The current design of workspaces for companies is focused on minimalistic and modern styles prioritizing the aesthetic appearance with illuminated open spaces and the use of glass walls. If the acoustic performance is not considered, inappropriate Reverberation Times (RT) might lead to difficulties for hearing a speaker or teacher during courses and conferences, causing problems in the learning process. Additionally, there might be high sound transmission between adjacent work rooms. This paper presents the development and experimental validation of numerical models using Statistical Energy Analysis (SEA) to calculate the sound reduction index through a glass wall that separates two adjacent work rooms. These structures are dedicated to conferences and educational uses but cannot be properly used due to their high sound transmission and inappropriate reverberant time. The sound insulation prediction results are validated with experimental measurements carried out in the adjacent rooms under the standard ISO-140. Afterwards, a SEA model is used to provide some acoustic correction design guidelines for these types of constructions. To improve the acoustical performance in the rooms, the acoustic effects of different absorbent panels placed on the walls and ceiling were investigated, choosing a suitable material that complies with the recommended ranges of RT and with less amount of absorption area. The SEA model is then used to understand the effects of openings size between the panels that make up the glass wall on the sound insulation capacity between rooms. Finally, a SEA model is reformulated to quantify the effect of the application of double walls for sound insulation between rooms, which implies the increase of weighted sound reduction index in 9 dB with respect to measured data.

Visual defects, in particular haze, in glass and façade technologies can significantly impact the aesthetic quality and human experience of daylight and views in buildings. The glass and façade industry increasingly requires methods that can objectively predict and measure the subjective user experience of haze. This is required to appropriately inform the manufacturing process, ensuring optimal functionality and performance, and avoiding material waste and economic losses due to the replacement of defective glazing. Existing methods for measuring haze are not appropriate for assessing large samples, either at manufacturing sites or in-situ. However, haze defects are often only exhibited and visible when glazing is produced in large samples or installed under real luminous conditions. This paper introduces a novel luminance-based method that measures haze by evaluating the halo around a light source that is observed through the glazing. This method is initially tested in a controlled laboratory setting on small glazing samples with varying level of haze. The halo serves as a proxy for haze severity and it is quantified by using luminance-based measurements. In this work, the newly-proposed method is verified by comparing the ranking in haze severity of different samples as performed by means of a standard haze meter and the newly proposed method. Additionally, the paper examines the dependence of this ranking on factors such as camera setup distance and light intensity. It was found that the proposed method was able to effectively ranks samples differing in haze intensity by more than 0.1 orders of magnitude. Positioning the camera closer to the glazing and using higher light intensity yielded more accurate results. However, for haze levels below 1% and differences smaller than 0.1 orders of magnitude, the accuracy is insufficient. To define the expected level of accuracy of methods for haze characterisation in-situ, the sensitivity of the human eye to haze under varying luminous environments and view content needs to be quantified.

Among a multitude of functions, the façade is responsible for providing sufficient thermal insulation and supplying the building interior with enough natural light. For the latter, transparent glazed areas are essential. However, compromises in terms of the glass-to-wall ratio are often necessary since large glazed areas lead to overheating in summer and heat loss in winter. A novel type of highly insulating translucent glass brick made from annealed glass and filled with aerogel granulate was developed recently as an alternative in this regard. The bricks are not supposed to replace the transparent glass areas, but to offer a translucent alternative for part of the otherwise opaque wall areas. This paper focuses on the structural behaviour of walls composed of such aerogel-filled glass bricks. The components of such a brick and their functions are described. Moreover, two prototype systems for supporting the bricks in translucent walls are introduced—one with interlocking connections and pre-stressed wires, the other with interlocking connections and edge clamping. Both systems are analysed in finite element simulations from a structural point of view under out-of-plane loading. The resulting global deformations as well as occurring stresses in different components are analysed. Based on the findings, advantages and limitations of the different systems are highlighted and suggestions for improved alternative systems for translucent walls with insulating aerogel-filled glass bricks are made.

Additive manufacturing of glass using laser powder bed fusion has been recently developed, demonstrating its potential to be applied in small scale applications such as flow reactors for the chemical engineering and pharmaceutical manufacturing industries. While previous research demonstrated that complex 3-dimensional shapes can be manufactured, built parts are often brittle, exhibit high porosity and lack transparency. This study employs a transient, heat transfer finite element analysis to shed light on the thermal response of laser—glass powder bed interaction and the impact of processing parameters. Through this understanding, the research seeks to identify practical strategies that can be employed to improve the quality and properties of the built parts. Bulk solid and powder soda lime silica glass properties are used as input in the model, while the laser heat flux and scan strategy, conversion of powder feedstock to bulk solid glass and heat losses from convection and radiation effects are introduced in the model through Fortran coding. The study showed that effective powder consolidation, resulting in well-defined geometrical features, is achieved for temperatures near the glass melting point. Additionally, uniform consolidation depths and widths can be achieved by increasing laser power, elevating substrate temperature and reducing scan speed within certain limits, whilst ensuring hatch spacing is below the corresponding single scan track width for unidirectional adjacent laser trajectories.

Soda-lime glass is a brittle and transparent material that is known for its rapid and sudden fracture behavior. Since the use of soda-lime glass in protective structures is increasing, a more comprehensive understanding of this challenging fracture behavior is needed. The aim of this work is to investigate how the load level affects the crack propagation and to generate an experimental database for L-shaped soda-lime glass specimens with curved crack paths. We designed a repeatable testing procedure which reveals the crack propagation behavior of the specimen and allows for extraction of valuable experimental data. A total of 20 experiments were conducted on L-shaped soda-lime glass specimens subjected to a controlled displacement. High-speed cameras were used to monitor the crack propagation and the high-speed footage was post-processed using an in-house procedure to extract the crack path and speed data. We found a positive correlation between the measured initial crack speed and the load level at fracture. The crack propagation path followed four distinct stages and was also affected by the load level at fracture. With this experimental database, we have provided important insight into how the load level affects the crack propagation in soda-lime glass.

Recently, the numerical simulation of the residual load-bearing capacity of laminated glass (LG) is an often discussed but not sufficiently solved problem in structural glass design yet. According to CEN/TS 19100:2021 (2021a), and CEN/TS 19100:2021 (2021b), the design in the Post Fracture Limit State (PFLS) is possible experimentally and numerically. Experimental verification requires large-scale component tests, which are often costly and time-consuming. The resource-saving numerical approach is to be preferred. However, at the moment, there is no sound numerical model capable of representing the complex load-bearing mechanisms of broken laminated glass (LG) in civil engineering practice. These mechanisms are the finite-strain response of the interlayer, the contact between glass fragments or shards themselves, and the bond between glass and interlayer. Delamination governs the latter one mainly. This work focuses on the experimental, mechanical, and numerical characterization of the finite-strain behavior of polymeric laminated glass interlayers at long load durations by the example of standard single-layer Polyvinylbutyral (PVB). Based on that, it introduces an approach enabling the simplified numerical simulation of LSG interlayers. The considerations rely on experiments and thermodynamic considerations.

This is the second of two papers concerning errors in the measurement of the thermal insulating properties of Vacuum Insulating Glass (VIG) due to non-uniformities in the heat flow due to the support pillars. Part 1 deals with the situation where the measurement area is in direct thermal contact with the glass sheets. This paper discusses how the non-uniformities and associated measurement errors can be reduced using thermally insulating buffer plates on each side of the specimen. A single parameter is developed that characterises the maximum error for measurement areas of all sizes. Values of this parameter are given for all practically relevant designs of the VIG and properties of the buffer plates. Methods are developed for selecting measurement conditions that lead to acceptable tradeoffs between reducing the errors associated with non-uniformities in the heat flow and errors due to heat flow through the edges of the specimen.

Non-uniformities in the heat flow through the support pillars in vacuum insulating glass (VIG) can lead to significant errors in the measurement of the thermal insulating properties of these devices. This paper discusses these errors in instruments for which the measurement area is in direct thermal contact with the glass sheets. The spatial non-uniformities of the heat flow in different VIG designs are modelled using the finite element method. For measuring areas with large dimension compared with the separation of the support pillars, the errors are unacceptably large for all practical designs of VIG when using guarded hot plate instruments. These errors are less for heat flow meter instruments due to the construction of the heat flux transducer.