ObjectiveIt is very necessary to find new materials to replace the traditional wood materials for sound boards in China because of the serious shortage of wood materials for sound boards in our country.

MethodIn this paper, birch veneer/glass fiber composites were prepared using glass fiber as reinforcement and birch veneer as matrix according to the structure design of veneer laminated building blocks. By testing and analyzing the acoustic and vibration properties of the composites, the effects of the placement position and the number of layers of glass fiber cloth on the acoustic and vibration properties of the composites were investigated.

ResultThe specific dynamic elastic modulus and E/G value of composite A with one layer of glass fiber cloth under the surface layer were 22.20GPa and 16.55, respectively, which were 8.7% and 17.8% higher than those of composite material B with one layer of glass fiber cloth at the center layer. The specific dynamic elastic modulus and E/G value of composite C with two layers of glass fiber cloth in the upper and lower layers were 25.04GPa and 17.04, respectively, which were 7.5% and 18% higher than those of composite material D with glass fiber cloth in the center layer. The placement of fiber had little effect on acoustic radiation quality constant and acoustic impedance. There were no linear relationships between the layers of glass fiber cloth and the acoustic vibration properties of the composites. The composites with two layers of glass fiber cloth had better specific dynamic elastic modulus and E/G value. The specific dynamic elastic modulus of the composites with three or four layers of glass fiber cloth was lower than that of the composites with two layers of glass fiber cloth. With the increase of the number of layers, the sound radiation quality constant decreased. Through the comprehensive coordinate analysis, it was found that the composite score of glass fiber cloth on the surface was higher than the central layer, and the composite score of two layers of glass fiber cloth reached the maximum.

ConclusionThe acoustic vibration properties of the composites with glass fiber cloth on the surface layer were better than those with glass fiber cloth on the center layer. The composite C with 2 layers of glass fiber cloth has the best acoustic vibration performance. Although the E/G value of composite C is about 80% of Picea sitchensis, the specific dynamic modulus of elasticity is similar to Picea sitchensis, indicating that the birch veneer/glass fiber composite has the possibility of being used as a wood substitute for musical instruments.