On the determination of delamination toughness by using multidirectional DCB specimens

This work covers the problems encountered in correctly determining mode I interlaminar fracture toughness of composite materials. Pure mode I tests were performed on double cantilever beam (DCB) specimens composed by quasi-homogeneous and uncoupled multidirectional (MD) laminates using 16 or 26-ply: [α/−α2/α/−α/α2/−α]sym or anti-sym and [0/α/−α/02/−α/0/α/02/α/−α/0]sym, with α = 0°,15°,30°,45°,90°. A finite element analysis shows that the...