Predicting the crushing behavior of pebbles: Theoretical model and experiment verification

Abstract

In this paper, a theoretical model is established to describe pebble-crushing behavior, and the fractal theory was introduced to describe the relationship between original particles and fractures. Considering the size effect and random variation of crushing strength, the Weibull theory was used to characterize the strength variation, and the correlation between the Weibull modulus and fractal dimension was derived. The impact test was performed to verify the established theoretical model’s validity. Results showed that the theoretical model was verified to be valid for crushing behavior description, and the slope of the fitted straight line could be used to calculate the fractal dimension, which is the most critical parameter in fractal theory and could describe the extent of crushing in the pebble bed. The crushing behavior of pebble beds under impact loading was also studied, and test results identified limited evidence of fractal dimension limitation as the impact times increased. The crushing degree could not increase by only increasing the impact times. The extent of crushing had a limitation at a certain drop height. The evolution rate of crushing behavior negatively correlated with total impact energy, and the extent of crushing changed more drastically in a single-layer bed. The established theoretical model and findings presented in this paper add to our understanding of granular material physics, especially the mechanism of particle crushing behavior in a packed bed for fusion blankets.