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

Date

2009-09-01

Author

Soyarslan, C.
TEKKAYA, AHMET ERMAN

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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.

Subject Keywords

Forward extrusion, Counter pressure, Chevron cracks, Ductile damage, Finite elements

URI

https://hdl.handle.net/11511/64874

Journal

STEEL RESEARCH INTERNATIONAL

DOI

https://doi.org/10.2374/sri08sp170

Collections

Department of Civil Engineering, Article

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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, pp. 671–679, 2009, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/64874.