Fibers and Polymers

, Volume 2, Issue 1, pp 18–21 | Cite as

Neck formation in drawing processes of fibers

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Abstract

To better understand the formation of necking in drawing processes of fibers, strain distributions during drawing processes have been analyzed. For simplicity, one-dimensional incompressible steady flow at a constant temperature was assumed and quasi-static model was used. To describe mechanical properties of solid polymers, non-linear visco-plastic material properties were assumed using the power law type hardening and rate-sensitive equation. The effects of various parameters on the neck formation were mathematically analyzed. As material property parameters, strain-hardening parameter, visco-elastic coefficient and strain-rate sensitivity were considered and, for process parameters, the drawing ratio and the process length were considered. It was found that rate-insensitive materials do not reach a steady flow state and the rate-sensitivity plays a key role to have a steady flow. Also, the neck formation is mainly affected by material properties, especially for the quasi-static model. If the process length changes, the strain distribution was found to be proportionally re-distributed along the process line by the factor of the total length change.

Keywords

Necking Drawing process Quasi-static Rate-sensitivity 

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Copyright information

© The Korean Fiber Society 2001

Authors and Affiliations

  1. 1.School of Materials Science and EngineeringSeoul National UniversitySeoulKorea

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