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Title:Retardation and repair of fatigue cracks in a microcapsule toughened epoxy composite -- Part II: In situ self-healing
Author(s):Brown, Eric N.; White, Scott R.; Sottos, Nancy R.
Subject(s):Fatigue cracks
Abstract:Successful arrest and retardation of fatigue cracks is achieved with an in situ self-healing epoxy matrix composite that incorporates microencapsulated dicyclopentadiene (DCPD) healing agent and Grubbs’ first generation Ru catalyst. Healing agent is released into the crack plane by the propagating crack, where it polymerizes to form a polymer wedge, generating a crack tip shielding mechanism. Due to the complex kinetics of healing a growing crack, the resulting in situ retardation and arrest of fatigue cracks exhibit a strong dependence on the applied range of cyclic stress intensity DKI. Significant crack arrest and life extension result when the in situ healing rate is faster than the crack growth rate. In loading cases where the crack grows too rapidly (maximum applied stress intensity factor is a significant percentage of the mode-I fracture toughness value), a carefully timed rest period can be used to prolong fatigue life up to 118%. At moderate DKI, in situ healing extends fatigue life by as much as 213%. Further improvements in fatigue life-extension are achieved by employing a rest period, which leads to permanent arrest at this moderate DKI. At lower values of applied stress intensity factor, self-healing yields complete arrest of fatigue cracks providing infinite fatigue life-extension.
Issue Date:2005-01
Publisher:Department of Theoretical and Applied Mechanics (UIUC)
Series/Report:TAM Reports 1061, (2005)
Genre:Technical Report
Publication Status:published or submitted for publication
Peer Reviewed:is peer reviewed
Date Available in IDEALS:2007-03-09
Is Version Of:Published as: Eric N. Brown, Scott R White, Nancy R. Sottos. Composites Science and Technology, Vol. 65, No. 15-16, 2005, pp. 2474-2480. DOI: 10.1016/j.compscitech.2005.04.053. Copyright 2005 Elsevier.

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  • Technical Reports - Theoretical and Applied Mechanics (TAM)
    TAM technical reports include manuscripts intended for publication, theses judged to have general interest, notes prepared for short courses, symposia compiled from outstanding undergraduate projects, and reports prepared for research-sponsoring agencies.

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