Deep penetration of polycarbonate by a cylindrical punch

S. C. Wright, Y. Huang, N. A. Fleck*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


An experimental and theoretical investigation has been conducted to determine the deep penetration response of polycarbonate (PC). A series of low speed deep penetration tests was performed with steel punches to establish the load versus indentation response, and to enable detailed observation of the penetration processes. The effects of nose shape, lubrication and punch diameter were determined. We found that the average pressure on the indenting end of the penetrator is equal to 4-5 times the tensile yield stress and is independent of nose shape and penetrator diameter. A hackle zone of microcracked material extends to a diameter of 1.4 times that of the penetrator, and this is surrounded by a plastic zone which extends to a diameter of 3.5 times that of the penetrator. A model of deep penetration is developed, based on the assumption that the average pressure on the nose of the penetrator equals the pressure required to expand an infinitely small circular cylindrical void to the diameter of the penetrator. The model assumes the existence of an outer elastic zone, a plastic zone and a hackle zone surrounding the penetrator. The predicted penetration pressure and the diameters of the hackle and plastic zones are reasonably accurate.

Original languageEnglish (US)
Pages (from-to)277-284
Number of pages8
JournalMechanics of Materials
Issue number4
StatePublished - Aug 1992

ASJC Scopus subject areas

  • Materials Science(all)
  • Instrumentation
  • Mechanics of Materials


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