Simulation models from various disciplines have been taking on more and more tasks in planning and development processes for decades. At EDAG, we use these methods and tools on a daily basis in industrial and vehicle development projects to create new products according to the latest standards. To define the use of the right material, in the right place, in the right quantity, we rely on a wide range of CAE simulation software - for the highest quality, also in acoustic terms.
Acoustic tests with virtual simulation
In contrast to the other senses, the sense of hearing is permanently "online" 24/7 and therefore does not experience any breaks. The sense of hearing, which perceives the acoustics in our environment, serves us for orientation, communication, danger prevention and emotional connection. It is therefore a tool that enables us to live safely connected in groups.
In the context of acoustic simulations, the range of questions, dimensions and applications is very diverse. The applications range from questions such as why does a dolphin hear some sounds better, to the interior acoustics of vehicles, to squeaking and rattling noises, to drive noises and noise emissions from wind turbines in wind farms. From the small to the large, corresponding predictions can be made using virtual observation.
Acoustics is generally concerned with the propagation of sound caused by oscillations and vibrations. The two core areas of structure-borne sound and airborne sound are the focus of the development of high-quality products.
Structure-borne sound of a dolphin ear
Using the example of the dolphin ear, EDAG was able to demonstrate that these marine mammals have a particularly good hearing range within the hearing range of 20 Hz to 150 kHz. This range is noticeable in that the dolphin perceives certain frequencies in the 60 kHz to 100 kHz range particularly well.
Figure 1: Functional principle of the middle ear of dolphins and FE model of the ossicular chain
Using FEM techniques, we developed a structure-borne sound model of the ossicular chain, which showed that hearing can be reproduced qualitatively well. For this purpose, an inverse method was used, taking into account the transmission power to be invested, and compared with values noted in the experiment.
Figure 2: Transmission power-related transfer function curve
This investigation demonstrates the efficiency of acoustic simulations using FEM techniques, showing that very good results can be achieved within small structures and a large frequency bandwidth. Although this investigated mechanical system cannot be improved, it provides insights into the behavioral patterns of these animals and allows us to understand why certain behaviors occur in this case.
Why good room acoustics are important
Another topic in the field of airborne noise that we at EDAG deal with and support projects with is room acoustics, which will be explained in more detail below.
Room acoustics play an important role in our daily lives. We spend a large part of our everyday lives in closed rooms. The increase in illnesses that manifest themselves in the human psyche can be attributed to the stress that affects people. Such stress is also caused by increased sound and noise levels, among other things.
Concentrated work in an open-plan office is only possible if the ambient noise at the workplace is not perceived as disturbing by the employees. Good room acoustics planning can positively influence these noises through targeted design and the right choice of materials for people.
The advantage results not only in compliance with regulations and recommendations, but also in employee satisfaction. Satisfied employees complete tasks with more pleasure and in less time, as stress-induced break times are reduced. The aspects of concentrated working are not only limited to office spaces, but are also crucial in the manufacturing sector of industry. The methods of room acoustics can also be applied in production halls.
The transformation of the industrial society into a service society is in full swing. As a result, an increasing demand for office space, whether as new buildings or conversions, can be predicted. In order to support this demand for "quiet" office and work spaces to be planned with room acoustic simulation, we apply the necessary standards before the first brick is erected or dismantled.
Figure 3: Sound level (A) before and (B) after
In public areas, swimming pools, sports halls and concert halls should be mentioned, which require consideration of the room acoustic design. All of these places can emphasize their added value in terms of quality through good room acoustics, especially if they are used for longer periods of time.
A non-everyday area within our room acoustics simulation is the assessment of shooting ranges in the form of indoors shooting ranges. Corresponding workplace regulations also apply here as to how such small rooms should be designed. The dwell time of the respective stand supervisor and the trainer within the indoor shooting range can be assessed by means of room acoustics simulations before the first shot, using the expected exposure values.
Figure 4: Sound propagation of a shot in 2-D and 3-D
Within the room acoustic simulations, the common evaluation parameters such as reverberation time, speech transmission index, decay rates, etc. are considered and classified according to the current standards and regulations. The classification of room use can also be assessed a priori, thus guiding planning towards the intended goal.
Choice of acoustic measures
In order to carry out the aforementioned optimization of position, material and quantity of acoustic measures, materials from common manufacturers or potential suppliers can be considered. Alternatively, we put together combinations of acoustically effective materials as a combination and use the resulting properties for room acoustic optimization.
In this way, the available wall and ceiling surfaces can be matched to the technically required frequency ranges. All this is also done on the basis of virtual simulations. For acoustic issues, we use common numerical methods such as FEM, BEM, SEA and ray-tracing methods to achieve the best possible virtual representation.
This has already enabled us to evaluate and implement various projects. The investment in the right acoustic measures for an optimized design led to an advantage in planning, not only functionally but also financially, thanks to the simulative support.
An initial acoustic inventory or a final validation of the measures developed can be checked by EDAG's own measurement team.
Conclusion
The implementation of technical simulations is a great advantage of the present day and state of the art in developments from a technical point of view. In particular, the simulation of room acoustics presented here offers added value in the equipping of workplaces and public spaces in general. The benefit pays off on the one hand in the form of optimized investments in the design of workplaces and on the other in the form of satisfied employees and users. Compliance with acoustic workplace guidelines is therefore also considered to be fulfilled.
If you would like to find out more about the use of acoustic simulations to optimize room and product acoustics - from virtual modelling to the implementation of individual measures - Andreas Pfeiffer, Project Leader NVH, will be happy to provide you with a personal consultation. Or download our white paper "Smart Acoustic Design: Better room acoustics for more productive working environments" here, which takes a closer look at how simulation-based planning, targeted material selection, and standard-compliant measures lead to noticeably better work quality and productivity in modern offices.
