If the crack is growing straight, the energy release rate can be decomposed as a sum of 3 terms G i associated with the energy in each 3 modes. As a result, the Nodal Release method (NR) can be used to determine G i from FEA results. The energy release rate is calculated at the nodes of the finite element mesh for the crack at an initial length and extended by a small distance Δ Δ a . First, we calculate the displacement variation at the node of interest Δ Δ u → → = u → → ( t + 1 ) − − u → → ( t ) (before and after the crack tip node is released). Secondly, we keep track of the nodal force F → → outputted by FEA. Finally, we can find each components of G using the following formulas: