THE MIXED-MODE DELAMINATION OF FIBER COMPOSITE-MATERIALS

Citation
Aj. Kinloch et al., THE MIXED-MODE DELAMINATION OF FIBER COMPOSITE-MATERIALS, Composites science and technology, 47(3), 1993, pp. 225-237
Citations number
15
Categorie Soggetti
Material Science
ISSN journal
02663538
Volume
47
Issue
3
Year of publication
1993
Pages
225 - 237
Database
ISI
SICI code
0266-3538(1993)47:3<225:TMDOFC>2.0.ZU;2-P
Abstract
The present paper is concerned with an investigation of the mixed-mode delamination of polymeric fibre composite materials. Various test geo metries have been used to measure the interlaminar fracture energy, G( c), of both thermoplastic and thermosetting carbon fibre composites wh en subjected to various ratios of mode I to mode II loadings. In parti cular, the mixed-mode bending (MMB) delamination test has been studied in detail and the results from this test method compared to those obt ained from the fixed-ratio mixed-mode (FRMM) test method. Further, for the FRMM results, two methods of partitioning the measured interlamin ar fracture energy, G(c), have been employed: namely, by way of a loca l singular-field approach and by a global method based on a considerat ion of the applied energy release rates. It is shown that the latter a pproach is the more appropriate method. Finally, a general criterion f or mixed-mode failure is proposed which assumes that a crack loaded wi th G(I) and G(II) will have an induced mode I component equal to the f ailure value, termed G0, such that: G0 = G(c)[(cos2(psi - psi0) + sin2 omega sin2(psi - psi0)] where G(c) is the measured fracture energy, p si is the phase angle of the applied loads, psi0 is the phase angle wh ich arises from the elastic mismatch across a bimaterial interface (e. g. the fibre/matrix interface) and where omega can be regarded as the slope of the fracture surface roughness.