Principle of AlphaCell

By means of a simple “Drag&Drop” functionality, the single layers of the multi-layer system are assembled one by one. Subsequently, the excitation conditions in terms of airborne sound and structure-borne sound as well as the specific parametrized calculation models for the different materials can be chosen independently.

All material parameters required for calculating the vibro-acoustic properties can be assigned from a material database. By modifying the different geometrical and material-specific parameters, the vibro-acoustic behaviour of different multi-layer systems can be compared and optimized very efficiently and effectively.

Calculated indicators

Amongst others, the following indicators can be computed:

• sound absorption coefficient, sound reflection coefficient, surface impedance, dynamic mass density, dynamic bulk modulus
• sound transmission loss
• impact sound level, attenuation of impact sound level
• quadratic velocities at front and rear side of respective building element (sending and receiving room)
• incident and radiated sound power (sending and receiving room)
• associated unique indicators (single-number values according to ISO 10140 series)

Excitation conditions

The vibro-acoustics software enables to select from various excitation conditions. These include:

• single plane sound wave incident from an arbitrary angle
• diffuse sound field (statistical sound incidence)
• one- and two-dimensional modal sound field
• single mechanical force
• impact sound of tapping machine
• rain-on-the-roof excitation
• turbulent boundary layer

Available calculation models

A large number of calculation models are provided by the vibro-acoustics software, e. g.:

• porous materials
  • fibrous: Delany-Bazley, Delany-Bazley-Miki, Attenborough
  • granular: Horoshenkov-Pore Size Distribution, Hamet
  • fibrous, cellular: JCA, JCAL, JCAPL, Miki, Wilson
  • imported measured data

• perforated plates/fabrics
  • circular, square, slit perforated plates
  • screens, woven/non-woven fabrics

• solid materials
  • elastic isotropic
  • visco-elastic isotropic: frequency-dependent values of Young’s modulus, Poisson ratio and damping loss factor
  • septum
  • impervious screen
  • limp and rigid bodies
  • orthotropic 3D
  • transverse isotropic
  • thin orthotropic plate

• heterogeneous materials
  • double porosity materials, porous composites
  • stud for double leaf partitions (point or line connection)
  • porous media with inner resonators

The majority of calculation models has been extensively validated by comparing calulation results of vibroacoustic characteristic values of the software AlphaCell with results of measurements in the test setup or numerical simulations.

Other general features

• spatial windowing according to Vigran, Rhazi and Ghinet methods
• assistant feature to help the interpretation of the results
• project based organization
• extended material data base (building, industry, automotive, aeronautics)
• possibility to import data for comparison (recomputation of associated unique indicators if applicable)
• export of materials to OptiStruct, Actran and Nastran format
• automated generation of report in Pdf format
• import of arbitrary file format for comparison purposes

Design, consultancy and seminars

From the development, over the evaluation, up to the optimization of sound absorbers as well as separating sound insulating building elements, we like to provide our specific technical knowledge. For that purpose, besides a training of your staff members regarding the handling of the vibro-acoustics software AlphaCell, we offer you various seminars and trainings courses in the field of technical acoustics.

Furthermore, on request, we support you with the acoustic design and the evaluation of sound absorbers as well as separating sound insulating building elements with respect to various applications. This includes especially the utilization in the area of building and room acoustics as well as noise reduction in terms of mufflers and silencers, noise screens and enclosures.

^{* AlphaCell is a trademark of the company MATELYS
** OptiStruct is a trademark of the company Altair
*** Actran and Nastran are trademarks of the MSC Software Corporation}