Prevention of Internal Cracks in Forward Extrusion by Means of Counter Pressure: A Numerical Treatise

2009-09-01
Soyarslan, C.
TEKKAYA, AHMET ERMAN
In the context of forward bulk extrusion, where product defects are frequently observed, the effect of counter pressure on damage accumulation materializing a Continuum Damage Mechanics (CDM) approach is presented. A Lemaitre variant damage model accounting for unilateral damage evolution coupled with a multiplicative finite plasticity is utilized for this purpose. After a presentation of the crack governing mechanism, it is demonstrated that application of counter pressure introduces a marked decrease in the central damage accumulation, which in turn increases the formability of the material through keeping the tensile triaxiality in tolerable limits. It is also shown that, for a crack involving process, through systematic increase of the counter pressure, the crack sizes diminish; and at a certain level of counter pressure chevron cracks can be completely avoided.

Citation Formats
C. Soyarslan and A. E. TEKKAYA, “Prevention of Internal Cracks in Forward Extrusion by Means of Counter Pressure: A Numerical Treatise,” STEEL RESEARCH INTERNATIONAL, vol. 80, no. 9, pp. 671–679, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/64874.