Newsletters & News Releases

2015

Real-life challenges provided by the industrial partners confirm the significance of the ComBoNDT research and the necessity of introducing quality assurance concepts for adhesive bonding. These challenges cover both areas of Manufacturing and Repair and are examined as test-cases. The various materials, processes and parameters related to these applications (e.g. CFRP materials, types of adhesives used, surface preparations, etc.) are thoroughly examined and a list of specifications was developed towards the development of test coupons. The first samples are already produced and, following a series of preparation processes, these are now distributed to the respective partners for conducting their experiments. Sample preparation include activities such as surface pre-treatment, cutting of CFRP samples, surface conditioning, bonding of samples, as well as a series of mechanical tests. Activities regarding the development of ENDT for surface quality assurance have just started and partners are considering the various surface inspection methods to be explored, matured and optimized within ComBoNDT. In a similar way, partners examine the processes to be used for the quality assurance of adhesive bonding. Activities on the validation of ENDT techniques and technology assessment currently cover the examination of Technology Readiness Levels (TRL) 3 and 4 while TRLs 5 and 6 will be examined later in the project.

Link: http://www.easn.net/newsletters/EASN_Newsletter_December_2015.html

ComBoNDT (Quality assurance concepts for adhesive bonding of aircraft composite structures by advanced NDT) is a collaborative project funded under Horizon 2020, aiming at overcoming the difficulties in predicting and assessing the bond quality by using advanced non-destructive testing methods. The project will provide knowledge for certification of adhesive bonding technology as joining technique for load-critical CFRP primary structures. This goal will be pursued by further development and maturation of extended non-destructive testing (ENDT) methods suitable for pre- and post-bond inspection of adherend surfaces and adhesively bonded joints.

Coordinated by Fraunhofer IFAM, ComBoNDT brings together 13 partners from 8 European countries with vast experience in their field, allowing for a seamless course towards achieving the project’s objectives.
Following the successful Kick-off Meeting held in May, 2015 the ComBoNDT project launched its activities, focusing on applying its threefold approach which entails a) reliable and reproducible detection of undefined and/or multiple contaminations on surfaces prior bonding, triggering surface cleaning and activation measures, b) reliable and reproducible detection of poor bond quality, triggering appropriate repair actions and c) improvements in robustness of methods addressing the requirements of in-line inspection in both aircraft manufacturing and MRO environments.

Link: http://www.easn.net/newsletters/EASN_Newsletter_July_2015.html

The integration of innovative lightweight materials like CFRP into multi-material design (MMD) environments in aeronautic applications brings along a paradigm shift in initial design, manufacturing and in maintenance, repair and overhaul (MRO).
Essential cost reductions over the whole aircraft lifecycle demand innovative processes meeting the specific requirements of MMD in general and specifically of CFRP.
The certification of (structural) adhesive bonding marks a key step for full integration of CFRP, as adhesive bonding is the optimum CFRP joining technology. As yet, difficulties in predicting and assessing the bond quality by non-destructive testing limit the certification of adhesive bonding technologies and subsequently their usage in aeronautic applications.
ComBoNDT (Quality assurance concepts for adhesive bonding of aircraft composite structures by extended NDT) aims at overcoming these limitations through the enhanced development and maturation of extended non-destructive testing (ENDT) methods suitable for pre- and post-bond inspection of adhered surfaces and adhesively bonded joints.
The ComBoNDT approach is threefold and includes:
- reliable and reproducible detection of undefined and/or multiple contaminations on surfaces prior bonding, triggering surface cleaning and activation measures
- reliable and reproducible detection of poor bond quality, triggering appropriate repair actions
- improvements in robustness of methods addressing the requirements of in-line inspection in both aircraft manufacturing and MRO environments.
Time savings of up to 70% and cost savings of up to 50% in related production, MRO and retrofit processes are expected from the application of ENDT technologies resulting from ComBoNDT. The project addresses relevant levels of technology and of manufacturing readiness.
ComBoNDT will contribute to the implementation of safe, cost- and time-efficient adhesive bonding technologies and to the reduction of production and MRO costs.
For more information visit the ComBoNDT website (http://combondt.eu/)

Link: https://easn.net/research-projects/

The integration of innovative lightweight materials like CFRP into multi-material design (MMD) environments in aeronautic applications brings along a paradigm shift in initial design, manufacturing and in maintenance, repair and overhaul (MRO). Essential cost reductions over the whole aircraft lifecycle demand innovative processes meeting the specific requirements of MMD in general and specifically of CFRP. The certification of (structural) adhesive bonding marks a key step for full integration of CFRP, as adhesive bonding is the optimum CFRP joining technology. As yet, difficulties in predicting and assessing the bond quality by non-destructive testing limit the certification of adhesive bonding technologies and subsequently their usage in aeronautic applications. ComBoNDT (Quality assurance concepts for adhesive bonding of aircraft composite structures by extended NDT) aims at overcoming these limitations through the enhanced development and maturation of extended non-destructive testing (ENDT) methods suitable for pre- and post-bond inspection of adhered surfaces and adhesively bonded joints. The ComBoNDT approach is threefold and includes:

reliable and reproducible detection of undefined and/or multiple contaminations on surfaces prior bonding, triggering surface cleaning and activation measures
reliable and reproducible detection of poor bond quality, triggering appropriate repair actions
improvements in robustness of methods addressing the requirements of in-line inspection in both aircraft manufacturing and MRO environments.
Time savings of up to 70% and cost savings of up to 50% in related production, MRO and retrofit processes are expected from the application of ENDT technologies resulting from ComBoNDT. The project addresses relevant levels of technology and of manufacturing readiness. ComBoNDT will contribute to the implementation of safe, cost- and time-efficient adhesive bonding technologies and to the reduction of production and MRO costs.

Link: http://easn-tis.com/projects/combondt

2016

The first year of the on-going Horizon 2020 funded project Quality Assurance Concepts for Adhesive Bonding of Aircraft Composite Structures by Advanced NDT (ComBoNDT) was successfully achieved. The achievements and next steps were presented in the ONE-YEAR COMBONDT PROJECT MEETING in Toulouse from 12.05. to 13.05.2016 hosted by the Airbus Group Innovation partner in France. In the first year the CFRP test coupon samples (flat samples) were successfully produced considering a series of single contaminations characterizing typical manufacturing and repair scenarios. The samples were tested via the extended non-destructive testing (ENDT) techniques for surface and bondline quality assurance. The ENDT techniques are explored, matured and optimized showing great capacity of detecting the presence of the single contaminants in both considered scenarios of manufacturing and repair. In the next steps, samples containing multiple contaminations will be produced and tested. In addition, pilot samples on more complex and realistic geometries will be produced and tested via the ENDT techniques, i.e. curved and scarfed samples for the manufacturing and repair scenarios, respectively.

Link: http://www.easn.net/newsletters/EASN_Newsletter_June_2016.html

Reference samples were prepared for the production and repair scenarios, which will be used for comparison against all other respective samples. The contaminated samples for the production scenarios comprised of release agent (RA), fingerprint (FP) and moisture (MO) contaminated samples with three levels of intensity each, whereas the repair scenario examines samples contaminated with de-icer (DI) and fingerprints (FP), thermally degraded (TD) samples and faulty cured (FC) samples. ENDT techniques for surface quality assurance (Laser Induced Breakdown Spectroscopy (LIBS), Optically Stimulated Electron Emission (OSEE), Full Field Vibrometry, Electronic Nose (E-NOSE), Aerosol-Wetting-Test BoNDTinspect, FTIR-Spectroscopy) are being tested, matured and improved by adaptation, against their sensitivity to detect physico-chemical properties of the adhered surfaces caring with multiple contaminations, and on the possibility to quantify the measuring results. Adhesively bonded samples for the cases of faulty curing and thermal degradation contaminants have been characterized by means of conventional ultrasonic NDT testing in order to control the sample quality by checking the absence of defects. They will afterwards be inspected by different methods for NDT of bonded structures (Shock Wave Adhesion Test, Electromechanical Impedance, Linear and Non-linear Ultrasound and Magnetostrictive Sensors). Meanwhile, the first mechanical tests (Mode I and Mode II fracture toughness) were conducted at the reference samples and the samples with faulty curing of the adhesive presented a loss of the bonded joint quality.

Link: http://easn.net/newsletters/EASN_Newsletter_March_2016.html

2017

ComBoNDT is currently in its third year of activities and several important milestones have been achieved so far. In regards to sample preparation, all the samples were investigated via conventional NDT inspection using two different probes and two different settings respectively. Also, all the mechanical testing, namely mode-I, mode-II and centrifuge tests were completed and the experimental results reveal the negative effect of each contamination scenario in the fracture toughness and adhesive strength of the composite bonds. Also, mechanical tests on pilot samples were conducted in order to evaluate the influence of the surface state on the mechanical properties of the scarfed pilot samples. The results showed that the combined contamination with thermal degradation and de-icing fluid has a negative effect on the mechanical performance of the scarfed repair joints, reducing the failure load. Also during this period, the pilot samples were tested via the ENDT techniques and the partners were working in optimizing the techniques to investigate realistic parts as well as to turn the ENDT automated. Some of the employed ENDT such as LIBS (Laser Induced Breakdown Spectroscopy), OSEE (Optically Stimulated Electron Emission) and AWT (Aerosol Wetting Test) were developed to be handled directly by robot. In addition, partners investigated flat coupons with single and mixed contaminations, curved bonded samples with mixed contaminations, and bonded scarf samples with mixed contaminations within this period.

In December 2017 the demonstration will take place at the IFAM premises in Bremen where the following activities will take place: Repair process (scarfing, surface treatment patching, bonding, etc.), Production process (secondary bonding of stringers above skin, autoclave, etc.), WP3 technique demonstration before bonding, and WP4 technique demonstration after bonding.

Currently the project is organizing its M30 Progress Meeting to take place at the Institute of Aviation in Warsaw, Poland on the 29th of September 2017 within the frame of the 7th EASN International Conference on “Innovation in European Aeronautics Research”.

Link: http://www.easn.net/newsletters/issues/easn-newsletter-september-2017

ComBoNDT images

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 636494.

This project is endorsed by the European Aeronautics Science Network - EASN.

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