Three-dimensional elastic-plastic finite element analysis for orthogonal cutting with discontinuous chip of 6-4 brass

An elastic-plastic finite element model is developed for 3D orthogonal cutt ing of discontinuous chips. The tool is P20 while the workpiece is made of 6-4 brass. Examined under the condition of low cutting speed are the initia l crack location, the direction of crack growth and variations of discrete chips. These predictions are made possible by application of the strain ene rgy density (SED) theory. The initial crack was formed above the tool tip a nd grew progressively along the stationary values of the SED function until the trajectory intersects with the free surface. The plastic deformation a nd friction result in a high equivalent stress in the secondary deformation zone of the first longitudinal chip. Stresses are also high at the locatio n of crack initiation. The chip node near the tool face is sensitive to the contact of the tool face. As more residual stress prevails after the first longitudinal cut, degradation of the workpiece surface prevails and should be accounted for. (C) 2001 Elsevier Science Ltd. All rights reserved.