In implicit Finite Element (FE) codes, decohesion (or interface or cohesive) elements have been successfully used to simulate standard delamination toughness tests (Double Cantilever Beam (DCB), Mixed-Mode Bending (MMB) and End Notch Flexure  (de Moura, 2000; Camanho, 2002; Mi, 1996; Allix, 1999; Ortiz, 1999; Camanho, 2003); debonding of skin/stiffener specimens(Camanho, 2002), overlap tests (Mi, 1998), compression after impact (CAI) of composite plates (de Moura, 2000, Qiu 2001) and crush of composite tubes (Pinho, 2004).

In explicit analyses, nonlinear springs have been used to model the interfaces in layered composites (Wisnom, 1996). Some work using a cohesive zone approach is presented in Refs. (Johnson, 2001; Pickett, 2002), in which the applications include MMB specimens and the impact with penetration of a steel ball in a composite plate. In another work, Borg et al. (Borg, 2001) used a discrete cohesive zone approach to model delamination. Coincident nodes were tied together with a penalty formulation before delamination onset. During damage propagation, the nodal forces were reduced to zero as the amount of dissipated work approached a value corresponding to the fracture energy, which was obtained from the energy release rate using the respective nodal area. The model was then modified to use a damage formulation (Borg, 2002), and was finally implemented within a contact algorithm (Borg, 2004; Borg, 2004b).

In implicit analyses, this author has worked with and developed further a decohesion element for the software Abaqus. The decohesion element had counted with previous development work from J P Goncalves, M F Moura, P P Camanho and C G Dávila. A publication in an international journal resulting from this work can be found here. Alternatively, the interested reader can find more details in Silvestre Pinho's Master thesis (in Portuguese).

In explicit analyses, this author has coded a decohesion element in LS-Dyna. The decohesion element is 3D, has mixed-mode capabilities and the user can choose from three different constitutive laws: (i) bilinear, (ii) 3rd order polynomial and (iii) combination of linear and curvilinear segments. A journal publication resulting from this work can be found here.

Any researcher whishing to establish some form of collaboration on modelling delamination, any company whishing to use the modelling capabilities developed, and any prospective research student whishing to be supervised in this area, are encouraged to send an email to Silvestre Pinho. Prospective students should also consult the respective section of this site, by clicking here. Contact information can be found here.