Comparison of methods for the estimation of Young’s moduli and structural loss factor of wood, applied to guitar soundboards made of Adirondack spruce

Standardised methods for characterising the mechanical properties of materials were mainly developed for metals or alloys with isotropic behaviour. They are consequently poorly suited to characterising materials that exhibit orthotropic and space-varying behaviour, such as polymers, composites, and natural materials like wood. The focus of this work is on guitar soundboards made of Adirondack spruce ( Picea rubens , also known as red spruce). Tests are conducted on 12 quarter-sawn plates. This work compares the practicality of methods to estimate the Young's modulus and the structural loss factor of these soundboards, while the variability of results for each method is outlined. A first interest of this work is to determine the trade-off between measurement methods and systems of variable cost and complexity. In addition, the viability of an asymptotic method is demonstrated for such structures (a technique based on mobility measurement and the assumption of an infinite structure). At the same time, the importance of considering the sensor mass is confirmed for low-density structures by comparison with measurements on aluminum and medium-density fibre board panels.