Fractal analysis of damage detected by acoustic emissions in prestressed reinforced concrete beam under loading

Abstract

For researching the relationship between prestressed reinforced concrete acoustic emissions (AE) signal and its damage evolution information, the paper studies AE signal parameter sequence fractal characteristics for destruction of whole process of prestressed reinforced concrete under different stress level. The research results show that in the process of destruction, AE signal energy parameter sequence has obvious fractal characters at a scale. AE process has different degree of self-similari ty under different loading level,so the mechanical state beam structure can be described by the correlation dimension. It indicated that beam structure has damage when correlation dimension cuts down to a minimum and then reaches to the maximum. This model of the range of the changes reflects the damage degree. It will appear more serious damage when the correlation dimension is in stable state after damage. It gives the theoretical basis and methods for prestressed concrete structure health monitoring and nondestructive testing. This paper starting from the structural health monitoring and nondestructive testing purpose, which apply fractal theory to analysis of acoustic emission phenomenon of concrete structure, and make the acoustic emission characteristic parameters of correlation dimension model. The experiment can prove that the existence of prestressed reinforced concrete AE phenomenon of fractal characteristics,and obtain he law of fractal characteristics correlation dimension change in the process of prestressed reinforced concrete damage. We can link the acoustic emission signal with damage stage of prestressed concrete in order to obtain more nature information of reinforced concrete damage. All that can provide the theory basis of accurately for concrete structure health monitoring and nondestructive testing.