## 3 Finite Element Method (FEM): Seismic Performance of Curtain Wall
### Dynamic Seismic Analysis of Curtain Wall by AAMA 501.6 Standard  
Based on the previous single-frame curtain wall static analysis, the results of the numerical analysis on the \(X\)-axis ensure the validity of the numerical analysis on the remaining axes. Therefore, the dynamic seismic performance assessment in this study was conducted mainly on numerical analysis in the \(X\)-axis direction. Structural performance was predicted and evaluated when dynamic displacement simulating the AAMA 501.6 seismic waveform was applied to the lateral axis (\(X\)-axis). The authors intended to verify whether the vulnerabilities that occur in the non-seismic curtain wall system when dynamic drift occurs can be compensated by using mobile fasteners and inter-story separated modules by comparatively analyzing the seismic performance according to the structural analysis results. In addition, to minimize the length of the linear guide, numerical models were additionally created in which the length of the linear guide was reduced to 100 and 50 mm based on the 150 mm, which is the basic shape of the curtain wall module introduced in the previous section. Then, according to the AAMA 501.6 standard, the behavior and seismic performance of the curtain wall according to the decrease in the linear guide length under dynamic drift were compared. Figures 29-34 show the results of finite element analysis, and compare the Von Mises stress distribution and the degree of deformation of the exterior material according to the linear guide length when AAMA 501.6 dynamic drift was applied. Figure 28: Comparison of appearance changes under applied \(Z\)-axis inter-story drift: (**a**) non-seismic curtain wall module; (**b**) seismic curtain wall module. Figure 31: Seismic curtain wall deformation: linear guide length 100 mm. Figure 30: Stress distribution applied to each member: linear guide length 150 mm. Figure 29: Seismic curtain wall deformation: linear guide length 150 mm. Figure 34: Stress distribution applied to each member: linear guide length 50 mm. Figure 33: Seismic curtain wall deformation: linear guide length 50 mm. Figure 32: Stress distribution applied to each member: linear guide length 100 mm. Table 10 shows the maximum stress generated in each member. According to the FE analysis results, it was found that the stress distribution in each member was greatest in the mullion when the dynamic drift was applied. When dynamic drift was applied, the displacement could be controlled because the moving clip of the linear guide moves along the rail in the axial direction in which the drift is applied. Based on this principle, the stress applied to the exterior material is absorbed and dissipated. The results according to the change in the length of the linear guide show there were no partial dropouts and breakages of each member as a whole. As the displacement absorption section decreased to 100 and 50 mm based on 150 mm, the stress applied to the curtain wall gradually increased. It was found that the stress increased linearly with the decrease in the length of the displacement absorption section, which is shown in Figure 35. When the length of the linear guide was reduced to 50 mm, there was no damage to the glass facade, as shown in Figure 36, but as the displacement increased, the upper fastener was deformed, and a slight gap was found in the member junction between aluminum and PVC. However, compared with the deformation of the non-seismic curtain wall shown in Figure 37, it was judged that even if the length of the linear guide is reduced to 50 mm, it has sufficient seismic performance in response to dynamic seismic waves. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Linear Guide Length (mm)**} & \multicolumn{5}{c}{**Peak Stress (MPa)**} \\ \cline{2-6}  & **Aluminum** & **PVC** & **Fastener** & **Linear Guide** & **Glass** \\ \hline
50 & 409.9 & 10 & 116.1 & 53.4 & 4 \\
100 & 192.3 & 3.8 & 61.2 & 18.7 & 1.4 \\
150 & 12.8 & 0.35 & 14.4 & 7.29 & 0.45 \\ \hline \hline \end{tabular}
\end{table}