Sound absorption coefficient correlation between experimental studies and numerical analyzes

Along with the adaptation of the automotive industry to evolving technologies, the best way to meet customer expectations has been the main goal of the industry. Since customer expectations are directly related to the quality perception, it is expected that vehicles marketed to the market will have quality in many terms. It is possible to extend the quality expected subjects to vehicle characteristics. These are the main topics such as vehicle performance, fuel consumption, durability, ergonomics, geometric design elements, vehicle dynamics, multimedia systems, interior and exterior quietness. Interior noise level is a quality parameter that can be easily affected directly by the people in the vehicle during the drive. The wind noise, the road noise, the noises of the engine entering the vehicle, the sounds coming from the power train have an important effect on the customer. These are the main criterias of choosing which vehicle to buy by a customer. It is possible to work on the sound source to solve the noise problem. It is one of the search for solutions to decrease to the minimum sound levels by keeping up with the technological advances that develop on each piece. The other one is based on the absorption of the sound while transferring it. Utilizing the properties of the acoustic materials, it is obtained to decrease the level of the noise from the source to the interior of the vehicle. Although quality is among the main objectives, the costs are also at the top of the critical issues for the automotive sector. The challenge of finding the optimum that lies at the base of engineering is also a challenge in this respect. Efforts are being made on what can be done without compromising the interior quietness, at minimum cost, without affecting vehicle dynamics and without increasing fuel consumption. Various test equipments are used to know the characteristics of the acoustic materials and to observe its performance. As a result of these equipments, design inputs are formed. Achievement of each of these test results is not easy to achieve when acoustic improvement is targeted. First of all, equipments at very high cost are required. There is a need for labor to operate these equipments. In order for the tests to be carried out, the delivery of the acoustic materials must be expected. After long time tests are carried out and the materials planned to be applied on the vehicle are shaped according to the results. In this thesis, basic sound information will be examined primarily for the theoretical infrastructure. Subsequently, numerical analysis methods will be discussed. Examination of the sound absorption characteristics of acoustic materials means that the expected quality is achieved by minimizing the costs in the direction of the thesis. It will be examined how close it is to test results using vibroacoustic simulation software to protect against test costs and time loss. In this scope, alpha cabinet test results and impedance tube test results will be collected. In the VA One (Vibro acoustic simulation software), the analysis will be done in the alpha cabinet to be modeled and the models will be operated. When the results obtained are compared, it will be observed what the acoustic consequences of taking the design inputs from the VA One will be observed while the vehicle is being designed and the parts are not yet present.