Measurement of critical energy restitution rate
Fracture Mechanics of Composite : Delamination and Cracking

To determine the critical energy restitution rate of a crack G _c , we need to design a test that will cause it to propagate, and measure the energy dissipated by this propagation. Let's imagine such a test with a force F applied at one point on the structure and the resulting displacement u at the same point. To calculate the work applied to the structure, we need to ensure that only the work of this force F is supplied to the structure, which is generally the case, as there are many other forces applied at the level of the embedding conditions, but as at the same time the displacements are zero, the corresponding work will also be zero. The work of external forces, W _ext ...