The influence of wood modification on transfer function of a violin bridge

Merhar, Miran (author), Humar, Miha (author)

The violin bridge is an important component of a violin since it transmits the excitation forces from the string to the violin body. Depending on its structure, at a certain frequency spectrum, the bridge acts as a damper or amplifier of excitation forces, which depends on its transfer function. In the study, transfer functions in the range from 400 Hz to 7000 Hz in vertical directions of 3 bridges were measured. The bridges were made from maple wood and supplied by different manufacturers. The bridges were then thermally modified, and the transfer functions were measured again. To determine the influence of thermal modification on material properties, a sample of maple wood was also modified together with the bridges, and the modulus of elasticity and shear modulus before and after the modification were measured. Using Ansys software, a bridge was modelled by the finite element method, by which natural frequencies and transfer functions before and after the modification were calculated. It can be confirmed from the research that wood modification influences the bridge transfer function and that the finite element method can be used to determine the dynamic properties of the bridge by knowing the wood material properties and, therefore, to predetermine the transfer function of the violin bridge before its production.

• Language: English
• Keywords: violin bridge, excitation, transfer function, finite element method, Ansys, wood modification
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: Str. 163-169
• Numbering: Vol. 71, iss. 2
• PID: 20.500.12556/RUL-117120
• UDC: 630* 8
• ISSN on article: 0012-6772
• DOI: 10.5552/drvind.2020.1966
• COBISS.SI-ID: 19835139
• Publication date in RUL: 24.06.2020

Record is a part of a journal

• Title: Drvna industrija : Znanstveno stručni časopis za pitanja drvne tehnologije
• Shortened title: Drv. ind.
• Publisher: Šumarski fakultet Sveučilišta u Zagrebu, Hrvatsko šumarsko društvo, Croatiadrvo, d. d., Exportdrvo, p. o.
• ISSN: 0012-6772
• COBISS.SI-ID: 2858754

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 28.04.2020

Secondary language

• Language: Croatian
• Title: Utjecaj modifikacije drva na prijenosnu funkciju mosta za violinu

Abstract

Most na violini važan je dio toga glazbala jer prenosi pobudne sile iz žica u tijelo violine. Ovisno o svojoj strukturi, most na određenome frekvencijskom spektru djeluje kao prigušivač ili kao pojačalo pobudnih sila, što ovisi o njegovoj prijenosnoj funkciji. U istraživanju su mjerene prijenosne funkcije u rasponu od 400 do 7000 Hz u okomitim smjerovima na tri mosta. Mostove od javorova drva izradili su različitih proizvođači. Naknadno su mostovi toplinski modificirani i ponovo su izmjerene njihove funkcije prijenosa. Da bi se utvrdio utjecaj toplinske modifikacije na svojstva materijala, zajedno s mostovima modificiran je i uzorak javorova drva te su izmjereni modul elastičnosti i modul smicanja prije i nakon modifikacije. Uz upotrebu softvera Ansys most je modeliran metodom konačnih elemenata, kojom su izračunane prirodne frekvencije i funkcije prijenosa prije i nakon modi- fikacije. Na temelju istraživanja može se potvrditi da modifikacija drva utječe na funkciju prijenosa mosta i da se metodom konačnih elemenata mogu odrediti dinamička svojstva mosta ako su poznata svojstva drvnog materijala. Prema tome, prijenosna funkcija mosta violine može se odrediti unaprijed, prije njegove izrade.

• Keywords: violinski most, vzbujanje, prenosna funkcija, metoda končnih elementov, Ansys, modifikacija lesa

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0182
• Name: Razvojna vrednotenja

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0015
• Name: Les in lignocelulozni kompoziti