Composite pipes with various reinforcing structures, manufactured by RTM method

Mateusz Kozioł, Józef Śleziona

Quarterly No. 3, 2009 pages 244-249

DOI:

keywords: composite pipes, RTM method, reinforcing structure

abstract The paper presents the results of investigations on an effect of reinforcing structure on strength of composite pipes manufactured by RTM method. The pipes were manufactured by vacuum-aspiration RTM method, in 2-part aluminium mold, with removable tapered PVC core. Following reinforcement types were applied: 1) glass fibre fabrics: unidirectional of 350 g/m2, plain weave of 350 g/m2, and satin of 350 g/m2; 2) carbon fibre: plain weave fabric of 160 g/m2, satin sleeve of 215 g/m2. Epoxy resin was used as a composite matrix. Rings cut from the pipes were put to static compression tests into axial and radial directions. Fibre volume fraction was also measured. Comparative analyse of obtained results was carried out. It was found that RTM technology enable manufacturing of composite pipes of satisfactory quality. The manufactured pipes, reinforced with glass fibres and carbon fibres as well, show very good mechanical properties. The carbon fibre composites have significantly higher elastic modulus by radial compression, in comparison with glass fibre composites, by equivalent reinforcement stacking sequence in a pipe. An advantage of glass fibres, as a reinforcement in pipes, is „safer” failure progress by radial compression. Concerning strength and modulus, especially good is the unidirectional glass fabric reinforced composite. It shows very high strength and advantageous failure progress into radial direction. However, it shows only a bit lower strength into axial direction, when compared with the other composites. The carbon sleeve composite shows higher modulus and more advantageous failure progress by radial compression in comparison with the carbon fabric composite. However, it shows lower strength. Fibres volume fractions of the composites are not on satisfactory level. However, their mechanical properties should be aknowledged as very good. It testifies of grat potential of RTM method in range of manufacturing the composite pipes and it is necessary and purposeful to continue works leading to its modification. The works should incorporate mainly projecting and manufacturing of reinforcing preforms and molds, leading to an increase in fibre volume fraction of manufactured composites. The works descripted in this paper are preliminary stage of investigations aiming at an implement of the RTM method for mass production of high-strength, two-side smooth composite pipes.