Euro study seeks optimally damage-tolerant infrastructure composites

It is a familiar scenario: An old concrete bridge with narrow lanes has to be widened to accommodate more traffic pedestrians and meet new standards. It then turns out that the bridge cannot support the weight of a wider concrete superstructure without further support, resulting in the costly reinforcement of bridge pillars or piers, or, a new bridge altogether.

Under the direction of the European Union Horizon 2020, groups from five different countries are now conducting materials research into enabling the production of deck extensions and other bridge elements made of fiber-reinforced plastic, says the project leader Jens Kjær Jørgensen of SINTEF Industry (Trondheim, Norway). The research project, which began in January of 2018 and will run through December 2021, is called DACOMAT, for Damage Controlled Composite Materials.

The objective of DACOMAT is to develop more damage-tolerant and damage-predictable, low-cost composite materials, in particular those used in large load-carrying constructions like bridges, buildings, wind turbine blades and offshore structures. The developed materials and condition monitoring solutions will provide a high tolerance for manufacturing imperfections and high capacity to sustain damages. This will enable large composite structures to be manufactured and maintained at low cost. Project outcomes include the development of guidelines and modeling tools for reliable design of critical load carrying composite structures; guidelines for materials qualification; structural health monitoring (SHM) and damage assessment solutions; and life cycle analysis (LCA) methodology for large composite constructions.

The project is being coordinated by SINTEF, says Jørgensen. Participating companies include Polynt Composites (Carpentersville, IL, US), Hexcel (Stamford, CT, US), Carbures (Cadiz, Spain), 3B Fiberglass (Battice, Belgium), LM Windpower (Lunderskov, Denmark) and DNV GL (Oslo, Norway), in addition to several universities. The participants will work together to ensure that any development of fractures has minimal likelihood of compromising the strength of composite bridge elements and wind turbine blades. Specifically, the project is aiming to produce materials whose properties will make it even more difficult than in existing alternatives for fractures to propagate. “The objective is to develop composites that will give bridges a longer lifetime than conventional structures, while reducing lifespan costs by 30%. In the case of wind turbine blades, the aim is a 30% increase in lifespan and a 50% reduction in costs,” says Jørgensen.

To acquire more knowledge about material properties over time, the project is also aiming to develop technology that will enable the monitoring of fracture development using optical and acoustic sensors. The project's findings will also be applicable to offshore installations and other structures that have to withstand harsh environmental conditions.