Model and experimental studies on the effects of load characteristics and polyurethane densities on fatigue damage of rigid polyurethane grouting materials

Abstract

This work aims to theoretically and experimentally investigate the fatigue damage evolution characteristics for rigid polyurethane grouting materials (RPGM). From the theoretical perspective, based on the integral method and classic Chaboche damage evolution model, a theoretical fatigue damage model considering load characteristics (load speed and magnitude) was established. From the experimental perspective, based on the three-point bending experimental fitting, the effects of polyurethane densities on fatigue damage characteristics were considered. In this case, the damage evolution model of semi-empirical and semi-theoretical for RPGM was established. The results show that the fatigue life of RPGM decreases with the increase of load magnitude and polyurethane density but increases with the increase of load speed. On the contrary, the fatigue damage of RPGM increases with the increase of load magnitude and polyurethane density but decreases with the increase of load speed. In addition, the mean relative error between predicted values and experimental results is less than 10 %. At last, the sensitivity analysis shows that the influences of density, load magnitude, and load speed on fatigue life decrease in turn. The damage evolution model established in this work can well predict the damage behavior of RPGM in the entire life cycle. It also can provide good theoretical guidance for the design of rehabilitation and reinforcement engineering.