BOPACS

What is BOPACS?

BOLTLESS ASSEMBLING OF PRIMARY AEROSPACE COMPOSITE STRUCTURES

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.

Project

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.

Papers

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)

Partners

Coordinator: NLR

List of participants:

Logo / website	Participant organisation name	Country
	Netherlands Aerospace Centre – NLR	NLD
	Cenaero ASBL, Centre de recherches en Aéronautique	BEL
	Université Catholique de Louvain, Institute of Mechanics, Materials, and Civil Engineering	BEL
	Société Anonyme Belge de Constructions Aéronautiques SABCA S.A.	BEL
	Výzkumný a Zkušební Letecký Ústav, A. S.	CZE
	Deutschen Zentrums für Luft- und Raumfahrt	DEU
	Institut für Flugzeugbau, Universität Stuttgart	DEU
	Airbus Defence and Space GmBH	DEU
	Laboratory of Technology & Strength of Materials, University of Patras	GRC
	Zurich university of Applied Science	CHE
	Bombardier Aerospace – Belfast	GBR
	Fraunhofer Institut für Fertigungstechnik und angewandte Materialforschung	DEU
	Airbus Operations GmBH	DEU
	FIDAMC	ESP