Does shear deformability influence the mode II delamination of laminated beams?

Laminated beams affected by interlaminar cracks can be schematised as assemblages of sublaminates, modelled according to some appropriate beam theory. Shear deformability is neglected by the Euler-Bernoulli beam theory, but is taken into account at first order by the Timoshenko beam theory and at higher orders by more refined theories. As well, the connection between the sublaminates can be described by models of growing complexity, ranging from rigid to deformable (elastic or inelastic) interfaces. Consistent with the adopted model, the energy release rate associated to delamination growth can be determined and decomposed into its opening (mode I) and sliding (mode II) contributions. Shear deformability increases the compliance of the structural system and, consequently, may influence the energy release rate. However, the specific influence of shear deformability on the mode II contribution to the energy release rate is not always clear and literature on this point is contradictory. This paper tries to shed light on this controversial issue, by reviewing and critically analysing some of the most relevant studies on this topic. Hence, the circumstances and the ways in which shear deformability may (or may not) influence mode II fracture of delaminated beams should be clarified.