becomes more gradual, corresponding to the shift of the B-to-QB and D1-to-D2 transition in Fig. \[fig:PhaseDiagram\]. We can understand these effects by pointing out that both weak and strong bonds are introduced due to the spread in sacrificial bond strength. For $\Delta\alpha<0$, $\phi_{f}$ is increased by the disorder due to the presence of weak springs that break before brittle failure occurs. Similarly, for $\Delta\alpha>0$, $\phi_{f}$ decreases due to disorder that introduces bonds that are too strong to break before the matrix fails.

According to the prediction for the MS model in equation \[dist2\] we can collapse all this data on one master curve for all values of $\lambda_S$, $\mu_M/\mu_S$ and $\delta\lambda$, if we consider the rescaled distance to the BDT: $\Delta\tilde{\alpha}$. Indeed we obtain a good collapse for $\phi_{f}$, as shown in Fig. \[fig:BrokenBondRescaling\](b). However, in the brittle regime $\phi_f$ is significantly higher than the prediction of the MS model (dashed line). This could be an indication that the load sharing via the network enhances the failure of sacrificial bonds, however we can not exclude that the discrepancy is due to a finite size effect.

### \[sec:stressConc\] Stress concentration in the spring network model

![image](figure7.eps)

In the MS model it 