Dynamic fracture in DCB specimen loaded by end moments

Dynamic fracture depends on a delicate interplay of the dynamic Energy Release Rate (ERR) G d which is the static value G s as reduced by inertia terms depending on crack speed and sometimes acceleration, and the dynamic toughness Γ d which generally varies with crack speed. We review some basic results on Double Cantilever Beam specimen, and make a simple analysis of a DCB under remote bending loads applied slowly. We comment that smooth propagation ensues here contrary to the case discussed in the literature where the loading the end by a constant displacement rate, a very complex non-linearly oscillating velocity results, possibly leading to crack arrest (stick–slip) and which is only partly captured by present models, making difficult the determination of the dynamic toughness. • Dynamic fracture interplay of the dynamic Energy Release Rate (ERR) and dynamic toughness. • Analysis of a DCB under remote bending loads applied slowly. • Smooth transient propagation ensues. • The model a simple illustration of transient dynamic fracture.