The simulation models the weakening of timber joints.

: The model shows that central regions of an empire accumulate wealth, while peripheral villages are left in a "mismatch" where they have some wealth but very little protection, leading to a long-lasting cycle of raids and social decline. PubMed Central (PMC) (.gov) Other Notable Simulations

If the siege lasts, cut rations to "Survival" levels to keep your warriors fighting longer.