## 6 Numerical Results
### Performance of Full-Size Sandwich Element with Openings  
The concept described for the full-size element, as per Figure 1, was applied in this analysis. More specifically, the FE-model presented in Section 6.2 was modified to contain window and door openings. To analyze the appropriate placement of the connectors in this given element configuration, three cases were considered, namely Case I-III. The first case (Case I), i.e., reference case, consists of the connectors being placed at the outer vertical edges and at the positions of the anchors as was the case in full-sandwich element with a 2.0 m connector spacing. Furthermore, the analysis consisted of solely applying _LC2_, defined in Table 3, as this was found to be the most critical load case at both the SLS and the ULS. In _LC2_, the external facing of the sandwich element is under suction and the internal facing is under pressure.  
The deformed shape together with the out of plane displacement and cracks, represented as maximum principle plastic strain, are shown for the SLS in Figure 17. As can be seen, the displacements of the element are rather small, with a maximum value of approximately 3 mm. However, the displacements due to local bending are rather pronounced at the openings, especially above and below the door opening. This also leads to severe cracking of the facing in these regions. Cracks were also observed around the connector attachments at the location of the upper and lower anchors and smaller cracks at the corners of the openings.  
Figure 16: Out-of-plane deformation plots for _LC2_ at SLS for outer facing (**a**) and inner facing (**b**) for element with 0.5 m connector spacing, and outer facing (**c**) and inner facing (**d**) for element with 2.0 m connector spacing. Only half of the element is shown due to symmetry.  
In the second case (Case II), additional connectors were placed between the outer and inner facings, horizontally along the upper and lower edges of the element. This stiffens the entire element and consequently reduces the displacements of the element, especially at the door opening; see Figure 18a. Furthermore, the amount of cracking was also drastically reduced, as depicted in Figure 18b. Nevertheless, the local bending of the outer facing was quite noticeable around the openings. To overcome this phenomenon, additional vertical connectors were placed on each side of the openings, together with one additional short connector below each window opening in the third case (Case III). These extra connectors reduced both the element's global bending about the x-axis, as per Figure 10, and the local affects around the openings, such that there were reduced displacements and cracking; see Figure 18c. The maximum displacement at the SLS was reduced to slightly above 1 mm and first cracking in the outer facing took place at load levels above the SLS. Accordingly, the cracking at the ULS is shown for Case III in Figure 18d.  
Figure 17: Case I: Contour plots of out-of-plane displacement (connectors in red) (a) and cracked regions at the SLS (b).  
Figure 18: Case II: contour plots of out-of-plane displacement (**a**) and cracked regions at the SLS (**b**); and Case III: contour plots of out-of-plane displacement at the SLS (**c**) and cracked regions at the ULS (**d**).  
A summary of the FEA results pertaining to the sandwich element with openings with different connector placement cases (Cases I-II) is provided in Table 6. For Cases I and II, the pull-out capacity of the connectors resulted in the limiting factor for the maximum wind load resistance, while the capacity of the anchors was governing for Case III.