Fiber Reinforced Polymer Layers Research Articles

Rectangular Filament-Wound Glass Fiber Reinforced Polymer Tubes Filled with Concrete under Flexural and Axial Loading: Analytical Modeling

This paper presents an analytical model to predict the behavior of concrete-filled rectangular fiber reinforced polymer (FRP) tubes (CFRFTs), subjected to bending and axial loads. The model accounts for different laminate structures of the flange and web of the tube. Gradual reduction of stiffness, resulting from progressive failure of FRP layers oriented at various angles is considered through the ultimate laminate failure approach. The model adopts cracked section analysis, using layer-by-layer approach and accounts for totally and partially filled tubes. The model predicts the moment–curvature responses of beams, load–strain responses of columns, and complete interaction curves of beam–columns. The model is verified using experimental results and is used to study the effects of laminate structure, hybrid laminates, thickness of the tube and optimization of partially filled tubes. Comparisons of CFRFT with conventional reinforced concrete (RC) sections showed that CFRFT could provide axial load–bending ...

Confinement Model for Axially Loaded Short Rectangular Columns Strengthened with Fiber-Reinforced Polymer Wrapping

A confinement model, describing the behavior of rectangular concrete columns retrofitted with externally bonded fiber-reinforced polymer (FRP) material and subjected to axial stress, is presented. The derivation of the proposed model is based on the findings of an extensive experimental investigation involving the testing of 90 rectangular specimens representing 3 cross-sectional aspect ratios, 2 concrete strengths, and 5 different numbers of FRP layers. The proposed model is trilinear, both in the axial and lateral directions, and captures the key parameter observed; namely, the ratio of the stiffness of the FRP jacket in the lateral direction to the axial stiffness of the column. The proposed model was found to fairly accurately describe results reported in other similar research studies.

Applications of fiber‐metal laminates

AbstractAdvanced composite materials and fiber‐metal laminates (FMLs) have the potential to offer significant improvements in weight savings and durability in airframe structures. FMLs are an advanced hybrid material system consisting of metal layers bonded with fiber‐reinforced polymer layers. This paper presents an overview of the history of fibre‐metal‐laminates, describes several common types and also discusses the results of impact durability experiments conducted at the Structures, Materials and Propulsion Laboratory of the Institute for Aerospace Research (SMPL‐IAR) of the National Research Council Canada (NRCC). An impact fixture was developed specifically for FMLs and is also described. Numerous low velocity impact tests have been carried out that demonstrate the improved impact response of FMLs over traditional composite materials. This research builds upon earlier impact testing on carbon‐fiber‐reinforced polymers conducted by NRCC and Carleton University.

Externally Bonded Fiber-Reinforced Polymer for Rehabilitation of Corrosion Damaged Concrete Beams

This paper reports the results of an experimental program designed to provide a realistic assessment of the potential of using fiber-reinforced polymer (FRP) materials in the repair and strengthening of reinforced concrete (RC) flexural members. The experimental program included seven RC flexural beams, 270-by-400 mm in cross section and 4,350 mm in length. Four of the seven RC beams were reinforced externally with one or two layers of carbon FRP (CFRP) composite. Variables considered included state of damage (damaged versus undamaged) and loading condition during bonding (loaded versus unloaded). Damage was introduced in four of the seven RC beams using an accelerated corrosion technique developed at the University of Toronto. Test results revealed that it is necessary to consider the effects of corrosion- and load-induced damage as well as sustained load on the load-carrying and deflection capacities of externally reinforced flexural members. Furthermore, it is concluded that it is possible to achieve adequate corrosion repair with externally bonded CFRP and minimal intervention. In particular, results showed that it is important to optimize CFRP layout to balance strength recovery with control of faulting and splitting, which could lead to premature member failure.