HARVEST kicked off by setting the pathway for two demonstrator parts, a planar leading edge, and a tubular structure. For both demonstrators the 3R epoxy resin provided by CID and TEG-enabled laminae were used.
Initially a dedicated Roll to Roll (R2R) line was built by FOM (Fig. 1). In parallel, UOI and NCYL developed TE enabled nanoparticle inks. CID nanomodified the 3R for increased thermal conductivity. Coated carbon and glass fibres were assessed for TEG-efficiency at tow and fabric level and interfacial properties.
3R, modified with carbon black 3R, hierarchical 3R CF prepregs, and glass fibre (GF)/3R prepregs were manufactured (Fig. 2) and evaluated for quality, tackiness, resin content, resin flow, gel-time and chemical reactivity. Laminates were made by UoI (hot press) and AIR (autoclave curing) and evaluated by IVW for thermal conductivity.
The multi-stage process from raw materials to 3R based composite laminates with their multifunctionality was evaluated at Lab-Scale and Full-Scale (Fig. 3). The quality control included IR thermography, phased array ultrasound, optical microscopy and computed tomography. Characterization of morphologic, structural, functional properties and durability of multi-ply laminates under mechanical & environmental fatigue provided feedback for material- and process optimization. Standardized, established methods, as well as specifically adapted methods were applied and captured the full application potential of the TEG composites.
UoI studied the TE efficiency of specific geometries of p-type and n-type thermoelectric elements and developed through numerous experiments TEG devices printed onto GF fabrics. These were evaluated by TELE, who designed, developed, and tested at lab environment an electronic board with ultralow power consumption. This board could be connected both wired and wirelessly with a data logger and a PC with dedicated software.
A thorough testing campaign was carried out by IVW to assess all system functionalities under simulated operational environments. The system ‘s sensitivity to stress and temperature fields was capable of assessing the structural health of the components (Fig. 4).
In parallel, UNIPD in collaboration with UoI developed new analytical models for the TE behaviour of composite laminates. A multiscale analytical model for three material length scales and the coupled field equations of thermoelectricity was formed (Fig. 5). The TE properties for a unidirectional composite lamina were modelled and an analytical solution for the apparent thermal, electric, and TE properties of composite laminates was developed, considering the presence of progressive damage during the in-service life of the composite. All analytical formulations were validated with numerical simulations and experimental results. The heat sources on the aircraft during operation were identified as potential areas for TEG application.
Finally, the two demos (tubular and planar one) with 3R prepregs and integrated TEG devices were manufactured, based on the combined acquired knowledge. Demonstrators were manufactured by SON, AIR and B&T (Fig. 6) and were controlled for quality using NDT. The demonstrators were instrumented for testing both at lab scale and simulated operational environment (Fig. 7 and Fig. 8) to increase the TRL. SON, UOI & B&T performed various tests and established the efficient power generation to enable the wireless SHM system developed by TELE. Impact tests were performed on representative coupons and the remarkable repairability of the 3R resin was demonstrated.
A LCA and LCC evaluation was performed at both the composite and the demonstrator level and highlighted that the TE and 3R functionalities are not the main contributors with respect to the current commercial solution while a cost reduction of the electronics is essential.
An evaluation of the standardisation landscape and the possible gaps and opportunities for the formulation of new standards was also performed.
Significant results were publicized via the dissemination, communication, and exploitation strategy. Developed communication tools included the website and the social media (Facebook, Twitter, LinkedIn). Effective management of intellectual property rights and a data management plan was established from the early stages of HARVEST. Data associated with scientific publications in peer reviewed journals were made publicly available at the Zenodo repository. Open access deliverables are available on the project website and on the HARVEST webpage at cordis. The project partners participated in conferences, exhibitions and fairs such as ECCM19, AIAS 2020/2021, DEFEA WEXFLEX and ImagineNano.
A plan for exploitation and dissemination was developed for the HARVEST foreground. Leading industries have already expressed their interest in the HARVEST technologies.
A continuous risk assessment process was implemented throughout the project which successfully identified all possible risks and proposed suitable mitigation.
