High Strain Rate Testing in Yarns

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Authors
  1. Dabboussi, W.
  2. Dooraki, B.F.
  3. Nemes, J.A.
Corporate Authors
Defence R&D Canada - Valcartier, Valcartier QUE (CAN);McGill Univ, Montreal QUE (CAN) Dept of Mechanical Engineering
Abstract
This report contains a description of a Hopkinson bar device, which has been designed specifically for the testing of yarns at high strain rates. The Hopkinson bar consists of a gas gun, striker/incident bar assembly, the transmitted bar assembly and the attachment mechanism. The design of the yarn attachment mechanism is particularly challenged since a method must be found that does not allow the yarn to slip and at the same time does not cause premature failure. In addition, the attachment must result in a relatively small gage section. Several attachment mechanism designs are presented. The final design uses a combination of mechanical and epoxy means of attachment, and is shown to be quite robust and give repeated results. The Hopkinson bar device is demonstrated by testing Kevlar KM2 yarn. Specimen designs consisting of both 4 and 6 yarns are used. To assess the rate-dependant behaviour of the yarns, quasi-static tests are performed on a hydraulic test machine using the same yarn attachment mechanism. The results obtained indicate that yarn strength is highly rate-dependant, which is consistent with previously published results.
Report Number
DRDC-VALCARTIER-CR-2006-665 — Contractor Report
Date of publication
01 Feb 2003
Number of Pages
29
DSTKIM No
CA029549
CANDIS No
527927
Format(s):
CD ROM;Document Image stored on Optical Disk

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