Wednesday, June 27, 2012
Eppes, Milanovic and DePanfilo Present Paper at Conference in France
The paper, "Resonance Modes in an Acoustic Guitar," describes the results of a finite element analysis of the eigen-modes of a Collings guitar, a well-known design developed and custom manufactured by Jim Collings. The paper describes a method to predict resonance patterns based on its physical shape and wood composition. Discrete modes, known as eigen-frequencies, denote where the amplitude responses of the acoustic chamber are the largest. Each mode represents a solution to an equation classically described as Helmholtz resonance. A 3-dimensional model was constructed using COMSOL Multiphysics for the geometry size/shape, a spruce soundboard and mahogany side/back walls. The analysis focuses on the lower end of the dynamic range from 200Hz to 1,000Hz in which surface deformation, both total and normal to the surface, are examined. In addition, node and anti-node structures in the area where the bridge attaches to the top plate are explored.