Interlaminar toughness composites

It is critical that surface treatment conditions be optimized to composite properties since overtreatment as well as undertreatment will degrade composite properties. Typically composite interlaminar shear strength (ILSS), in-plane shear, and transverse tension ate used to assess the effectiveness of surface treatment. More recently damage tolerance properties such as edge delamination strength, open hole compression, and compression after impact have become more important in evaluating the toughness of composite parts. 

Wang, Y. and J.G. Williams, Corrections for mode II fracture toughness specimens of composite materials. Composites Science and Technology, 1992. 43 p. 251-256. O Brien, T.K., Composite interlaminar shear fracture toughness, Gnc Shear measurement or sheer myth in Composite Materials Fatigue and Fracture 7. 

Johnson WS, Pavlick MM, Ohver MS. Determination of interlaminar toughness of IM7/977-2 composites at temperature extremes and different thicknesses. Georgia Institute of Technology 2005. Final report, 1—27. 

Fishpool DT, Rezai A, Baker D, Ogin SL, Smith PA. Interlaminar toughness characterisation of 3D woven carbon fibre composites. Plast Rubber Compos 2013 42 108-14. 

Kinloch AJ, Mohammed RD, Taylor AC, Sprenger S, Egan D (2006) The interlaminar toughness of carbon-fibre reinforced plastic composites using hybrid-toughened matrices. J Mater Sci 41(15) 5043-5046... 

Kinloch, A.J., Mohammed, R.D., Taylor, A.C., Sprenger, S., Egan, D., 2006. The interlaminar toughness of carhon-fihre reinforced plastic composites using hybridtoughened matrices. Journal of Materials Science 41 (15), 5043—5046. 

Fig. 5. Interlaminar fracture toughness, for a number of thermosetting and thermoplastic composites (36,37). Open white bars represent glass-fiber composites shaded bars are for carbon fibers. The materials are A, polyester (unidirectional) B, vinyl ester (CSM = chopped strand mat) C, epoxy (R/BR1424) D, epoxy (T300/914) E, PPS F, PES and G, PEEK. To convert J/m to fdbf/in. multiply by 2100.

A number of amorphous thermoplastics are presently employed as matrices in long fiber composites, including polyethersulfone (PES), polysulfone (PSU), and polyetherimide (PEI). AH offer superior resistance to impact loading and higher interlaminar fracture toughnesses than do most epoxies. However, the amorphous nature of such polymers results in a lower solvent resistance, clearly a limitation if composites based on such polymers are to be used in aggressive environments. 

ISO 14130 1997 Fibre-reinforced plastic composites - Determination of apparent interlaminar shear strength by short-beam method ISO 15024 2001 Fibre-reinforced plastic composites - Determination of mode I interlaminar fracture toughness, GIC, for unidirectionally reinforced materials... 

Historically, most attention has been devoted to mode I delamination growth to assess defects critically, as the first-generation composite systems exhibited low mode I fracture toughness when subjected to interlaminar normal stresses. The... 

ASTM D 5528 (1994). Mode I interlaminar fracture toughness of unidirectional fiber-reinforced polymer matrix composites. 

O Brien, T.K. and Martin, R.H. (1992). Results of ASTM round robin testing for mode I interlaminar fracture toughness of composite materials, NASA TM 104222. 

Summary of Mode I and Mode II interlaminar fracture toughness values for unidirectional carbon fiber 828 mPDA epoxy matrix composites with different fiber surface treatments ... 

Fig. 7.8. (a) Normalized impact fracture toughness and (b) interlaminar shear strength (ILSS) of carbon fiber-epoxy matrix composites as a function of glycidyl acrylate/methyl acrylate (GA/MA) interlayer... 

Fig, 7.16, Impact fracture toughness (O) and interlaminar shear strength (ILSS, ) of carbon fiber-epoxy matrix composites with varying number of nylon sheets as delamination promoters. After Havre (1977). 

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