Non-conventional approaches to measure 
the delamination fracture toughness:
 the example of the Double Drum Peel test

Federica Daghia (1) , Christophe Cluzel (1) , Benoit Courtemanche (2)

1 LMT - Laboratoire de mécanique et technologie
2 CETIM - CEntre Technique des Industries Mécaniques

Cantilever Beam, End Notched Flexure, ...) involve flat, unidirectional specimens with an initial delamination within the mid-plane, which enable one to easily control the mode mixity at the crack tip. Many real-life structures, however, such as non-symmetric stacking sequences, sandwich panels or curved structures, do not correspond to this description. For these kinds of specimens, alternative testing configurations are required in order to characterize the delamination fracture toughness while remaining close to the geometry and manufacturing conditions of the real part. Different examples of non-conventional testing approaches, derived from the adhesives’ community and already investigated by the authors [1,2], are illustrated in this work, with a particular focus on the new Double Drum Peel (DDP) test configuration. The DDP was originally conceived by the Cetim in order to investigate the link between the manufacturing parameters and the quality of the interface thermoplastic matrix composites manufactured by Laser Assisted Tape Placement (LATP), and it is here reinterpreted as a delamination test. In all of the considered approaches, a global energy balance enables one to quantify the energy associated to interface delamination, eventually accounting for energy losses in other portions of the structure. As pure-mode loading conditions cannot be applied easily to a general test configuration, the loading conditions seen by the propagating crack need to be characterized. Some DDP test on thermoset and thermoplastic matrix composites are performed in order to assess the potential of this testing method. A more physics-based link between the loading conditions seen by the propagating crack and the measured fracture toughness constitutes a perspective of this work. References: [1] F. Daghia and C. Cluzel, The Climbing Drum Peel (CDP) test: an alternative to the Double Cantilever Beam (DCB) for the determination of fracture toughness of monolithic laminates, Composites: Part A 78(2015):70-83. [2] F. Daghia, C. Cluzel, L. Hébrard, F. Churlaud, B. Courtemanche, The Double Drum Peel (DDP) test: a new concept to evaluate the delamination fracture toughness of cylindrical laminates, Composites: Part A 113(2018):83-94.

Mots clés: delamination; non-standard specimens; Double Drum Peel test

Domaines: Mécanique des matériaux [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Mécanique des structures [physics.class-ph]

Federica Daghia, Christophe Cluzel, Benoit Courtemanche. Non-conventional approaches to measure 
the delamination fracture toughness:
 the example of the Double Drum Peel test. Cancelled - ECCM19 - 19th European Conference on Composite Materials, Jun 2020, Nantes, France. ⟨hal-02386938⟩