Development of a nondestructive impulse device and damage model for unreinforced concrete

Unconstrained compression waves were measured using a newly developed,nondestructive,short impulse excitation device developed for long-term structural health monitoring. the measurements,using this innovative device,were used to determine the variation in the first longitudinal modal frequency as a function of loading magnitude and loading cycles to failure of various concrete mixes. longitudinal frequency and cumulative energy variations were found to be a function of concrete compressive strength. these results imply that higher-strength concrete more easily absorbs energy and restricts the growth of microcracks. based on the results,a new damage model is proposed that was shown to correlate with measured values to within 7%. this proposed model was found to have a closer correlation than miner's hypothesis and damage index models from other reviewed research. © 2012 shane d. boone et al.