EFFECTS OF ANYSOTROPY OF WOOD ON MODAL ANALYSIS OF VIOLIN PLATES

Abstract

Numerous studies concerning the acoustical behavior of violins refer to the similarities and differences in the tonal qualities produced by old and new instruments, depending on various factors. Among these factors the acoustical characteristics of wood species are criteria for the selection of the most appropriated raw material for violin making. The main wood species used in violin construction are spruce (Picea abies) and maple (Acer pseudoplatanus). In this paper, the violin plates were modeled with finite elements analysis based on three hypotheses – the material is isotropic; the material is transverse isotropic; the material is orthotropic, was used for modal analysis of violin plates. The plates were considered flat and having uniform thickness of 3 mm. The patterns of vibration modes are affected by wood species and structure. Spruce plate shows nodal lines aligned to L anisotropic direction of wood, corresponding with the direction of the fibres. Maple plates show nodal lines aligned to R anisotropic direction of wood and to the direction of medullary rays in the LR plane.