What is BOPACS?


The small or medium-scale research project BOPACS concentrates on the bonding of primary composite structures in compliance with the EASA airworthiness regulations. Therefore a thorough research is performed into the propagation of cracks into the bondline area and subsequently the development of features that can be implemented to arrest or slow down the propagation of cracks. The project is executed by a team of European industries, institutes and universities.

The project started in September 2013 and has a lead time of 49 months.

The website gives information about the content of the project and the dissemination activities.


BOPACS is set to reduce the weight and costs of primary composite aerospace structures by enabling secondary bonding as joining technology. Until today thin walled composite structures are joined by using a large number of fasteners. Adhesively secondary bonding would considerably contribute to the weight and cost reduction but they can not fulfil the airworthiness requirements up to now. In order to meet airworthiness requirements for secondary bonded structures BOPACS proposes a rigorous road map to certification by developing Means of Comply based on:

  • Thorough research, beyond the state of the art, into the crack growth / disbond extension mechanisms in adhesively bonded joints.
  • Design, analysis, testing and assessment of different categories of crack stopping design features, i.e. features that are capable of preventing cracks or disbonds from growing above a predefined acceptable size, with a joint still capable of carrying the limit load.

This topic is considered as a breakthrough technology. It secures structural integrity of the bond line throughout the entire service life. NDT and process safety are not considered to fill in this gap. Based on aerospace target applications secondary bonded joining methods will be developed that comply with the EASA airworthiness requirements.


Title Author
Fatigue behaviour and damage tolerant design of composite bonded joints for aerospace application T. Kruse, T. Körwien and R. Ruzek
Numerical simulation of fatigue crack growth in the adhesive bondline of hybrid CFRP joints R. Sachse, A.K. Pickett, M. Käß, P. Middendorf
A Hybrid Bondline Concept for Bonded Composite Joints T. Löbel, D. Holzhüter, M. Sinapius, C. Hühne
Experimental investigation of mechanical fasteners regarding their influence on crack growth in adhesively bonded CRFP-joints subjected to fatigue Loading R. Sachse, A.K. Pickett, W. Adebahr, M. Klein, M. Käß, P. Middendorf
Bonding of cfrp primary aerospace structures – crackstopping in composite bonded joints under fatigue T. Kruse, Dr. T. Körwien, S. Heckner and Dr. M. Geistbeck
Mode-I, mode-II and mixed-mode I+II fracture behavior of composite bonded joints: Experimental characterization and numerical simulation I. Floros, K.I. Tserpes, and T. Löbel

Presentations of BOPACS

Event Author
Aerodays, 7th European Aeronautics Days, October 2015 Jan Halm (NLR)
EASN, 2-4 September 2015, Manchester UK Konstantinos Tserpes (UPAT)
3rd International EASN Workshop on Aerostructures, Milan, 9-11 October 2013 Konstantinos Tserpes (UPAT)


Coordinator: NLR

List of participants:

Logo / website Participant organisation name Country
NLR_Logo_50px Netherlands Aerospace Centre – NLR flag-nl NLD
cenaero_logotable20 Cenaero ASBL, Centre de recherches en Aéronautique flag-be BEL
ucl-logotable20 Université Catholique de Louvain,
Institute of Mechanics, Materials, and Civil Engineering
flag-be BEL
sabcatable20 Société Anonyme Belge de Constructions Aéronautiques SABCA S.A. flag-be BEL
vzlu_logotable20 Výzkumný a Zkušební Letecký Ústav, A. S. flag-cz CZE
dlr_logotable20 Deutschen Zentrums für Luft- und Raumfahrt flag-de DEU
ifb_logotable20 Institut für Flugzeugbau, Universität Stuttgart flag-de DEU
airbus-defence-and-space-logo Airbus Defence and Space GmBH flag-de DEU
UPAT-logo Laboratory of Technology & Strength of Materials, University of Patras flag-gr GRC
zhaw_logotable20 Zurich university of Applied Science flag-ch CHE
bombardier_logotable20 Bombardier Aerospace – Belfast flag-gb GBR
ifam_logotable20 Fraunhofer Institut für Fertigungstechnik und angewandte Materialforschung flag-de DEU
AIRBUS_Group_3D_Blue Airbus Operations GmBH flag-de DEU
fidamc_logotable20 FIDAMC flag-es ESP

Invitation BOPACS End SymposiumBOPACS End Symposium
Was held on September 5 & 6 @ Hamburg


Please feel free to contact us:

Jan Halm
R&D Engineer, Netherlands Aerospace Centre NLR
Phone: +31 88 511 4204

BOPACS Disclaimer