Papers by Keyword: GFRP

Abstract: Glass fiber reinforced plastics (GFRP) are composite materials with high strength and flame retardancy, and the disposal process is expensive to cause illegal dumping. Therefore, new recycling technology of waste GFRP is desired. In this study, recycling of waste GFRP via pyrolysis with sodium hydroxide (NaOH) under an inert atmosphere using microwave heating was attempted by carbonization of resin and conversion of glass fiber into soluble sodium silicate. The pyrolysis behavior of GFRP, the characteristics of the obtained residue, and the silica extraction into the solution were compared for microwave heating and conventional heating. In both heatings, the carbonization of the resin and the conversion of the glass fiber into soluble sodium silicate were confirmed by pyrolysis with NaOH, and the sample after the pyrolysis treatment can be pulverized into a powdery residue by washing the solution without mechanical crushing. In comparison with conventional heating, microwave heating could reduce the time for heat treatment (41.3% reduction), to reduce the energy consumption (75% reduction), suggesting that microwave heating can provide more efficient treatment.

Abstract: The present Life Cycle Analysis (LCA) intends to investigate the environmental benefit of using natural fibres and/or recyclable epoxy resins for future manufacturing of small/medium wind turbine blades to handle thermoset polymer composites that are designed to be recyclable at the end of life”). LCA comparison of a modelled blade based on flax fibres reinforced recyclable epoxy resin and a traditional blade made of glass fibres and non recyclable epoxy resin is presented. In the production phase the environmental impacts of the flax fibre reinforced recyclable epoxy resin composite blade are higher than the blade based on glass fibre epoxy composite mainly due to the higher amount of epoxy resin necessary to satisfy the design criteria of the blade e.g. fatigue and deflection. The end of life is significative as the environmental impacts are reduced by the recycling and recovery of the fibres and the resin, being the resin more significative.

Abstract: There is an emerging need to upgrade historic masonry buildings and infrastructures which are most vulnerable to earthquakes. An objective of a long-term research program at Perugia University, Italy was developing design criteria for masonry reinforcement using a new class of materials, using Composite Reinforced Mortars (CRM). These are typically made of fiberglass meshes embedded into a cementitious or lime mortar, which offers higher sustainability features, in terms of vapour permeability and compatibility with masonry, lower costs, and better performance at high temperatures, compared to more traditional steel rebar jacketing or epoxy-bonded composites. These design criteria have been based on a comprehensive experimental and numerical research plan that included a study of the influence of reinforcing material, coating and wall thickness, and associated masonry strength and elastic properties, and the interaction of different stress states on bond behavior at interface masonry-to-coating. A design equation suitable for ultimate load design has been developed. Finally, analytical models regarding the lateral capacity of shear walls are briefly discussed.

Abstract: The strengthening and retrofitting of existing masonry built heritage has become an increasingly important issue in the last decades. Among the innovative solutions developed by the construction industry, the application of externally bonded fabric-reinforced cementitious matrix (FRCM) composites attracted a great interest, proving to be an easy, effective, and cost-efficient strengthening/retrofitting technique. FRCM composites were shown to be particularly suitable for applications on masonry due to the good compatibility between the composite inorganic matrix and the masonry substrate, which also promotes their durability.A crucial point for the effectiveness of externally bonded FRCM is the bond within the composite strip and between the composite and substrate. Indeed, composite debonding is the commonly observed failure mode. In order to improve the bond with the substrate, connectors (anchors) can be used to improve the bond capacity of the FRCM composite.In this paper, the mechanical and bond properties of a glass fiber reinforced polymer (GFRP) anchor spike, designed for FRCM strengthening, are investigated. First, tensile tests are performed to determine the elastic modulus and tensile strength of the anchor. Then, the anchor-masonry bond behavior is experimentally investigated using pull-out tests. Three different masonry substrates, namely a solid clay brick masonry, a tuff block masonry, and a stone masonry were adopted in the pull-out tests. The results show the influence of the substrate type on the anchor-masonry bond capacity and failure mode observed.

Abstract: The development of weight-efficient reusable launch systems has increased the urgency of problems associated with ultra-low-cycle fatigue. In this paper, one-sided three-point bending cyclic tests of GFRP specimens were performed. Parallel to the cyclic tests, registration of acoustic emission signals has been performed to identify the main damage mechanisms underlying ultra-low-cycle fatigue of fabric-reinforced composites. The obtained displacement-time diagrams showed a noticeable effect of creep on the deformation process. It was found that fiber fracture is the main mechanism of microdamage accumulation. A phenomenological three-element model based on the Norton-Bailey law and the Masing structural model was proposed. The model allowed describing both the deformation process of the specimens in time and their durability at different load levels. An optimization algorithm based on the deformable polyhedron method was used to find the optimal set of the model parameters.

Abstract: Recently, natural fiber reinforced polymer composites have become popular over traditional synthetic fiber reinforced polymer composites for automotive, low demanding structural and semi-structural applications. In this work, a comparative study of a natural fiber composite such as jute fabric composite (JFRP) and synthetic fiber composite such as glass fiber composite (GFRP) is presented. The composites were manufactured using hand lay-up and then curing at 90°C for 10 min in a hot press, followed by 24 h room temperature post-curing. The mechanical properties such as tensile and bending of JFRP and GFRP composites, were evaluated and compared. It was revealed that even if GFRPs exhibited significantly higher mechanical properties than JFRPs, environmental impact would still favor JFRPs for non-structural and low load bearing applications.

Abstract: The main issue in machining glass fiber reinforced polymers is a rapid wearing of the cutting tool caused by the superior properties of the fiber reinforcement within the matrix. Cooling in machining processes reduces tool wear and extends tool life. Cryogenic cooling is an alternative method for effective, environmentally friendly, clean and safe cooling. This paper studied the tool wear characteristics of carbide inserts coated with TiCN and Al₂O₃ in turning glass fiber reinforced epoxy resin pipe. The cutting parameters were various, with cutting speed, feed rate, depth of cut and cutting conditions (without cooling and with cryogenic cooling). Not all cutting speeds that were cooled under cryogenics showed good outcomes. However, the experimental results suggest that using high cutting speed at 1800 rpm and high feed rate at 0.13 mm/rev, together with cryogenic cooling, can reduce the flank wear of the tool compared with no cooling.

Abstract: For the design of vessels built by GFRP laminates, an insert with a viscoelastic layer is proposed to reduce the spread of damage produced by the vertical impact of the ship's bottom with the sea or slamming phenomenon. Using vertical drops-weight impact machine that reproduce the energy inferred to the panel during navigation, the propagation of the damage of OoA cured prepreg panels is studied comparing it with modified panels with insertion of viscoelastic layer. The use of acceleration data reading allows the benefits of viscoelastic modification during impact to be quantified through the developed formulation. The force, displacement and energy returned by the panel after impact have also been quantified, which does not become intralaminar and interlaminar damage. It is shown that under 40 joules of impact, the viscoelastic sheet has its best ability to return energy and above 130 joules it loses its capacity.

Abstract: Fibre reinforced polymers (FRPs) have emerged as popular materials for structural application in recent decades due to numerous of advantages. Despite the growing body of research on the use of glass fibre reinforced polymers (GFRP) composites in repairing and retrofitting the important structures such as oil and gas pipelines, the lack of comprehensive data on the long-term degradation mechanism for these materials is still impeding their widespread use in open-air structures repairs particularly in tropical climate locations such as Malaysia. Therefore, this paper presents an experimental investigation to determine the influence of tropical atmospheric condition on tensile properties of the GFRP. In this study, a set of GFRP samples were fabricated using epoxy resin as polymer matrix and woven E-glass fibres as reinforcing materials. These samples were exposed to tropical atmospheric condition in Malaysia for a period of four months. Tensile test was carried out for each sample before and after four-months period of exposure. The experimental tensile test results recorded a 15% reduction in tensile strength after 4 months of exposure as compared to its original strength. Further, the dominant failure mode of the exposed sample was characterized with longitudinal splitting of the fibres without completely breaking out. Overall, the tropical atmospheric condition has a noticeable impact on the GFRPs tensile strength degradations over the exposure duration.

Abstract: Glass fiber reinforced plastics (GFRP) are composite materials with high strength and flame retardancy, and the disposal process is expensive to cause illegal dumping. Therefore, new recycling technology of waste GFRP are desired. In this study, recycling of waste GFRP using pyrolysis with sodium hydroxide (NaOH) under an inert atmosphere was attempted by gasification of resin and conversion of glass fiber into soluble sodium silicate. The pyrolysis behavior of GFRP, the characteristics of the obtained residue, the composition and the yield of generated gas, and the silica extraction into the solution were investigated. As a result, the gasification of the resin and the conversion of the glass fiber into soluble sodium silicate were promoted by pyrolysis with NaOH. It was confirmed that the gas yield, especially flammable gases (H₂ and CH₄), and the silica extraction increased and the residual ratio decreased as the increase of the heating temperature, NaOH addition and heating time.