**4. Conclusions and Further Work**

This paper presents the results of experiments and numerical simulations of a case study involving a flat and cylindrically curved IGU subjected to characteristic climatic actions given in the standards.

It was found that the curvature of the component panes significantly influences the internal pressure, deformation pattern, and stress in the glass of the IGU subjected to climatic loads. The flat IGU uniformly bulges (the pillowing effect), while the curved IGU tends to 'flatten' with lifting short edges. This phenomenon is also reflected in the stress distribution. Its maximum value changes location from the centre of the pane (flat IGU) to the centre of the long edge in the curved IGU. The value of principal tensile stress increases significantly by more than 500% in the curved IGU. This finding is critical for the structural design of the panes and the secondary sealant and therefore justifies undertaking the research topic.

It should be emphasised that the above conclusions are valid only for the assumptions used in the case study. The influence of the curvature of the component panes of an IGU on the resulting internal pressure is highly complex and requires further research. It includes investigations of the impact of spacer stiffness and the interface between the glass panes and the spacer.

**Author Contributions:** Conceptualisation, M.K. and K.Z.; methodology, M.K. and K.Z.; software, M.K. and K.Z.; validation, M.K. and K.Z.; formal analysis, M.K. and K.Z.; investigation, M.K. and K.Z.; resources, M.K. and K.Z.; data curation, M.K. and K.Z.; writing—original draft preparation, M.K.; writing—review and editing, M.K. and K.Z.; visualisation, M.K. and K.Z.; supervision, M.K.; project administration, M.K.; funding acquisition, M.K. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the research project "Analysis of internal pressure in 3D bent insulated glass units" (grant number 2021/05/X/ST8/00168) financed by The National Science Centre (NCN) within the MINIATURA 5 programme.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Data will be provided upon request.

**Acknowledgments:** The authors thank their colleagues and students from the Faculty of Civil Engineering at the Silesian University of Technology, Gliwice, Poland, for their support during the experiments. Moreover, the insight and expertise provided by Zbigniew Respondek, PhD from the Faculty of Civil Engineering at the Czestochowa University of Technology, Cz ˛estochowa, Poland, is acknowledged. The publication cost of this paper was covered with funds from the Polish National Agency for Academic Exchange (NAWA): "MATBUD'2023—Developing international scientific cooperation in the field of building materials engineering" BPI/WTP/2021/1/00002, MATBUD'2023.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


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