Project sponsor / Project executing agency

Trade Association for the Food and Hospitality Industry Mannheim/Erfurt

Project partner

Competence Center Interdisciplinary Prevention (KIP) Erfurt/Jena

Status

Funding status: approved

Duration: since 2004

Contact: Dipl.-Ing. Thomas Helbig

Project Description

 

Prevention research on noise-induced hearing loss in humans has been conducted as part of the Competence Center for Interdisciplinary Prevention of the Employer's Liability Insurance Association for Restaurants and Food since 2004, with changing thematic focuses. Current focal points are:

  • Examination of the anatomy of the external auditory canal

  • Investigation of the sound field around the outer ear depending on the geometry of the auditory canal by means of:

    • Finite element simulation and experimental setup

    • Experimental setup

  • Development of classified hearing protection systems

 

Investigation of the anatomy of the external auditory canal

The automated investigation of digital models of the auditory canal offers the possibility to make the large amount of data of polysiloxane ear impressions (typically several 100,000 data sets) available at individual hearing aid manufacturers scientifically usable. For this purpose, algorithms are developed at the Department of Biomechatronics for the (semi-)automatic analysis of the auditory canal models with regard to the determination:

  • the cross-sectional areas (area, length of the main axes of the elliptical cross-section, aspect ratio of the auditory canal cross-section) over the path length,

  • a mean path through the auditory canal,

  • and other auditory canal parameters

will be developed. After the creation of the required algorithms, the existing data sets of the auditory canal impressions are to be analyzed. The first step is to obtain more precise anatomical data regarding the cross-section and length of the auditory canal, as well as the characteristics of the "kinks" in the course of the auditory canal.

 

Finite element simulation of the sound field around the outer ear

Within the scope of the project, a model for the finite element simulation of the sound field around the outer ear was developed at the Department of Biomechatronics.

This model is used for the frequency-specific investigation of harmful noise influences in dependence:

  • interindividual auditory canal anatomies

  • the position of the eardrum

  • the angle of incidence of the sound

  • different hearing protection systems

 

Experimental setup

The development of an experimental or test stand according to the rules of the mechatronic design process according to VDI 2206 serves the purpose of

  • experimental investigation of the influence of the auditory canal geometry on the sound conduction to the eardrum (comparative investigations to finite element simulation) as well as

  • Functional testing of hearing protection systems with regard to attenuation and tightness

 

Development of classified hearing protection systems

By a precise, especially completely quantitative description of anatomical conditions of the auditory canal, it seems feasible to close the gap between simple earplugs and individually adapted earmoulds on the product side. A more precise sizing system for earplugs, taking into account the curvature of the auditory canal - not only the surface ratios - enables, after classification of the individual situation by a hearing aid acoustician, a significantly faster and more cost-effective supply of adequate personal noise protection.

 

Publications (exemplary)

Bances, Enrique; Schmidt, Tobias; Helbig, Thomas; Witte, Hartmut An ear-pinna acoustic analysis coupled with an ear-canal emulator 711. - In: Shaping the future by engineering / Ilmenau Scientific Colloquium. Ilmenau University of Technology ; 58 (Ilmenau) : 2014.09.08-12. - Ilmenau : Univ. Library, ilmedia (2014), 6 p. in all; nbn-resolving.de/urn:nbn:de:gbv:ilm1-2014iwk-159:6

Helbig, Thomas; Giese, Alexander; Kupper, Christoph; Witte, Hartmut; Schmidt, Tobias Parameters for automatic anatomical analysis of the external auditory canal. - In: Prevention of work-related health hazards and diseases / Erfurt days of the Berufsgenossenschaft Nahrungsmittel und Gaststätten ; 21 (Erfurt) : 2014.12.. - Jena : Bussert & Stadeler (2015), ISBN 978-3-942115-35-3, pp. 345-353.

Helbig, Thomas; Giese, Alexander; Bances, Enrique; Witte, Hartmut; Schmidt, Tobias Investigations on the anatomy of the auditory canal as a basis for classified hearing protection systems . - In: Prevention of work-related health hazards and diseases / Erfurt days of the Berufsgenossenschaft Nahrungsmittel und Gaststätten ; 21 (Erfurt) : 2014.12. - Jena : Bussert & Stadeler (2015), ISBN 978-3-942115-35-3, pp. 145-165.

Helbig, Thomas; Roland, Sophia; Bances, Enrique; Witte, HArtmut; Schmidt, Tobias Finite element investigations on the influence of different ear canal geometries on individual noise exposure. - In: Prevention of work-related health hazards and diseases / Erfurt days ; 22 (Erfurt) : 2015.12.03-05. - [Quedlinburg] : Verlag Bussert & Stadeler (2016), pp. 327-338.

Helbig, Thomas; Schmidt, Artjom; Roland, Sophia; Giese, Alexander; Finke, Tara Tanita; Schmidt, Tobias; Witte, Hartmut Characterizing the outer ear transfer function in dependence of interindividual differences of outer ear geometry. - In: Engineering for a changing world : 59th IWK, Ilmenau Scientific Colloquium, Ilmenau University of Technology, September 11-15, 2017 : proceedings. - Ilmenau : ilmedia / Ilmenau Scientific Colloquium. Ilmenau University of Technology ; 59 (Ilmenau) : 2017.09.11-15th, (2017), in total 7 pp. http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017iwk-029:4 Schmidt, Tobias; Helbig, Thomas; Kupper, Christoph; Witte, Hartmut A procedure for quantitative description of the anatomy of the ear canal - In: 108th Meeting of the Anatomical Society Magdeburg, Germany, Magdeburg (03/2013).

Sloma, Ulrike; Klein, Florian; Helbig, Thomas; Skowronek, Janto; Gadyuchko, Maria; Werner, Stephan; Breitbarth, Andreas; Neidhardt, Annika; Chillian, Antje; Brandenburg, Karlheinz; Raake, Alexander; Notni, Gunther; Sattel, Thomas; Witte, Hartmut; Husar, Peter GO-LEM - Characterization of Human Auditory and Auditory-Visual Perception in Everyday Scenes. - In: Prevention of work-related health hazards and diseases / Erfurt days ; 23 (Erfurt) : 2017.11.30-12.02. - [Jena : Verlag Bussert & Stadeler, ISBN 978-3-942115-45-2, (2017), pp. 349-356.

 

Student work

Finke, T. T. "Measurement of the physical effectiveness of hearing protection systems" (master thesis).

Giese, A. "Automated investigation of 3D models of the outer ear with respect to the cross-sectional area function of the auditory canal" (master thesis)

Götz, I. "Vibrating membranes in nature and technology" (bachelor thesis)

Hariri, R.: "Concepts for novel hearing protection systems" (bachelor thesis)

Helbig, T. "Automated positioning of measurement points on human eardrums" (diploma thesis)

Roland, S. "Extension of existing models for the determination of sound pressure distribution in the outer ear and auditory canal" (master thesis)

Schmidt, A. "Optimization of a model for measuring the physical effectiveness of hearing protection systems" (master thesis)

Schweitzer, D. "Methods for automated identification of anatomical landmarks in the middle ear" (master thesis)

Walter, J. "Optimization of a finite element model for the investigation of sound pressure distribution in the outer ear as a function of auditory canal geometry" (master thesis)

 

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