Figure - available from: Applied Sciences
This content is subject to copyright.
Source publication
![Deformations UZ [m] of the model in the case of injection of 100 mL of...](publication/367266435/figure/fig5/AS:11431281357671784@1744025617511/Deformations-UZ-m-of-the-model-in-the-case-of-injection-of-100-mL-of-air-test-series_Q320.jpg)
Insulating glass units (IGUs) are building components that show a particular structural behavior. Although such structures have many advantages from the point of view of thermal protection of buildings, they show particular structural behavior under climatic loads. The inability to equalize the pressure with the surrounding atmospheric air causes o...
Citations
... Nevertheless, the ature describes such studies, most of which have been conducted recently. Tests o deflection of IGU components in operational conditions are described in [19] and in ulated pressure or temperature changes in [10,20,21]. In [22], Galuppi et al. experimen verified the BAM model [14] for double-glazed IGUs, in the range of line-distributed concentrated loads and also at high temperature. ...
... Nevertheless, the literature describes such studies, most of which have been conducted recently. Tests of the deflection of IGU components in operational conditions are described in [19] and in simulated pressure or temperature changes in [10,20,21]. In [22], Galuppi et al. experimentally verified the BAM model [14] for double-glazed IGUs, in the range of line-distributed and concentrated loads and also at high temperature. ...
... The tests indicated that the deflection of the component slab has intermediate values between those estimated for a simply supported and restrained pane. Similar tests (an IGU was placed in a structure simulating a window frame) described in [21] showed that the measured deflection and stress in the center of the panes differed from the theoretical values for simple support, which may suggest elastic support. Regarding the theoretical analysis of the problem, recently, Galuppi and Zacchei [35] published a theoretical and numerical analysis on the transfer of external load between the panes of double-glazed IGUs, assuming their support with elastic beams, depending on the coefficients describing the bending and torsional stiffness of the support beams. ...
Insulating glass units (IGUs) are the most common filling for external building envelopes. These elements have many advantages related to the thermal protection of buildings. However, some climatic loads are generated or modified due to the sealed gas cavity between the glass panes. The gas enclosed in the cavities changes its parameters under external load, which affects the operational deflection and stress in an IGU. In most computational models describing this phenomenon, the component panes are assumed to be simply supported on the edge spacer, which is considered a sufficient approximation. This article, which continues previous work, assumes that the component glass panes can be supported elastically at the edges. The parameter describing this connection is rotational stiffness. Based on the theory of linear–elastic plates, coefficients were determined to calculate the change in cavity volume, deflection, and stress in glass panes. Then, the results of calculations of the influence of rotational stiffness and static values in exemplary IGUs of various structures, loaded with changes in atmospheric pressure and wind, are presented. It was found that a feedback loop occurs here. The deflection and stress in elastically supported single panes are lower than in the case of those simply supported. However, the lower susceptibility to deflection of the component panes weakens the gas interaction in the cavity, and the resultant load on these panes increases. The influence of rotational stiffness on the resulting static values may therefore vary. In the analyzed examples, this influence was primarily negative for symmetrical loads and clearly positive for wind loads.
... However, the present study does not consider these aspects. 2. The effect of the ambient pressure and temperature changes on the cavity pressure of the IGU, i.e. climate loads (Buddenberg et al. 2016;Kozłowski et al. 2023), are neglected in this study. 3. Note that the used PSO algorithm is the same as in the Authors' earlier studies (Heiskari et al. 2022b(Heiskari et al. , 2023, but it is presented here again for clarification purposes. ...
... McMahon [16] simulated the loading by inducing a pressure difference on both sides of the IGUs. Stratiy [4] and Kozłowski et al. [17] simulated climatic loads by injecting/extracting gas into/out of the cavity. ...
Insulating glass units (IGUs) have tight cavities filled with gas in their structure, which results in a specific manner of transferring climatic loads. Under the influence of these loads, the gas in the cavities changes its parameters, which affects the resultant load on each of the glass panes in the unit. In the computational models described in the literature concerning this phenomenon, vertical location of IGUs is usually assumed. However, nowadays glass roof-ceilings and rooflights with triple-glazed IGUs located diagonally or horizontally are more and more often implemented. In this case, an additional factor influencing the static quantities in IGUs is the own weight of glass. The aim of the article is to analyze the influence of the horizontal location of triple-glazed IGUs on their deflection and stress under climatic load. The analysis was carried out using own analytical model. Based on the presented examples, conclusions were drawn about the resultant loading, deflection and stress in IGUs of various structure and dimensions with climatic factors. It was shown that extreme annual temperature changes and a large increase in atmospheric pressure are the most dangerous in the context of the possibility of excessive deflections. The horizontal location, on the other hand, mitigates the effects of atmospheric pressure drop and wind suction.
... They also discussed double and triple glass units, as well as the sun blinds, and color affecting the heat transmittance [11]. Respondek et al. [12] and Rashid et al. [13][14][15] made reviews and research on heat transmission regarding Reynolds , Nusselt s, and Prandtl s numbers in nano-and phase-change materials. P. Gallo and R. Romano investigated in 2017 the SELFIE system , developing a multifunctional, adaptive, and dynamic façade aimed at enhancing the energy performance of buildings in the Mediterranean region. ...
... They also discussed double and triple glass units, as well as the sun blinds, and color affecting the heat transmittance [11]. Respondek et al. [12] and Rashid et al. [13][14][15] made reviews and research on heat transmission regarding Reynolds', Nusselt's, and Prandtl's numbers in nano-and phase-change materials. P. Gallo and R. Romano investigated in 2017 the 'SELFIE system', developing a multifunctional, adaptive, and dynamic façade aimed at enhancing the energy performance of buildings in the Mediterranean region. ...
... For forced convection, the Reynolds number (Re) is included, and the air film temperature is given as the average temperature between the surface and air (T 1 + T 2 )/2, where v is wind or airspeed like shown in Formula (12). ...
Although glass façades have been on the market for over a century, new improvements, following sustainable standards, are still being invented. An improvement of the actively maintained CCF has occurred in passive maintenance with natural ventilation of the cavity and insulation glass unit placed on the external side, which has served as a true motivation for further research. To develop the idea, a new type of CCF was invented, followed by the creation of the software, whose purpose is to determine optimal CCF façade components. During this research, an experimental and mathematical model was made regarding the thermal behavior, later validated by the measurements on-site in Rugvica, Croatia. Using simplified but unconventional methods, numerous formulae and variables, a simulation of climatic loads onto the CCF was conducted. Validations of the thermal model were made during winter and summer periods for southern and western façade orientation, explaining how heat transfers from the environment to close cavity façade elements. It was found from the analysis that air temperatures of the façade elements follow the outer air temperature, by constant air exchange with the outer space. The results showed great potential with up to 3 °C (5–10%) of difference in experimental and calculated results, thus creating a basis for further improvement of the software with the addition of structural and hygric behavior of the façade element, regarding climate conditions.
... That is, laminated glasses 1 and dynamic loading are studied in the future, as both are highly present in ships. Further, the effect of variation in ambient temperature and pressure, i.e., the climate loads [14][15][16], and their combined effect with an external load on the response was studied in [17]. There, the maximum stress increased approximately by 12% due to the climate loads as per DIN 18008-1 [18] (omitting altitude change component), which should be considered when analyzing real IGUs. ...
The increasing complexity and size in cruise ships demands for lightweight structures and practical but accurate design methods. Conventionally, the focus has been on the steel parts of the ship, as they make most of its weight. However, the proportions of other materials are increasing. Therefore, this study attempts to provide better understanding how one could reach the lightweight designs of insulating glass units (IGUs) in ships. These are windows where at least two glass panes are separated by a hermetically sealed cavity. They are thin-walled structures that benefit not only from the geometrically nonlinear behavior, but also from the load sharing. Considering these effects, their behavior is studied using the nonlinear Finite Element Method and Particle Swarm Optimization. Different design criteria are imposed on the thickness determination of the glass panes with different shapes. Rectangular, triangular, and circular shapes are considered. The results show that the triangular shapes have the least weight for a given area when the deflection criterion is the dominating one. When maximum principal stress is the thickness defining criterion, the shapes perform almost equally well. The
ratio between the pane thicknesses had the most influence on the behavior of the IGU. As it increases, i.e., one pane is significantly thicker than the other, the load sharing percentage drops, but it provides the most lightweight solution. Closer it is to 1, more equally the structural stresses are divided between the panes, i.e., redundancy is achieved. Finally, it is possible to establish a simple but effective method for the thickness determination of these IGUs using the results of this study. However, more work is required, including numerical analysis and experimental testing.
... This set-up was chosen to detect any deformation of the IGU specimen under loading. A single series of tests involved injecting or withdrawing a defined air volume into/from the IGU cavity [7]. After the procedure, pressure measurements were performed for 5 min, until the stabilisation of the pressure. ...
... The numerical models differ only by the volume of injected/withdrawn gas, whereas other parameters, such as the geometry of the sample, material properties, and boundary conditions, remain the same. Since creating eight numerical models in the ABAQUS GUI (Graphical User Interface) would consume significant time, a Python script A single series of tests involved injecting or withdrawing a defined air volume into/from the IGU cavity [7]. After the procedure, pressure measurements were performed for 5 min, until the stabilisation of the pressure. ...
Curved glass enables designers to achieve unparalleled innovation in creating modern and undulating shapes for building enclosures. However, the curvature of panes changes the static and especially the dynamic behavior of the panes under loading. Studies on low-velocity impacts on curved glass have been limited and have primarily involved numerical studies. This paper experimentally investigates the dynamic response of cylindrically curved glass panes under a low-velocity impact. A flat, 5 mm thick, single-pane geometry with three curvature radii and the lack or presence of movement restraint is considered. Special attention is also paid to the variations caused by impacting bodies involving different stiffness, mass, and geometry parameters. It was found that flat plates have a lower capacity to dampen oscillations, resulting in longer decay times compared to curved panes. For impactors with a lower stiffness, the glass panes experience uneven oscillations at the moment of impact, followed by a chaotic period of transient vibrations before reaching a stationary state. This contrasts bodies with greater deformability in which the main dynamic behavior follows a more predictable pattern.
