SEAlab

Applied Acoustics : Research : SEAlab

Last update Sept 5, 2011 by Patrik Andersson

General

SEAlab is a free Statistical Energy Analysis (SEA) code implemented in Matlab. It is an open source project where the Matlab-code (m-files) is open. See list below for validated cases and available subsystems and connections/junctions.

We hope that this code will be continuosly developed and updated in the future.

Feel free to make contributions to the code and/or to submit suggestions for improvements.

Contact: Patrik Andersson

History

2010: The SEAlab project idea is initiated by Lars Ivarsson (Semcon / A2Zound by Semcon) and Patrik Andersson (Applied Acoustics, Chalmers).

2010 June-December: Daniel Johansson and Peter Comnell implement a first version of the code in their Master's thesis project. They perform initial validations.

2011 April-June: Patrik Andersson debugs and expands the code. It is now possible to run the code without the (limited) graphical interface. Additional validations are made.

2011 June 8: The code is pusblished at this webpage (SEAlab version 0.0)

2011 Sept 5: SEAlab version 0.1 is published.

Documentation

Master's Thesis 2010, Daniel Johansson and Peter Comnell

Statistical Energy Analysis software: Development and implementation of an open source code in Matlab/Octave

This thesis contains

  • the structure of the code,
  • the struct-variable data... containing the input data and results, and
  • the theory behind the implementation with references.

Specific information for the SEAlab version 0.1 release:

SEAlab_v0p1_information.txt

Download SEAlab code

Username and password is required to download the SEAlab software. Send an e-mail to Patrik Andersson to get the username and password.

Download SEAlab version 0.1 (2n release Sept 5, 2011)

SEAlab version 0.1 Information

by Patrik Andersson Sept 5, 2011

Updates from version 0.0 to version 0.1

Corrected a bug that gave erroneous results for connected plates with different wave speed (e.g. different thickness, density and/or stiffness). The error was significant for plates connected with close to 180 deg angle.

File: tau_plate_plate.m

Added the SEAlab paths to the top of the path list instead of at the end, so

that files of the correct version is used.

File: enablepaths.m

Updated the predifined Young's modulus for 'Concrete'.

File: physicalproperties.mat

Getting started

It is now possible (and recommended) to run the software using text-based inputs that calls SEAlab_v0p1. Examples of input files are located in the input/-folder.

Example functions for plotting various results are found in the postprocessing/-folder.

New material data may be added using the function physicalproperties.m in the data/-folder.

To start the graphical interface type SEAlab in the command window. The graphical interface may be used but it is still under development so at lot of functionality is missing. For example, the menu commands cannot be used.

Tests and validation

The code has been tested and validated for the following cases:

  • single plate
  • multiple plates of different geometry and material connected at multiple junctions including with more than two plates in one junctions
  • single cavity
  • plate-cavity where the plate is excited and radiates into the cavity have been tested for different plates and dimensions the cavity
  • cavity-plate-cavity where one of the cavities is excited for different plates and cavities
  • cavity-plate-cavity-plate-cavity where one of the cavities is excited and the middle cavity and plates are constituting a double wall

Octave compatibility

The code has not yet been tested and updated to run in octave

(the plot functions will definitely not work)

Some important limitations

For connected plates all line junction CLFs are included, but not corner junction CLFs.

The integration scheme when calculating the diffuse transmission coefficients for plate to plate line junctions is rudimentary using predefined evaluation points for the trapezoidal integration scheme. The evaluation points are not adapted to the behaviour of the integrand that may have a step-like behaviour at the angle of on-set of transmission of certain wave types. This causes small errors in some of the CLFs of small magnitude (when there are a step in the integrand and few non-zero integrand values in the summation).

Double wall transmission

  • non-resonant transmission included:
  • mass law of each plate (room-plate-cavity, cavity-plate-room)
  • double wall transmission (room-plate-cavity-plate-room) using the engineering formula described in the thesis
  • non-resonant transmission NOT included:
  • non-resonant transmission (plate-cavity-plate-room)
  • the resonant transmission is included