Macroscopic networks of thermal conduction: Failure tolerance and switching processes

The world is so wonderful and colorful thanks to the analytic discontinuities and singularities of phase transitions. Here we propose a class of macroscopic networks of thermal conduction that combine regular networks with macroscopic thermally conductive systems. We find that their phase transition phenomena (variation tendency) cannot be explained simultaneously by existing theories of networks, percolation or effective media. We report the bond-free property of these networks and the associated three switching processes caused by the geometric property of bonds, and we reveal the effect of single-point connection. Also, we propose some potential applications including thermal diodes. Our results are confirmed by finite-element method simulation and experiment. This work offers different insights into the theories of networks, percolation and effective media. It also provides a different method to design thermal metamaterials and manipulate thermal conductivities.