FRP-Glass Composite Structures

Lead Research Organisation: University of Cambridge
Department Name: Engineering

Abstract

Glass is a ubiquitous material in building envelopes, where it is typically used in multiple flat plates to form insulated glazing units (IGUs) that are simply supported by rectilinear framing members. Despite recent technological improvements in this field, state-of-the-art glazing systems fail to make efficient use of materials, have a low robustness, a relatively high thermal conductivity, and are rarely recycled.
Recent research developments in glass engineering, adhesive bonding and fibre-reinforced polymer (FRP) composites provide an opportunity to explore a novel combination of these materials in the form of FRP-glass composite structures. These consist of glass plates that are bonded to pultruded FRP profiles by means of high strength - high stiffness thermosetting adhesives, thereby forming an FRP-glass composite panel . This is a novel, yet relatively simple concept, but it involves a radical shift in the role of glass in buildings: from its current use as an inefficient infill panel in a layered system, to a structurally and thermally efficient component within a robust and recyclable composite structure.
The aim of this 24 month project is two-fold: Firstly to characterise the thermo-mechanical properties and environmental impact of a first generation, yet novel, form of composite FRP-glass panel; and secondly to explore the feasibility of more adventurous second generation composite glass panels. The latter offer further improvements over the basic FRP-glass panels, in terms of structural performance, adaptability and recyclability. This aim will be achieved by means of coordinated thermo-mechanical investigations involving physical experiments, numerical modelling and theoretical analyses at three levels: (1) material level, (2) FRP-glass connection level; and (3) full-scale composite glass panel level,
The evaluation of the potential benefits of composite glass panels and the fundamental properties characterised in this project will: (1) provide a basis for future research and product development in this new sub-field; (2) help produce novel glazed building envelopes that significantly out-perform existing state-of the-art glazing systems; (3) lead to step-change improvements in the sustainability and resilience of new and existing buildings.

Planned Impact

This project proposes a novel combination of FRP and glass which if successful, would ultimately lead to step-change improvements in the sustainability and resilience of existing and future buildings. The impacts in the built environment will be technological (novel form FRP-glass components), societal (resilient and more efficient buildings), economical (cheaper and thinner building envelopes) and environmental (thermal performance of buildings, minimise materials usage, recyclability). This research will also have impacts in sectors where glass is used in conjunction with other materials (e.g. automotive and consumer products).
 
Description The key findings of the research cover three areas (Experimental outputs, Analytical models and Partnerships & Grants) and are described in the following. EXPERIMENTAL OUTPUTS: 1) Buckling/Bending experiments on straight FRP-glass components have provided novel data and key information on the structural benefits of the composite action between components, 2) Optimum surface treatment and milling of FRP profiles have been investigated to maximize adhesion between FRP and glass substrates , 3) Thermal performance (U-value) of FRP-glass composite panels for building facades has been characterized in Hot-Box experiments and the results show substantial reductions in undesirable thermal transmittance compared to traditional glazing components, 4) Cold-bent FRP-glass panels for free-form facades have been successfully assembled at lab scale and buckling phenomena (leading to visual distortions) has been better understood by comparison with numerical modelling, 5) Creep of adhesives in FRP-glass joints has been experimentally investigated for real service loads. ANALYTICAL MODELS: 1) Models of bending rigidities and shear stiffness have been developed and published, and have been successfully applied to predict the bending and buckling behaviour of FRP-glass components, 2) The developed models have provided a spreadhsset-based tool for designing FRP-glass components, particularly for adhesive selection (i.e. adhesives stiff enough to activate the composite action, yet flexible enough to reduce stress concentrations). PARTNERSHIPS & GRANTS: 1) Key industrial partners (engineering firm and manufacturers of glass, FRP and adhesive), all world-leaders in their sector, have joined the research, 2) EPSRC Follow-on Fund has been recently secured to continue the research, in close collaboration with the industrial partners, to develop the FRP-glass reseatch to a stage where it can be commercialized.
Exploitation Route The findings of this research can be taken forward in several ways, as follows: 1) The authors will continue the research (with a recently secured EPSRC Follow-on Fund) in order to explore the feasibility of up-scaling FRP-glass facade units for cladding of real-world buildings, 2) Additional research on FRP-glass structures can be performed, particularly in relation with adhesively-bonded joints (disassembling, bio-based resins, life-cycle analyses and dynamic loading), 3) Engineering firms can use and extend the (open-source) analytical models in order to design complex sandwich-like structures, e.g. box girder-deck bridge or frame-core high rise building, 4) Designers of glass structures can find valuable data on the bending/buckling structural capacity of glass beams/columns, 5) Consumer porduct designers, automotive negineers and others where glass is used in conjunction with polymeric chassis / frames can use and take forward the adhesively-bonded FRP-glass concept in order to design lightweight, robust and mechanically slim electronic devices / vehicles with a strong FRP frame acting compositely with a transparent glass screen.

Some of these areas of further R&D have been incorporated into a recent H2020 research proposal called SLIMglass, submitted by Cambridge and a consortium of academic and industrial partners in Feb 2019. Currently awaiting outcome.
Sectors Aerospace, Defence and Marine,Construction,Electronics,Energy,Manufacturing, including Industrial Biotechology,Transport
URL http://dx.doi.org/10.1016/j.compstruct.2016.10.059
 
Description The significant benefits offered by FRP-Glass structures first identified and disseminated during this EPSRC-funded research have been noted by key global companies in the supply chain. We are now partnering with these industrial partners to undertake fuhrer research (at higher TRLs) that will demonstrate the benefits of FRP-Glass structures at building scale. If successful, this would lead to a new generation of slim, lightweight and energy efficient glazing that significantly outperforms existing glazing systems. We have teamed up with industrial partners Arup (UK), Kommerling (UK & Germany), Dow Corning (UK & USA) and AGC Interpane (Germany) to construct two full scale (3m by 1.5m) prototypes of the novel FRP-Glass panels and we have exhibited them in the emerging technologies area of the world's premier glass technology fair in Dusseldorf, Germany in October 2018. Exhibiting in the emerging technologies area is by invitation-only and our FRP-Glass prototypes was one of only five emerging technologies globally that were selected for this exhibition. The prototypes generated significant interest and we are currently following up on these real-world opportunities.
First Year Of Impact 2018
Sector Construction
Impact Types Economic
 
Description EPSRC Impact Accelerator Follow-on-Fund
Amount £59,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2018 
End 03/2019
 
Title Analytical models of bending rigidity and shear stiffness for adhesively-bonded sandwich structures 
Description Novel analytical models have been developed for calculating the bending rigidities and shear stiffness of adhesively-bonded sandwich structures with thick or thin face sheets and rigid or flexible cores. The models allow to calculate deflections and strains in complex sandwich structures subjected to transverse loads. The models are formulated in general terms and are therefore applicable to any multi-layer sandwich structure in any area of application. The models have been included in an open-source publication and are therefore publicly available to any engineer interested in the modelling of sandwich structures. These models have also been applied successfully to predict the buckling critical load of adhesively-bonded sandwich structures and the results are now in the process of being included into a scientific publication (which will also include novel data on the surface milling of FRP profiles to optimize adhesion with glass). 
Type Of Material Data analysis technique 
Year Produced 2017 
Provided To Others? No  
Impact The models are novel and constitute a step-change in the capability to predict analytically the response of complex sandwich structures, e.g. structures with shear-flexible adhesives and cores. The models are valid for any type of sandwich structure, but in this specific project they have been used to support and optimise the design of novel adhesive-bonded GFRP-glass sandwich units for building facades. The methodology developed in these models can be applied not only to sandwich structures but also to other structural typologies in the building and bridge construction sector, e.g. frame systems and box-girders. 
URL http://www.sciencedirect.com/science/article/pii/S0263822316314507
 
Description Collaboration with AGC Interpane 
Organisation Interpane Glas Industrie AG
Country Germany 
Sector Private 
PI Contribution Collaboration with world leading glass processor. Exchange of data and information on glass manufacturing and glazing unit manufacturing processes.
Collaborator Contribution Shaoring of data and information on glass manufacturing and glazing unit manufacturing processes. In-kind contributions (materials) for further research.
Impact Industrial partner on two research proposals related to FRP-Glass composites
Start Year 2015
 
Description Collaboration with FRP manufacturer Fiberline 
Organisation Fiberline
Country Denmark 
Sector Private 
PI Contribution Shared data on FRP-Glass test results
Collaborator Contribution FRP materials and technical support
Impact Fiberline are supporting the new research proposal in FRP-Glass Structures
Start Year 2015
 
Description Collaboration with Prof Gary Crichlow at the Materials Department at the Loughborough University on the characterisation and development of novel bonding methods for FRP components in the FRP-Glass composite structures. The main outcome of the collaboration is a new EPSRC proposal that will be submitted shortly. 
Organisation Loughborough University
Country United Kingdom 
Sector Academic/University 
PI Contribution 1. We have shared our insights on FRP-Glass composites structures from the current grant 2. We have provided expertise in structural and building engineers 3. We are coordinating the write-up and submission of a new research proposal in which Nottingham are a partner
Collaborator Contribution Prof Gary Critchlow (Loughborough) has provided in depth knowledge at interface / melcualr level as follows : 1. Surface engineering for optimal adhesion 2. Modification to adhesives by incorporation of micro and nano fillers to improve properties 3. Anti-adhesion / disbonding techniques
Impact new EPSRC proposal (to be submitted shortly)
Start Year 2016
 
Description Collaboration with Prof Nick Warrior and Dr Lee Harper at the Composites Research Group at the University of Nottingham on novel methods of manufacture for FRP components in the FRP-Glass composite structures. The main outcome of the collaboration is a new EPSRC proposal that will be submitted shortly. 
Organisation University of Nottingham
Department School of Biosciences
Country United Kingdom 
Sector Academic/University 
PI Contribution 1. We have shared our insights on FRP-Glass composites structures from the current grant 2. We have provided expertise in structural and building engineers 3. We are coordinating the write-up and submission of a new research proposal in which Nottingham are a partner
Collaborator Contribution Nottingham provided expertise on novel methods of manufacturing FRP (chopped stand / discontinous fibre composites ) that is essential for producing engineering the FRP components in FRP-Glass structures. The techniques pioneered at Nottingham have the the added benefit of lower material waste and higher deposition rates.
Impact new EPSRC standard proposal (to be submitted shortly)
Start Year 2016
 
Description Collaboration with adhesive manufacturer Dow Corning 
Organisation Dow Corning
Country United States 
Sector Private 
PI Contribution Characteristaion of silicone-based adhesives for high performance FRP-Glass applications
Collaborator Contribution Adhesive technology
Impact Dow Corning are supporting follow-on research on FRP-Glass composites within our research group.
Start Year 2016
 
Description Collaboration with adhesive manufacturer Kommerling 
Organisation Kommerling Gmbh
Country Germany 
Sector Private 
PI Contribution Characterisation of high performance adhesive for facade applications
Collaborator Contribution Polymer adhesive chemistry
Impact Kommerling is supporting two research proposals on FRP-Glass composites and is part-funding a PhD on novel liquid composite connections for glass.
Start Year 2015
 
Description Collaboration with engineering consultant: Arup 
Organisation Arup Group
Country United Kingdom 
Sector Private 
PI Contribution Sharing test data on FRP-glass composites
Collaborator Contribution Knowledge and expertise on real-world facade engineering
Impact Arup are supporting two follow-up new proposals on FRP-Glass composites.
Start Year 2015
 
Description Exhibited prototype and public engagement talk at Ecobuild 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact We were invited and accepted to exhibit prototypes of our research at Ecobuild 2017 and to provid a series of talks on our research at the BRE Academy within the Ecobuild Fair. These sparked several questions and interest. The item that attracted most attention was a prop of the cold bent glass in which the audience could interact with the prop and bend the ultra-strong, very thin glass in real time.
Year(s) Of Engagement Activity 2017
URL https://www.youtube.com/watch?v=nfRSdi2jplY&authuser=0
 
Description Industry Engagement Symposium / Workshop at the University of Cambridge 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact 80 people from industry and other research centres attended the Engineered Skins Symposium organised by my Glass & Facade Technology Research Team at the University of Cambridge on 9th September 2015. The future plans for our research activities on FRP-Glass composite structures were presented. This triggered interest from and discussions with several industrial partners on the day as well as and follow-up meetings in the UK, Switzerland and Germany.
Year(s) Of Engagement Activity 2015,2016,2017
URL http://www.gft.eng.cam.ac.uk/news/great-attendance-to-the-gft-symposium-engineered-skins-2015