Wedge-shaped fracturing in the pull out of FRP stiffeners from quasi-brittle substrates

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:51

Article

Ballarini, Roberto¹  Franco, Annalisa²  Royer-Carfagni, Gianni² 

[1] Univ Minnesota, Dept Civil Engn, Minneapolis, MN 55455 USA

[2] Univ Parma, Dept Ind Engn, I-43100 Parma, Italy

关键词: Fiber Reinforced Polymer (FRP);    Stiffener;    Pull-out test;    Substrate cracking;    Inclined crack propagation;    Elasticity;    Complex potential;    Distributed dislocations;   

DOI  :  10.1016/j.ijsolstr.2014.05.015

来源: Elsevier

【 摘 要 】

Fiber-Reinforced-Polymer (FRP) strips can be glued to the surface of concrete or masonry structures to improve their strength. Pull-out tests on FRP bonds have shown a progressive failure of the adhesive joint involving early-stage cracking parallel to the axis of the FRP stiffener, and an inclined crack initiating at the free end of the stiffener and extending into the quasi-brittle substrate in the latest stage. The subsurface crack produces a characteristic wedge-shaped spall. There is no consensus on the reasons for the transition from cracking along the bond to cracking within the substrate. Therefore a Linear Elastic Fracture Mechanics model problem is presented here that accounts for and provides improved understanding of the formation of the subsurface crack. The boundary value problem is solved analytically using the distributed dislocation technique. Competition between crack extension along the adhesive joint and into the substrate is quantified using a quantized crack propagation criterion, whereby the crack does not advance in infinitesimal continuous increments, but instead in finite steps of length comparable to the characteristic dimensions of the material microstructure. The model predicts results that are in good agreement with experimental evidence. (C) 2014 Elsevier Ltd. All rights reserved.

【 授权许可】

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