Fig. The load-displacement curve for a single-edge notched specimen for different values of n
5.3.2 Single-edge notched shear test
The boundary conditions are presented in Table 3-III for load applying direction of \(45\). The mesh consists of \(4056\) finite elements and is refined in the expected crack propagation area. Fig.5 shows the crack pattern solution for \(n=2\) and \(n=1.5\).
Fig.6 shows the computed load-displacement curve and variation of the reaction force over the loading history. As is shown, the normal ductile behavior proceeds until the crack initiates. However, the crack propagation is so brutal. The \(n\) value also influence the load carrying capacity of the specimen. The crack starts to propagate at a higher applied displacement as the value of \(n\) decreases, leading to a higher load carrying capacity of the specimen. This numerical example shows that large \(n\) values lead to brittle fracture while small \(n\)values result in ductile fracture. The proposed phase-field model is capable of simulating both brittle fracture and ductile fracture as well as the ductile-brittle transition if \(n\) is set to be a function of field variables such as q parameter.