A cohesive model based fragmentation analysis: effects of strain rate and initial defects distribution

A one-dimensional fragmentation analysis that incorporates elastic wave propagation and a cohesive failure process is presented. An irreversible cohesive law models the internal crack nucleation and opening process, and the elastodynamic states of the intact material are calculated using the method of characteristics. Both the average fragment size and the fragment size distribution are obtained. The fragmentation of a model ceramic system is simulated over a wide range of strain rates, and the calculated results are compared to existing theoretical, numerical and experimental results. In the high strain-rate regime, the calculated average fragment size is smaller than that predicted by energy models, but at quasistatic rates the calculated average size is larger than that estimated by such models. The intrinsic mechanisms leading to these deviations are discussed. The fragment size distributions exhibit similarity under all strain-rate range. The effect of the distribution of internal defects on the fragmentation and fragment size distribution is also investigated using this methodology.