of the network by applying an extensional strain $\epsilon$ along the y-axis in small steps of 0.1% strain. We consider quasi-static loading and assume that the networks remain in mechanical equilibrium at each step, i.e. it settles in its minimum energy state. Therefore, after every step, the total energy of the network is minimized by displacing the nodes using the FIRE algorithm [@Bitzek2006] with a tolerance of $F_{rms}\leq1\cdot10^{-5}$. Here, $F_{rms}$ is the maximum root mean squared force allowed in the system [@Bitzek2006]. To simulate failure, we break all bonds which exceed their failure threshold $\lambda_i$ consecutively. After the failure of every single bond the energy of the system is minimized. Once all overstretched bonds are broken, the next strain step is determined according to the bond that is closest to its failure threshold with a minimum step size of 0.001% strain.

For every strain in the simulations the virial stress is calculated from the forces exerted by the springs on the nodes. As the system is elongated along the $y$-direction, we consider the $yy$-component of the virial tensor as a measure for the stress $\sigma$. We define the softening strain $\epsilon_{soft}$ as the strain where the stiffness drops below the 