Tessellation methods have been applied to characterize second-phase particle fields and the degree of clustering present in AA5754 and AA5182 automotive sheet alloys. A model of damage development within these materials has been developed using a damage percolation approach based on measured particle distributions. The model accepts tessellated particle fields in order to capture the spatial distributions of particles, as well as nearest neighbour and cluster parameter data. The model demonstrates that damage initiates and percolates within particle clusters in a stable fashion for the majority of the deformation history. Macrocracking leading to final failure occurs as a chain reaction with catastrophic void linkage triggered once linkage beyond three or more clusters of voids takes place. A parametric study has been undertaken considering subfields of larger particle fields in order to study the effect of choice of representative volume element (RVE) on ductility predictions.