Accelerated and real-time creep and creep-rupture results for aramid fibers

Giannopoulos, IP; Burgoyne, CJ

dc.contributor.author	Giannopoulos, IP	en
dc.contributor.author	Burgoyne, CJ	en
dc.date.accessioned	2014-03-01T02:07:34Z
dc.date.available	2014-03-01T02:07:34Z
dc.date.issued	2012	en
dc.identifier.issn	00218995	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/29578
dc.subject	accelerated testing	en
dc.subject	creep	en
dc.subject	creep rupture	en
dc.subject	Kevlar 49	en
dc.subject	stepped isostress method	en
dc.subject	stepped isothermal method	en
dc.subject	Technora	en
dc.subject.other	Accelerated testing	en
dc.subject.other	Creep ruptures	en
dc.subject.other	Kevlar 49	en
dc.subject.other	stepped isostress method	en
dc.subject.other	Stepped isothermal methods	en
dc.subject.other	Technora	en
dc.subject.other	Activation energy	en
dc.subject.other	Creep	en
dc.subject.other	Creep testing	en
dc.subject.other	Isotherms	en
dc.subject.other	Materials testing	en
dc.subject.other	Textile fibers	en
dc.subject.other	Yarn	en
dc.subject.other	Aramid fibers	en
dc.title	Accelerated and real-time creep and creep-rupture results for aramid fibers	en
heal.type	journalArticle	en
heal.identifier.primary	10.1002/app.36707	en
heal.identifier.secondary	http://dx.doi.org/10.1002/app.36707	en
heal.publicationDate	2012	en
heal.abstract	This article presents results from conventional creep tests (CCT) and two accelerated test methods (the stepped isothermal method (SIM) and the stepped isostress method (SSM)) to determine the creep and creep-rupture behavior of two different aramid fibers, Kevlar 49 and Technora. CCT are regarded as the true behavior of the yarn, but they are impractical for long-term use where failures are expected only after many years. All the tests were carried out on the same batches of yarns, and using the same clamping arrangements, so the tests should be directly comparable. For both materials, SIM testing gives good agreement with CCT and gave stress-rupture lifetimes that followed the same trend. However, there was significant variation for SSM testing, especially when testing Technora fibers. The results indicate that Kevlar has a creep strain capacity that is almost independent of stress, whereas Technora shows a creep strain capacity that depends on stress. Its creep strain capacity is approximately two to three times that of Kevlar 49. The accelerated test methods give indirect estimates for the activation energy and the activation volume of the fibers. The activation energy for Technora is about 20% higher than that for Kevlar, meaning that it is less sensitive to the effects of increasing temperature. The activation volume for both materials was similar, and in both cases, stress dependent. Copyright © 2012 Wiley Periodicals, Inc.	en
heal.journalName	Journal of Applied Polymer Science	en
dc.identifier.doi	10.1002/app.36707	en
dc.identifier.volume	125	en
dc.identifier.issue	5	en
dc.identifier.spage	3856	en
dc.identifier.epage	3870	en