiabatic shear bands in PSZ [10,11]. Meanwhile, the stick-slip friction also appears on the tool-chip interface in SSZ [12]. Thus, high-speed metal cutting is a multiple interaction, non-equilibrium system, strain rate effect is significant during that condition [13].…”