Material model of thermally modified resonance spruce (Picea abies Karst.) for linear damped modal analysis

Abstract

ABSTRACT Finite element analysis (FEA) was used in this research to determine the dynamic behaviour of thermally modified Norway spruce (Picea abies Karst.). Damped modal analysis was selected for this purpose. Data obtained from non-destructive experimental work and from the literature provided input for modal analysis. The material characteristics were optimised and validated by experimental measurement; then the validated material model was mathematically described and FEA was applied. This work resulted in a generally validated material model of modified spruce based on material constants at various modification temperatures and humidities. Good agreement with a relative error of up to 7.1% was found between the numerical model and the experimental data. It was found that thermal modification caused an increase in resonance frequencies and higher humidity caused a decrease. The data provided and the model could prove useful for the non-destructive evaluation of thermally modified spruce and for predicting the behaviour of materials used in making musical instruments.