THERMOMECHANICAL MODELING OF TURNING PROCESS USING AN ARBITRARY LAGRANGIANEULERIAN (ALE) METHOD

During turning processes, steels often behave in a complicated manner involving
severe plastic deformation, fracture, phase change and grain size change. It is a
complex process since there are several mechanisms work and interact
simultaneously. As the heat generated in the cutting process raises the work piece
material temperature above its critical phase transformation temperature, a
metallurgical transformation will occur, and the heat and plasticity due to the
transformation will affect the turning process. Mechanical deformation, heat transfer,
and microstructure are all strongly coupled and affected altogether, these effects has
been known thermo-mechanical coupling. There are several thermo-mechanical
variables such as stress, strain, and temperature that are not easily measurable through
the experimental test. These variables are induced the surface integrity of the work
piece material. In this research, two different 2D models; rectangle and circular are
developed with Arbitrary Lagrangian Eulerian (ALE) adaptive meshing. The
commercial finite element ABAQUS 6.8 is used for modelling of AISI 1045 steel
material by using carbide cutting tools. In finite element model, the tool is assumed as
analytical rigid and work piece is deformable body. The cutting speed was set as
100m/min, depth of cut of 3mm and feed rate of 0.15mm/rev. The Johnson cook law
material model is employed to simulate the flow stress of the work piece material.
The effect of three different rake angle (α = -10°, 0° and 10°), tool edge radius (r =
0.5mm, 1.0mm and 2.0mm) and friction coefficient (μ = 0.1 and 0.4) on von Mises
stress, equivalent plastic stain and temperature distribution were investigated. Based
on the results, the small rake angle of -10° tends to increase the von Mises stress,
equivalent plastic strain and temperature compared the larger rake angle; 0° and 10°.
The larger tool edge radius (2.0mm) influences the increasing of von mises stress,
equivalent plastic strain, and temperature distribution due to the close of the tool tip
and high plastic deformation on the work piece.