An analytical model on the steady-state deformation of circular tubes under an axial cutting deformation mode

An analytical model for the steady-state axial cutting of circular tubes by a cutter with multiple blunt blades and without/with the presence of a curved surface profile deflector was developed. Experimental observations have indicated that there exist six different dissipation mechanisms. These include the outward bending of cut sidewalls, the formation of cylindrical flaps in the transient and stable cutting regions, circumferential membrane stretching, chip formation and friction. In the analytical model development, rigid-perfectly plastic material behaviour obeying the von Mises yield criterion was employed to determine the steady-state stresses and fully plastic bending moments for each deformation zone which were assumed to be uncoupled to each other. The effect of the friction force was included to the proposed solution and the total axial cutting force was determined through use of the principle of virtual power. The proposed analytical model was validated by comparing the predicted cutting force to experimental data and the effects of tube wall thickness, number of cutter blades, and extrusion diameter were investigated. A good correlation was found between the theoretical predictions and experimental observations.