Beta 1

Author Chen, Xinyi
Supervisor Jacobsen, Finn (Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Ohlrich, Mogens (Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Larsen, Martin (OTICON)
Halkjær, Søren (OTICON)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2008
Abstract Rubbers are very important material with versatile engineering applications. One of the main purpose of the applications is to isolating vibration that might cause damage to the mechanical system. When a rubber material is used for this purpose, the elastic modulus and the damping property of the rubber is the main concern. The elastic modulus determines how much vibration is transmitted through the rubber and the damping property determines how much is absorbed and dissipated. A rubber suspension in the hearing aid apparat is such a product. It serves as a receiver holder as well as avoiding the transmission of the vibration from the receiver to the shell of the hearing aid. Since a hearing aid is used as a sound transmitting media. The interesting frequency range is broad (up to kilohertz range). The modulus and the damping properties of this range is called the dynamic property, i.e. dynamic modulus or damping, which is a dierent concept to the static modulus or damping. However, in hearing aid industry, the rubber material for the suspension is chosen more empirically. Neither the static modulus or damping nor the dynamic modulus or damping of the material is clear. It is therefore an interesting topic for the industry to investigate the rubber material more theoretically. This motivates the investigation of this report. The rubber suspension is investigated both from a material point of view and a structural point of view. The dynamic elastic modulus (Young's modulus here) and the damping are derived for the rubber suspension by dierent methods. The results deviate with each other because of the inherent feature of the method itself as well as the uncertainty caused by the experiments. However, a common conclusion is that both the Young's modulus and the damping of the rubber suspension are frequency dependent in the frequency range of concerned.
Pages 111
Original PDF Xinyi_Chen.pdf (3.60 MB)
Admin Creation date: 2009-03-26    Update date: 2009-08-07    Source: dtu    ID: 240727    Original MXD