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.