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The flexural stiffness characteristics of viscoelastically prestressed polymeric matrix composites

Pang, Jody W.C.; Pang, Jody W C; Fancey, Kevin; Pang, Jody W. C.; Fancey, Kevin S.

Authors

Jody W.C. Pang

Jody W C Pang

Jody W. C. Pang



Abstract

A novel composite material is described, where tension, applied to polymeric fibres, is released prior to moulding them into a matrix. On matrix solidification, compressive stresses imparted by the viscoelastically strained fibres improve mechanical properties. Previous studies showed that these viscoelastically prestressed composites had improved impact and tensile properties compared with control (unstressed) counterparts. In the current study, three-point bend tests on composites using nylon 6,6 fibre reinforcement in epoxy and polyester resins have demonstrated that the viscoelastic prestressing effect increases flexural stiffness. From deflections at 5 s and 900 s, using a freely suspended load on large span/thickness ratio (L/h) samples, the flexural modulus was increased by ∼50% relative to control counterparts. Stiffness-increasing mechanisms relating to pre-tensioned fibre and matrix prestress effects are discussed. For small L/h samples (using controlled rate deflection up to ∼5 s), the flexural modulus and resulting increase from viscoelastic prestressing were lower. This is attributed to shear effects and possibly fibre-matrix load transfer mechanisms. By exploiting time-temperature superposition, all samples were aged to the equivalent of 100 years at 20 °C and subsequent bend tests revealed no significant change in the modulus increase resulting from viscoelastic prestressing. © 2009 Elsevier Ltd. All rights reserved.

Journal Article Type Article
Publication Date 2009-07
Journal COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
Print ISSN 1359-835X
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 40
Issue 6-7
Pages 784-790
APA6 Citation Pang, J. W. C., & Fancey, K. S. (2009). The flexural stiffness characteristics of viscoelastically prestressed polymeric matrix composites. Composites Part A: Applied Science and Manufacturing, 40(6-7), (784-790). doi:10.1016/j.compositesa.2009.03.009. ISSN 1359-835X
DOI https://doi.org/10.1016/j.compositesa.2009.03.009
Keywords A. Polymer–matrix composites (PMCs); B. Mechanical properties; Viscoelasticity
Publisher URL https://www.sciencedirect.com/science/article/pii/S1359835X09000785?via%3Dihub
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