- Predicting the sound absorption coefficient and the transmission loss with high accuracy
- Modeling of poro-elastic materials using the Biot's theory
- Impervious materials such as plates or membranes can be included in a layer
- Acoustical performance prediction of various multi-layered and complicated structures
- Various incident conditions like oblique incidence or random incidence (statistical incidence).
- Short-time prediction by using the numerical calculation with the transfer matrix method
When one thinks of absorbing material, many people imagine a porous material like glass wool. This material has a good efficiency for heat insulation and has been used frequently.
Also, since the heavier materials have better sound insulation performance, a steel plate or concrete is considered as sound insulation material. These materials have been used because of convenience and reasonable cost, and it seems that another materials cannot be used instead of that.
Recently, the materials are requested, which are thinner and lighter and more efficient for both sound absorption and insulation. Taking for an example of automobile; sound insulation performance is required for shutting out the road noise or engine noise into the cabin, and sound absorption performance is required for designing or obtaining the comfort in a cabin. Moreover, the material should satisfy both the sound insulation and absorption efficiencies. Accomplishing the development, the material is not a single layer structure but a multi-layered structure which combines different materials in many cases.
Generally speaking, the development of the material is subsequent procedure. First, new material is manufactured by way of trial, and then the acoustical properties of that are measured. However, this way is inefficient, takes too much time, increases the cost, therefore, CapMLS can solve this problem.
CapMLS can build multi-layered structures which are combined with poro-elastic materials modeled by Biot theory, impervious elastic materials like a steel plate or a membrane and air layers. The absorption and insulation efficiencies of the material for various sound incidences are predicted at the same time, and the desired data are collected timely.
Since the CapMLS is capable of predicting precisely the acoustic characteristic of the material, it can be released from the trial manufacturing during the development process.
The following two figures describe the calculated results by CapMLS, these are compared with the measured results.
The left figure shows the normal absorption coefficient of the multi-layered structure made from a glass wool (density: 96 kg/m3) with thickness of 25 mm and a film with thickness of 0.05 mm. The measurement equipment is our product, the normal incident absorption coefficient measurement system Winzac.
The right figure shows the transmission loss of the multi-layered structure made from a steel plate with thickness of 0.8 mm, a felt with thickness of 20 mm and a film thickness of 0.05 mm. The measurement system is our product, the transmission loss measurement system in our acoustic laboratory.
Both calculation examples are close to each measured result, these are examples of excellent precision by CapMLS.
Normal absorption coefficient of glass wool
(density: 96 kg/m3, thickness: 25mm) +
film (thickness: 0.05mm)
Transmission loss of a steel plate
(thickness: 0.8mm) +
felt (thickness: 20mm) +
film (thickness: 0.05mm)