Some people know more about their neighbors than they would like to. Whether the other tenants are just now listening to music, watching television, having visitors, vacuum cleaning or washing clothes - its not possible to not overhear these things, because sound finds its own way.
Only the best possible insulation of the walls helps here. Manufacturers of partition walls will possibly have to think further ahead in future than they have up to now: Christoph Kling shows in his dissertation at the Physikalisch-Technische Bundesanstalt (PTB) that the repercussion of sound from adjoining walls has previously been taken too little into account, even though it considerably affects the sound absorption capability of some walls.
In the frame of a doctoral thesis basic investigations into damping effects in the field of building acoustics have been carried out. Special interest is paid to the damping of a partition wall in a laboratory test facility. This damping directly affects sound insulation which is the most important quantity in building acoustics.
In accordance with the results of earlier examinations, investigations into damping effects in the field of building acoustics were applied to small downscaled models. These offer the advantage of the exact execution of construction and of freely selectable material properties and allow idealised constructions to be realised. Firstly, the necessary theoretical and experimental bases were provided for the design of the downscaled models.
Extensive investigations into material properties led to the parameters required for the experiments and simulations. Thereafter, the individual effects that lead to the damping of the partition wall were determined as loss factors by experiment. A simulation undertaken by means of statistical energy analysis (SEA) allowed detailed insight into the energies and power flows of the system in total to be gained. Both the experiment and the simulation showed in agreement that the power flowing from the facility into the partition cannot be neglected a priori as has been common up to now. Depending on the laboratory situation, effects which have been thought of as loss effects to date can be turned into gain effects for the partition.
Since the power flows are the basis for the treatment of loss factors which are the measurement quantities for the damping of a partition wall, the complexity of power flows requires a rethink. Previous conclusions and measurement procedures must be tested for validity. Particularly, the standard procedure for measuring the total loss factor, which is the main measurement quantity for damping in practise, was analysed by a transient SEA simulation. In agreement with model measurements, it could be shown that, due to the complex power flow in a wall test facility, the total loss factor is determined as much too low for typical standard situations.
The insights gained about the damping of a partition wall in a building acoustics test facility explain previous discrepancies but also raise some new questions of a basic nature. In future, more effort will be required in practise to determine the influence of damping. This thesis offers a starting point for that.
Imke Frischmuth | alfa
Modular storage tank for tight spaces
16.03.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
Smart homes will “LISTEN” to your voice
17.01.2017 | EML European Media Laboratory GmbH
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
24.05.2017 | Event News
24.05.2017 | Information Technology
24.05.2017 | Awards Funding