Analysis of the tensile behaviour of viscoelastically prestressed polymeric matrix composites

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

Abstract

A novel composite material is reported, in which tension, applied to polymeric fibres, is released prior to moulding them into a matrix. Following matrix solidification, compressive stresses imparted by the viscoelastically strained fibres impede crack propagation. Previous Charpy impact studies had demonstrated that these viscoelastically prestressed composites could absorb typically 25-30% more energy than control (unstressed) counterparts and the current study focuses on their tensile behaviour as a function of fibre volume fraction, V f . Tensile testing was performed on continuous unidirectional nylon 6,6 fibre-epoxy resin samples. Compared with control counterparts, the results showed that viscoelastic prestressing improved tensile properties, the effects being V f -dependent. Increases in tensile strength, modulus and energy absorbed (to 0.25 strain) exceeded 15%, 30% and 40%, respectively, at an optimum V f , this being ∼35-40%. Strain-to-failure was reduced by 10-20%, thereby lowering any improvement in tensile toughness (energy absorbed to fracture) to < 10%. Mechanical properties of the fibres themselves were not significantly influenced by the treatment used for generating composite prestress, and we propose that the observed improvements to tensile properties may be attributed to: (i) direct contribution from compressive stress, (ii) attenuation of the dynamic overstress effect on fibre fracture and (iii) improved mechanical integrity through a more collective response from fibres to tensile loads. © 2008 Elsevier Ltd. All rights reserved.

Citation

Pang, J. W. C., & Fancey, K. S. (2008). Analysis of the tensile behaviour of viscoelastically prestressed polymeric matrix composites. Composites Science and Technology, 68(7-8), 1903-1910. https://doi.org/10.1016/j.compscitech.2007.12.018

• Journal Article Type: Article
• Acceptance Date: Dec 22, 2007
• Online Publication Date: Jan 15, 2008
• Publication Date: 2008-06
• Journal: COMPOSITES SCIENCE AND TECHNOLOGY
• Print ISSN: 0266-3538
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 68
• Issue: 7-8
• Pages: 1903-1910
• DOI: https://doi.org/10.1016/j.compscitech.2007.12.018
• Keywords: General Engineering; Ceramics and Composites
• Public URL: https://hull-repository.worktribe.com/output/395977
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S026635380800002X?via%3Dihub