An impulse-based model for impact between two concrete blocks

Drop-weight tests were conducted on 10 pairs of reinforced concrete cubic blocks with a side length of 250 mm to investigate their motion states during the impact process. The collision type was face-to-face collinear impact which was primary collision type in structural collapse due to natural or man-made hazards. Incident velocity and reinforcement ratio were two test variables and the block acceleration histories were measured. A model based on the smooth particle hydrodynamics (SPH) method was developed, verified, and used for parametric studies. Experimental results found that impulses increased almost linearly with the increase in incident velocities of less than 13 m/s. However, numerical results indicated that their correlation became nonlinear when incident velocities exceeded 30 m/s. The impulses also increased with the increase in mass ratios and decreased almost linearly with the increase in initial impact angles based on numerical studies. These new findings differ from traditional rigid body impact theory. Moreover, parametric studies revealed that the impulses increased linearly with the increase in block masses and concrete compressive strengths. Reinforcement ratios had no effect on the impulse and acceleration history of colliding blocks based on experimental and numerical studies. Finally, an impulse-based model was introduced to predict motion state after impact and had good correlation with the experimental data.