HVD-Based Damage Detection for Prefabricated Composite Wallboard Connectors

According to the experimental results, the relative curvature value of HVD marginal spectral entropy can be calculated and the conclusion can be drawn :
( 1 ) Under the single damage condition, the relative curvature of the HVD marginal spectrum entropy at the damaged connector shows a significant change, and its value reaches the peak level. The research shows that when the position of the damaged connector remains unchanged, with the gradual aggravation of the damage degree, the relative curvature change range of the marginal spectral entropy of the connector is further expanded, thus significantly improving the identifiability of the damage position.
( 2 ) For multiple damages, the relative curvature value of marginal spectral entropy can determine the location of the damaged connector, but the judgment of the degree of damage is insufficient.
Based on the test results, the entropy difference of HVD power spectral density can be calculated and the following conclusions can be drawn :
( 1 ) For single damage, the difference of HVD power spectral density entropy at the damaged connector changes obviously, and the value is the maximum. When the location of the damaged connector is the same, with the gradual increase of the degree of damage, the change of the power spectral density entropy difference of the damaged connector is more significant, and the recognition of the damage location is improved.
( 2 ) For multiple damages, the power spectral density entropy difference can not only determine the location of the damaged connectors, but also distinguish the damage degree of different damaged connectors.
The analysis based on the relative curvature of the marginal spectral entropy shows that the method can accurately identify the damage location in the single damage condition, and the curvature difference increases significantly with the increase of the damage degree, but it is difficult to distinguish the damage degree difference under the multi-damage condition. In contrast, the power spectral density entropy difference method is not only sensitive to single damage location, but also can effectively distinguish the damage degree of different connectors in multiple damage scenarios, showing higher comprehensive performance.