## 5 Conclusions  
In this paper, a two-stage damage localization method is proposed to identify the damaged edges and midpoints of damaged structural sealants through the BMC. Based on the numerical and experimental results, the following conclusions can be drawn:  
1. The damaged edges of the structural sealant can be identified by the proposed ACBMC index effectively. A threshold value of 0.85 for the ACBMC of the first mode can identify the damaged edges of the structural sealant. Through numerical calculations and actual experiments, it can be found that the ACBMC index is more sensitive to damage than BMC alone. Additionally, the change in the ACBMC of the first mode is consistent with the increase in the damage severity. Due to the nodes of higher-order modes and the effect of noise, second-order and third-order modes cannot be used for damage identification;
2. After identifying the damaged edge, the specific damage location of the structural sealant can be further identified through the difference in BMC. Based on the assumption that the differences in the BMC caused by noise follow a normal distribution, the  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Specimen**} & \multirow{2}{*}{**Edge**} & \multicolumn{5}{c}{**Case**} \\ \cline{3-6}  & & **5** & **6** & **7** & **8** & **9** \\ \hline A & E\({}_{\text{b}}\) & 3 & 3 & 3 & 3 \\ \hline B & E\({}_{\text{b}}\) & 4 & 4 & 4 & 4 & 4 \\ \hline \hline \end{tabular}
\end{table}
Table 7: Identified damaged location of specimen-A and B.  
Figure 17: The difference in the BMC (**a**) Edge b (specimen-A), (**b**) Edge b (specimen-B).  
midpoint of the damage location can be identified. As the number of measurement points increases, the identified location would be more accurate, but the required labor in actual engineering increases. Usually, the number of measurement points on single-edge must reach more than 5;
3. The method can be affected by the damage severity and noise in actual use. When the damage severity is small or the noise is high, the accuracy of this method decreases. When the damage severity exceeds 4%, the two-stage damage localization method can effectively identify the midpoint of the actual damage range.  
However, in this study, only the damage identification of the frame-supported panel unit was carried out. In the future, further research is needed to identify the damage of other forms of glass curtain walls. Because the damage location is random, the number of measurement points also needs to be further discussed.  
Conceptualization, D.P.; Methodology, X.Z., K.J. and D.P.; Formal analysis, K.J.; Investigation, K.J.; Resources, X.F. and N.H.; Writing--original draft, K.J.; Writing--review & editing, D.P. All authors have read and agreed to the published version of the manuscript.  
This study was supported by the Opening Funds of the State Key Laboratory of Building Safety and Built Environment and National Engineering Research Center of Building Technology (No. BSBE2022-06). The support is gratefully acknowledged.  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors on request.  
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.