Application of natural fiber composites to musical instrument top plates

A flax-reinforced sandwich structure suitable for replacing wood in the top plates of string musical instruments was developed. The mechanical properties of Sitka spruce, the most widely used wood species for this application, were taken as a benchmark when the new materials were developed. The materials were characterized by static and dynamic methods to determine the dynamic Young's modulus, shear modulus, internal friction, and static mechanical properties. Based on the material characterization, a hand lay-up process with a two-part closed mold and internal pressure bladder was developed and six prototype ukuleles were manufactured. The results show that the flax-reinforced sandwich structure can successfully act as a top plate and that an efficient manufacturing process can be developed to produce monocoque string musical instruments out of composite materials.