Environmental impact and embodied energy

Recent reports from the industry suggest that FRP has been the most cost effective solution at “first installed” cost in a few recent structures. Even if the “first installed’ cost of FRP solutions in not favourable compared to equivalent concrete/steel structures the life cycle cost and life cycle assessment analyses could be used to demonstrate cost and sustainability benefits of FRP structures. For instance, FRP bridge decks have advantages, such as controlled off-site fabrication, high strength, highfatigue and corrosion resistance, light weight, easy transportation, faster on-site assembly, minimisation of traffic disturbances,etc.; these could be used to off-set the initial cost, and to exploit the sustainable solutions offered by FRP materials

Experimental and numerical investigation of float glass–GFRP hybrid beams

Despite the great potentials of glass as a construction material, its brittle material behaviour poses major challenges to structural engineers when designing load-bearing glass structural members. This paper presents the load response and the failure behaviour of float glass–GFRP hybrid beams, when used as a mean of improving strength and ductility of float glass. Hybrid beams made from two layers of float glass sheets and an adhesively-bonded semi-transparent pre-cured GFRP interlayer were tested in four-point bending. The experimental results showed that double layer hybrid beams continued to take load even after the formation of the first major crack, and the beams were stronger and ductile than conventional single and multilayer float glass beams. Once the bottom glass layer has cracked the combination of the GFRP and the top glass layer carried the applied load whilst the gradual decrease in the stiffness due to the formation of new cracks ensures a ductile failure. Experimentally-validated finite element (FE) models that predict the evolution of stresses, stiffness and failure load of single and double layer glass beams, and glass– GFRP hybrid beams are also presented

A stress free model for residual stress assessment using thermoelastic stress analysis

Thermoelastic Stress Analysis (TSA) has been proposed as a method of obtaining residual stresses. The results of a preliminary study demonstrated that when Al-2024 plate containing holes that were plastically deformed by cold expansion process to 2% and 4% strain the thermoelastic response in the material around the hole was different to that obtained from a plate that had not experienced any plastic cold expansion (i.e. a reference specimen). This observation provides an opportunity for obtaining residual stresses based on TSA data. In many applications a reference specimen (i.e. residual stress free specimen) may not be available for comparison, so a synthetic, digital bitmap has been proposed as an alternative. An elastic finite element model is created using commercially available software Abaqus/Standard and the resultant stress field is extracted. The simulated stress field from the model is mapped onto a grid that matches the TSA pixel data from a physical reference specimen. This stress field is then converted to a ?T/T field that can be compared to the full-field TSA data. When the reference experimental data is subtracted from the, bitmap dataset the resultant ?T/T field is approximately zero. Further work proposes replacing the experimental reference data with that from specimens that have undergone cold expansion with the aim of revealing the regions affected by residual stress through a departure from zero in the resultant stress field. The paper demonstrates the first steps necessary for deriving the residual stresses from a general specimen using TSA

Composite riser design and development – a review

There is accelerating interest in composite risers for deepwater applications. Composite risers offer much higher strength to weight ratios over metallic risers but there is less experience of their behavior in deepwater environments. A general review on current developments specific to composite risers highlighting the remaining challenges and the applications, design evolution, state-of-the-art modeling and experimental techniques is lacking. This paper provides such a review on fiber-reinforced polymer composite risers. The major issues for composite risers are addressed including the complicated combination of loads under harsh deep sea environment, the lack of long-term material degradation database for assessing the reliability of these riser systems and the need of effective numerical models to fully account for complex realistic loading configurations. The paper also highlights current gaps for design and application of composite risers in off-shore technology and promising future research areas to help expand their utilization in deeper wate

Construction of full residual stress depth profile in glass using the knowledge of surface stress

This paper presents the development of a simple method to determine the full residual stress depth profile in architectural (i.e. construction sector) glass. The proposed model requires only the knowledge of the surface residual stress of glass, which can be known from the glass manufacturer or can be measured using a Scattered-Light-Polariscope (SCALP), as input. The requirement of through-thickness force equilibrium and the knowledge of parabolic shape of the residual stress depth profile are used to uniquely determine the residual stress depth profile in any given glass panel. Unlike the complex models reported in the literature, the proposed technique does not require modelling the complex multi-physics phenomenon of the generation of residual stress or the use of complex computational models. The residual stress predictions from the proposed model were validated against experimental results. The paper also presents a sensitivity analysis in order to justify the accuracy of the proposed model even after the possible errors/inaccuracies in the only input data (i.e. surface stress) of the model was incorporated in the analyses