Cohesive zone model and quasibrittle failure of wood: A new light on the adapted specimen geometries for fracture tests

Wood fracture characterization under mode I loading using the three-point-bending test. Experimental investigation of Picea abies L.

“…Therefore, this specimen size is not adequate to perform fracture toughness measurements in this wood species. This behaviour results from the premature confinement of the fracture process zone (FPZ) that is restricted to develop freely in a self-similar way for a given crack extent (Coureau et al 2013). Even if an initial crack length smaller than 35 mm had been considered, the consequent increase of unstable crack propagation would lead to the same problem of FPZ confinement.…”

“…Using this specimen geometry Dourado et al (2008) identified the interaction of the fracture process zone with the specimen boundaries. This phenomenon, also known as FPZ confinement, precludes an accurate determination of fracture toughness in quasi-brittle failure (Coureau et al 2013). The aim of this study is to determine experimentally the adequate specimen size leading to accurate evaluation of fracture toughness in Picea abies L. using the SEN-TPB test.…”

Cohesive zone modeling and calibration for mode I tearing of large ductile plates

“…In this paper, a cohesive zone is used to represent the sequence of failure processes. Similar efforts for both ductile and brittle materials have been undertaken by other authors [2,4,9,17,31]. Simonsen and Törnqvist [18] employed a critical plastic strain criterion to advance the crack tip, demonstrating how the critical strain must depend on element size when calibrated against experiment.…”

On the validation of integrated DIC with tapered double cantilever beam tests

“…Different TDCB specimens were used to perform mode I fracture tests of adhesive bond joints [6,7,8] and, for instance, to study the R-curve behavior in 25 quasi-brittle wood materials [9] taking advantage of the crack growth stability provided by the tapered shape. In many displacement-controlled TDCB experiments, it has been observed that the compliance increases linearly with the crack length.…”