## Abstract

Problems such as sound insulation and absorption of plane structures in laboratory conditions can

theoretically be described as an integral or integral-differential equation. This equation contains the Green’s

function integrated over the surface, which describes the radiation from the surface. A variational technique,

well described by Morse and Ingard, has successfully been used for both absorption and sound insulation for

a plane incident wave. The resulting formulas are surprisingly simple, accurate and robust. Moreover, they

capture the physics of sound radiation of a finite surface well. However, the approach has turned out

problematic in more complicated cases, including spatial periodicity. The paper discusses these issues, and

suggests modifications to overcome the problems.

theoretically be described as an integral or integral-differential equation. This equation contains the Green’s

function integrated over the surface, which describes the radiation from the surface. A variational technique,

well described by Morse and Ingard, has successfully been used for both absorption and sound insulation for

a plane incident wave. The resulting formulas are surprisingly simple, accurate and robust. Moreover, they

capture the physics of sound radiation of a finite surface well. However, the approach has turned out

problematic in more complicated cases, including spatial periodicity. The paper discusses these issues, and

suggests modifications to overcome the problems.

Original language | English |
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Title of host publication | Proceedings of Inter-noise |

Editors | Wolfgang Kropp |

Number of pages | 8 |

Publication date | 2016 |

ISBN (Electronic) | 978-3-939296-11-9 |

Publication status | Published - 2016 |

Event | 45th International Congress and Exposition on Noise Control Engineering - Hamburg, Germany Duration: 21 Aug 2016 → 24 Aug 2016 Conference number: 45 http://www.internoise2016.org/ |

### Conference

Conference | 45th International Congress and Exposition on Noise Control Engineering |
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Number | 45 |

Country/Territory | Germany |

City | Hamburg |

Period | 21/08/2016 → 24/08/2016 |

Internet address |

## Keywords

- Vibro-Acoustics
- Transmission, Absorption