Evaluation of GFRP Repairs Through Monotonic Tensile Testing
Repairs are carried out on wind turbine blades and boats manufactured with glass fiber reinforced polymer composites either as a part of the manufacturing process or when they get damaged during service. These repairs experience various static and cyclic loading modes when the repaired part or structure is put back into service. This study consists of evaluation of repairs with varying repair parameters conducted on glass fiber reinforced polymer (GFRP) composites. The repair parameters examined were depth of grinding carried out for surface preparation to carry out repairs, the resin used for repair and use of interlaminar layers. Monotonic tensile testing was carried out on tensile GFRP composite specimens with simulated scarf repairs on both sides to maintain symmetry while testing. The specimens were designed in such a way so that the closed form of an interfacial crack in a bilayer could be applied to calculate the fracture toughness. Data such as peak loads at a defined failure criterion during crack propagation and crack initiation fracture toughness values was used to compare the different kinds of repairs. Digital image correlation software (Vic-2D) was used for some measurements. The data thus gathered is being used for further characterization of GFRP repairs by subjecting them to fatigue loading of similar specimens in tension. The design and preparation of specimens and results of testing along with the effects of the changes in the repair parameters will be discussed in this technical paper.
Authors: Varman Joseph, Robert Kearney, Tanveer Chawla
Conference: CAMX 2016 – Anaheim