Toward local identification of cohesive zone models using digital image correlation

Abstract

In recent years, cohesive-zone models have been formulated and used to numerically simulate the fracture of solid materials. Cohesive-zone models presented in the literature involve a 'jump' in the displacement field describing crack onset within a predefined interface network corresponding to interfaces between elements of the finite element (FE) mesh. The introduction of a virtual displacement jump is convenient to numerically manage micro-crack or void initiation, growth and coalescence. Until now, the forms of interface laws were mainly chosen semi-empirically in connection with the overall responses of specimens when subjected to standard loadings. In this study, a cohesive-zone model identification method is proposed based on the local material behavior derived from kinematical measurements obtained by digital image correlation (DIC). A series of tensile loadings were performed for several damageable elastic-plastic materials on standard tensile specimens. Kinematical data analysis enabled early detection and tracking of the zone where the crack will finally occur. The results of this study highlight the

Analysis of a castable refractory using the wedge splitting test and cohesive zone model

“…Elastic and cohesive properties for concrete materials were identified with the Boundary Element Method coupled with DIC measurements [35]. Failure in metals was modeled with a CZM, which was calibrated with DIC data [36]. Micrometer-scale mechanisms in PMMA could be related to a traction-separation law using images taken close to the crack tip [37].…”

Simultaneous Assessment of Mechanical Properties and Boundary Conditions Based on Digital Image Correlation

“…Recent contributions range from civil engineering [5][6][7][8] to high temperature tests on metal alloys and ceramics for aggressive environments [9,10]. In particular, the availability of full-field data allows one to monitor during non trivial tests small regions over the specimen surface, in which the phenomenon of interest turns out to be predominant (see also [11][12][13][14]). Virtual tests on a small sub-domain can thus be performed by assigning local boundary conditions, which integrate or even supersede the overall ones prescribed to the whole tested sample (typically, the reaction force).…”

Measurement of interface cohesive stresses and strains evolutions with combined mixed mode crack propagation test and Backface Strain Monitoring measurements

“…Additionally, specific virtual field identification techniques have been implemented to monitor the damage evolution in the process zone facing the crack tip and elastic modes I and II singular fields at the same time (Réthoré and Estevez, 2013;Mathieu et al, 2013). Now some efforts are engaged for direct measurement of interface separation without any assumption on the shape of the stresses versus displacement discontinuity evolution (Richefeu et al, 2012).…”