Heterogeneous Fibre Optic sensor Arrays to Monitor Composite Manufacture (H-FOAM)

The UK composites sector has the potential to grow from £2.3Bn to £12Bn by 2030, driven by demand for light weight, energy efficient structures across sectors including aerospace, automotive, marine and renewable energy. In addition to economic considerations, the growth of composites manufacturing is also key to meeting the Government's Net Zero targets through, for instance, increased deployment of UK manufactured wind turbines.

The UK has world leading research capability in composites manufacturing focussed on design, process innovation, novel and sustainable material combinations and modelling tools. Instrumentation to support this research community, by monitoring composites manufacturing processes, has fallen behind and this will potentially hinder the realisation of the full value of current research activities. Researchers and manufacturers need better data about the complex mechano-thermo-chemical processes which occur during resin infusion and curing in order to improve yield, reduce waste and speed the introduction of new component designs and material combinations.

We have demonstrated that fibre optic sensors, are able to monitor individual key process parameters of resin flow front position and velocity and degree of curing, as well as temperature and strain, in real time at many measurement points. However, to make a useable instrument, where multiple measurands are extracted, it is necessary to use heterogeneous combinations of co-located sensors with appropriate signal processing to disaggregate the desired information. We will adopt combinations of Fibre Bragg Grating sensors to monitor temperature and strain with Long Period Gratings to monitor resin motion and refractive index and hence degree of curing. In order to address the cross sensitivity of these sensors, we will adopt sophisticated signal processing techniques to disaggregate measurements and extract the desired measurands in a form appropriate to users. In addition, sensors need to be encapsulated and connected in a manner which makes them easy to handle and deploy. We will develop packaging solutions and mesh configurations which provide robustness. We will seek to develop this technology into a cost effective instrument which can be used by scientists and engineers, who are not photonics experts, but who seek to gain better understanding of the complex but critical processes which occur during composite manufacture.