Investigation of the Transition From Plane Strain to Plane Stress in Orthogonal Metal Cutting

Abstract

It is widely known that in practical orthogonal machining experiments, interior sections of the deforming material undergo plane strain deformation whereas material near the side faces of the workpiece undergoes plane stress deformation. This study is aimed at investigating the plane strain to plane stress transition using 3D coupled thermo-mechanical finite element analysis of orthogonal machining. The temperature, stress, strain and strain-rate distributions along different planes of the workpiece are analyzed to obtain estimates of the fraction of material undergoing plane strain deformation for different widths of cut. While it is found that the deformation in the mid-section of the workpiece is close to that observed in 2D plane strain simulations, the deformation along the side faces is quite different from that observed in 2D plane stress simulations, due to the constraint imposed upon the material along the sides by the material in the middle. Though the chip thickness along the sides is smaller than the chip thickness in the middle, the strain, strain-rate, and temperature fields along the side face and mid-section are quite similar. This study confirms that accurate maps of temperature, strain and strain-rate in plane strain deformation can be obtained by observing the side faces. It is found that for the cutting conditions used, a width to depth-of-cut ratio of twenty (not ten, as is commonly assumed) results in a close approximation to plane strain deformation through more than 90% of the width of the work material. For a width to depth-of-cut ratio of ten, significant deviations are observed in the stresses, with respect to their corresponding values in plane strain. Recommendations for the width of cut to depth of cut ratio to be used in experiments for other cutting conditions can be developed based upon similar studies.

Machining simulation of Ti6Al4V using coupled Eulerian-Lagrangian approach and a constitutive model considering the state of stress

“…According to Liu et al [53], the stress and strain distributions are uniform in the interior of the chip/machined part, while in the border (the interface between the material and the void in the CEL model) these distributions change significantly. Pednekar et al [54] show that, when the ratio between the width of cut and the uncut chip thickness reaches a critical value of 20, more than 90% of the chip width can undergo plane strain conditions. The model shown in Fig.…”

Characterization of the material-induced elastic–plastic deformations in ultra-precision diamond cutting

“…In the second mechanism, the workpiece material under a high temperature experiences severe plastic deformation and flows through the trailing edge to the side of the cutting tool. For the second generation mechanism, the occurrence of side flow is favored by a higher cutting speed [23,25,26] and increased by the tool wear in the secondary edge [27]. Besides,cutting forces and chip morphology also were found to make a great effect on material side flow.…”

Regression Modeling of the Effect of Chip Slenderness Ratio and Cutting Parameters on Vibration

“…Yapmış olduğu çalışmada sonlu elemanlar yöntemi elde ettiği model üzerinden Pednekar ve ark. bu oranın 20'ye kadar çıkarılabileceğini iddia etmiştir [5]. Ancak her türlü iş parçası malzemesi ve kesme koşulu için, anılan çalışmalarda herhangi bir kritik ve kesinleştirilmiş oran belirlenememiştir [1].…”