Abstract: In the light of the dynamical analysis of microcrack coalescence, this paperpresents a statistical fractal modeI to describe the damage evolution of spailation. Themodel demonstrates that the mechanisnl of fractal surfaces formed in spallatioii is cioselyrelated to the dynainic processes of the cascade coalescence of lnicrocracks.A unimodalrelation between the fractal dimension and the coalescence threshold based on the modelcan qualitatively explain the challenging observation of fractal dimension versus t...