A novel method for estimating the fracture stress of ring specimens cut from polymer composite pipes is presented. The method applies image processing for determining the large displacements of the specimen. For image processing, photographs of the deformed specimen were taken before fracture, and a Fourier polynomial was fitted to the points of the digitalized cross section of the ring specimen. The presented mechanical model is based on the captured deformed shape, and it considers the geometrical nonlinearities of the problem. For stress calculation from bending moments, the Navier formula was selected. It was found that the developed method is capable of estimating the stress at break of polymer composite specimens under ring compression.
LukácsJ. Dimensions of lifetime management. Mater Sci Forum2005; 473-474: 361–368.
2.
SteinDRehabilitation and maintenance of drains and sewers. Berlin: Ernst & Sohn, 2001.
3.
KumarMAReddyGRBharathiYS. Frictional coefficient, hardness, impact strength, and chemical resistance of reinforced sisal-glass fiber epoxy hybrid composites. J Compos Mater2010; 44(26): 3195–3202.
4.
HullDSpencerB. Effect of winding angle on the failure of filament wound pipe. Composites1978; 9: 263–271.
5.
SodenPDKitchingRTsePCTsavalasYHintonMJ. Influence of winding angle on the strength and deformation of filament-wound composite tubes subjected to uniaxial and biaxial loads. Compos Sci Technol1993; 46(4): 363–378.
6.
NakamuraRGodaKNodaJOhgiJ. High temperature tensile properties and deep drawing of fully green composites. Exp Polym Lett2009; 3(1): 19–24.
7.
MészárosLRonkayFOláhL. Influence of extrusion temperature on thermal properties of polyamide 6/MMT nanocomposites. Plast Rubber Compos2008; 37: 219–222.
8.
BárányTFöldesECzigányT. Effect of thermal and hygrothermal aging on the plane stress fracture toughness of poly(ethylene terephthalate) sheets. Exp Polym Lett2007; 1(3): 180–187.
9.
CzélGCzigányT. Study of moisture absorption and mechanical properties of glass fibre/polyester composites – effects of specimen geometry and preparation. J Compos Mater2008; 42: 2815–2827.
10.
AbachaNKubouchiMSakaiT. Diffusion behavior of water in polyamide 6 organoclay nanocomposites. Exp Polym Lett2009; 3(4): 245–255.
11.
GuedesRMSáAFariaH. Influence of moisture absorption on creep of GRP composite pipes. Polym Test2007; 26(5): 595–605.
12.
WangCHTsaiCL. Source theoretical study for moisture diffusion in a carbon/epoxy composite laminate accompanied by thermal conduction. J Compos Mater2010; 44(18): 2233–2243.
Karger-KocsisJCastellaNGrishchukS. Hybrid resins from polyisocyanate, vinyl ester, melamine formaldehyde and water glass: structure and properties. Plast Rubber Compos2008; 37(5-6): 204–209.
15.
AllaouiAEl BouniaN. How carbon nanotubes affect the cure kinetics and glass transition temperature of their epoxy composites? – A review. Exp Polym Lett2009; 3(9): 588–594.
16.
KaddourASHintonMJSodenPD. Behaviour of ±45° glass/epoxy filament wound composite tubes under quasi-static equal biaxial tension–compression loading: experimental results. Compos Part B: Eng2003; 34(8): 689–704.
17.
CzélGCzigányT. Development and analysis of filament wound new composite pipes made of glass fibre reinforced 3P resin. Macromol Symp2006; 239: 232–244.
18.
ÖzbekPArgyrakisCLeeversP. Fracture mechanics analysis of arc shaped specimens for pipe grade polymers. Polym Testing2009; 28(3): 357–361.
19.
GuedesRMSáAde MouraMFSF. An experimental and numerical assessment of DCB tests on glass/polyester curved beams cut out from pipes. Polym Testing2008; 27(8): 985–994.
20.
TamásPGeršakJHalászMGrófG. Sylvie 3D drape tester - new system for measuring fabric drape. Tekstil2006; 10: 497–502.
21.
BeerFPJohnstonERJrDeWolfJTMazurekDMechanics of materials. 6th edn, New York: McGraw-Hill, 2009
