Numerical analysis of axisymmetric wire drawing by means of a coupled damage model

A modified damage work model has been implemented into a finite element analysis, by means of a developed Fortran subroutine. This has enabled the analysis of the occurrence of central burst defects in single and multipass wire drawing. The die land has been shown to have a negligible effect on both the mechanical properties of the wire and the required drawing load. The increase in axial damage with increasing friction is greatest for long dies and less significant for shorter dies. When central bursts occur, the mean die pressure fluctuates periodically with increased drawing length, with the wavelength of the oscillations coinciding with the distance between two successive central bursts. In addition to periodic fluctuations in the hydrostatic and effective stress distributions along the central axis of the wire, central bursting results in periodic variations in the effective strain along the surface of the wire. These variations in wire diameters are thought to be indicative of ‘bamboo defects’, which are often an external indication of central bursts.