Razvoj lesnih kompozitov z višjo zaščito pred udarnim hrupom za izboljšanje kvalitete bivanja / Engineered wood composites with enhanced impact sound insulation performance to improved human well being

Gre za skupen slovensko – avstrijski
projekt.

ANG

The most promising way to limit the negative impacts of the building industry is to force the use of wood, which is not only a renewable resource, but is also capable to sequester carbon dioxide from the atmosphere. The proper approach to promote the use of wood in buildings is to identify and challenge the drawbacks that come with it. The most commonly exposed prejudice is that wooden buildings are suffering on low sound insulation. More specifically, it is challenging to achieve high impact noise insulation due to the lightweight nature of the structural elements, which are more sensitive to excitation and typically lack sufficient damping that would restrain the propagation of vibrations. The proposed project aims at improving the impact noise insulation in wooden buildings by engineering a sustainable resilient layer. This done a fundamental assessment of the annoyance of impact noise in the built environment that surmounts standardized insulation ratings. Floating floors are the most effective and most common constructions used for impact sound insulation in buildings. The accessible and very effective solutions nowadays are cement based screeds that on top of negative environmental influence have also other drawbacks, such as high mass and extended drying time. In contrast, dry floor solutions are compact and can come with a high degree of prefabrication. Prefabrication and short building time are huge favorites among modern building systems. With this project we raise an engineering challenge ‐ to investigate the potential of creating a wood‐based resilient layer for use in the floating floor system. A hybrid‐type wood composite will be used for the resilient layer as it can fulfill two fundamental requirements: sustain high point loads and achieve low dynamic stiffness. At the same time the mass of such floating system can be reduced without compromising its impact insulation rating. Nevertheless, the mass reduction might produce discomfort for users which will be investigated throughout the project. The development of the resilient layer will follow numerical modeling predictions and experimental testing of samples will be performed to optimize the design. The main evaluation of the engineered resilient layer will however take place in relevant conditions ‐ in a representative set of  built environments in which the sound field and vibrations produced by impact noise sources will be recorded using a higher order Ambisonics system and a set of accelerometers. These environments will be later re‐created in laboratory conditions and perceptually evaluated by test subjects. Their preferences will be collected together with several physiological responses, including various cardiovascular indicators acquired through EKG (heart rate, heart rate variability), skin conductance/galvanic skin response and skin temperature. On this basis the annoyance of impact noise sources will be evaluated in different built environments and with different resilient layers installed. An important novelty of the proposed project is to evaluate noise annoyance by jointly investigating the response to vibrations and sound stimuli which are known to be correlated. Moreover, the perceptual evaluation will be conducted in laboratory conditions, which limits several methodological uncertainties. This approach has not been previously used in case if impact nose. With a positive outcome of the project, deeper understanding of the annoyance caused by impact noise is expected. This will improve the acoustic comfort in wooden buildings, which is currently questioned, and promote the use of wood in the built environment. The project includes four project partners that extend the main expertise of InnoRenew CoE in the field of wood composites. Numerical modeling will be conducted by University of Ljubljana (FMF) and TU Vienna, the building acoustics perspective will be led by IBO and the perceptual evaluation will be led by University of Primorska (FAMNIT).