Research on concrete cracks based on damage theory and FBG sensing technology

The damage factor, a crucial parameter in assessing the integrity of concrete structures, is determined and validated using the constitutive relationship of concrete and the principle of energy equivalence. The theoretical relationship between Fiber Bragg Grating (FBG) strain sensors and crack monitoring in concrete structures is derived and verified based on the principle of fiber optic sensing. Experimental findings demonstrate that FBG sensors can accurately detect and track crack formation and propagation. The approximate quantitative relationship obtained through theoretical derivation and physical experimentation falls within the acceptable error range for practical engineering applications. Finally, a crack development model for concrete structures is established, and the plastic damage model is employed to derive a dimensionless damage value that can be represented by the measurable crack width.