Advanced Sensors and Novel Concepts for Intelligent and Reliable Processing in Bonded Repairs the SENARIO project

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1 Advanced Sensors and Novel Concepts for Intelligent and Reliable Processing in Bonded Repairs the SENARIO project presented by Mr. David Hernández Rodero SENER & SENARIO Consortium the results of an EC funded research project Framework 6 Aeronautics & Space area

2 Project partners GMI Aero INASCO (coordinator) Laser Zentrum Hannover National Tech. Univ. Athens Kharkiv Aviation Institute Tel Aviv University The SENARIO project Facts and figures Start date: 01/01/2007 Finish date: 30/06/2010 Total effort: 294 man-months Total cost: 2.92 Million Workplan: 9 technical WPs 1 exploitation WP 1 management WP INASMET SENER Israel Aircraft Industries Bombardier Aerospace 7 nations 2 large companies 2 SMEs 1 engineering firm 2 research institutes 3 universities

3 Project Thematic Area The The main limitation of of the the existing technology in in bonding repair of of aerospace structures is is the the inability of of the the repair control systems to to assess the the actual material state and and integrate the the available tools (simulations, measurements, experience and and knowledge) into into an an intelligent material-based control system. To To circumvent these limitations, the the SENARIO project proposes the the development of of a revolutionary sensing systems linked to to intelligent process control equipment and and reliable methodologies of of aerostructures component maintenance.

4 Technical Solution The proposed system consists of: of: portable curing process console with blanket mounted dielectric sensors wireless non-intrusive dielectric sensors for for monitoring adhesive cure reliable laser technology for for increased automation and bonding performance thermo-mechanical simulation and monitoring set-up intelligent multi-zone process guidance system for for the the repair control unit for for co-curing technique for for bonded repairs with reliability, controlled quality and certification potential

5 Fields of activities Hot bonder + process monitoring: SENARIO technology allows the optimal and safe processing of adhesive patch where thermomechanical modelling and simulation tools support complex (multi-zone) controllable repair processes dielectric sensors nano-scale + CURE MONITORING = HOT BONDER PROCESS CONTROL Heater 1 T/C(1) Heater 2 T/C(2) T/C(n) Heater n HOT BONDER CRACKED PART SENSORS + = IN BLANKET INTELLIGENT MULTI-ZONE REPAIR CENTRE

6 SENARIO technology development [1] Development of adhesive sensing system Monitoring cure of patch and adhesive film for repair process optimisation Sensors fabricated for repair process monitoring in metal plate sensing mat embedded / bondline Sensor type NiP on ceramic NiP on ceramic Cu on Kapton film Spacing /channel 100μm / 100μm 100μm / 100μm 80μm / 80μm Structure Air capacitance (pf) Feature durable, high T durable, high T disposable, low cost

7 SENARIO technology development [2] Development of portable cure processing system Integration of hot bonder to monitoring system (concept, hardware, software, applications) Experimental set-up at NTUA laboratory

8 SENARIO technology development [3] Development of portable cure processing system (continued) Integration of sensors in a special mat for monitoring cure of patch during repair process 2 sensors embedded in the sensing mat power wire T/C perforated sheet 1 glass fibre breather heating blanket sensing mat 2 M20 pre-preg aluminium substrate vacuum bag power wire T/C control T/C vacuum bag

9 SENARIO technology development [4] Thermomechanical process monitoring and correlation of sensing Interaction and correlation between dielectric and optical sensing in repair processes Determination of the point where stresses start to build up

10 SENARIO technology development [5] Development of laser technology for adhesive repair Application of laser ablation/processing for altering or improving surface characteristics of composite materials towards bonding optimisation Selective removal of the cured composite matrix Laser Pre- Treatment 3D-Ablation of the cured composite material Deployed UV laser source

11 SENARIO technology development [6] Development of adhesive sensing system Monitoring cure of patch and adhesive film for repair process optimisation Lay-up for repair of composite materials Imaginary Impedance maximum Sensing mat (grey) for monitoring patch cure log [Z''max(Ohm)] sensor 1 T/C Temperature Dielectric sensing [ion viscosity] (blue line) of thermoset patch cure Flat sensor for monitoring adhesive film cure Repair set-up in the instrumented autoclave (Shorts) log [Z''max(Ohm)] Time (min) Imaginary Impedance maximum Time (min) sensor 3 T/C Temperature Dielectric sensing [ion viscosity] (blue line) of adhesive film cure

12 SENARIO technology development [7] Repair process simulation and modelling tools Modelling of cure process for real-time degree of cure measurements (material state monitoring) Simulation tool for integral thermal/mechanical/chemical assessment of thermoset cure in repair processes (where temperature and stress variations are not desired) Integration of parametric cure kinetics and shrinkage models for paste adhesive resin Conversion kinetic model Z"max average values 8 Log Z"max t (min) Determination of the degree of cure in real time through the translation of dielectric signal Temperature [ºC] TEMPERATURE Time [min] Degree of Cure [%] TC T1 T2 T3 T4 T5 several locations of the system T6 T7 T8 T9 80% 70% 60% 50% 40% 30% 20% 10% 0% Prediction of temperature, conversion, strains, etc. at DEGREE OF CURE Time [min] TC T1 T2 T3 T4 T5 T6 T7 T8 T9

13 SENARIO technology benefits and risks Benefits: All these can lead to optimised and improved repair processing, enhanced understanding of the material processes in adhesive bonding (patch and adhesive resin cure), shorter repair cycles and fail-safe procedures. Impact: The application potential is not only limited to aerospace structures. The experience from this project is of great interest also for other industrial innovations as in repair processes of naval and construction structural composites with modelling and sensing capability or even of compacted structures in space, and self-healing surfaces and coatings. Risks: There is not clear risk assessment in the use of embedded thin films at the bondline for the monitoring of adhesive cure during bonding. The sensor size and the cost of sensor wireless communication may become an issue for the industrialisation of the novel technique as cost reduction is a strong driver in the transport sector. Recommendation: Multi-disciplinary research groups offer the potential for targeted technological development and fast knowledge transfer of advanced processing and control to several industrial sectors. These activities should be encouraged and actively supported.

14 Many thanks (from the SENARIO Consortium) to the organisers for allowing SENARIO output to be disseminated to the AeroDays forum For further technical matters and follow-up actions please contact INASCO Hellas