engleski

FRP composites property degradationdue to marine environment exposure

Fiber reinforced polymer composites (FRP) coupons have been exposed to real sea environment in order to assess the influence to the mechanical behavior of composite materials used in the construction of marine vessels and structures. Real life sea environment conditions were opted for instead of the more common simulated and laboratory versions of seawater in the attempt to obtain more realistic structural modeling environmental input parameters for the design of such structures. Also, exposure was performed over prolonged time span, instead of usual accelerated tests. Epoxy and polyester resins, reinforced with glass fibers in three fiber layout configurations were used to manufacture standardized tensile testing coupons. Vacuum assisted infusion and hand layup processes were used to manufacture the coupons. Mass changes due to seawater absorption, microorganism’s growth, changes in tensile strength (standard tensile tests) and surface morphology (using optical and scanning electron microscopy) of the coupons were evaluated after 6- and 12-months long periods of submersion in the sea in the Rijeka bay. All specimens have shown mass increase due to water absorption and growth of attached algae and sea microorganisms. Various levels of reduction in tensile strength, depending on the fiber layout configurations, were observed. Significant changes in the matrix material structure were noticed due to forming of salt crystals and microorganisms feeding on the organic resins, effectively producing “voids” in the matrix material.

FRP, real marine environment, mechanical properties

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