云杉材纹理角度对钢琴音板声学振动性能的影响

Effect of Spruce Grain Angle on Acoustic Vibration Properties of Piano Soundboard

云杉材是制作钢琴音板的主要用材,以4种云杉属木材为研究对象,采用快速傅里叶变换分析法测试其共振频率,并计算其声学振动性能参数,分析木材纹理角度对云杉材声学振动性能具有的影响。结果表明:随着纹理角的增大,云杉材的动弹性模量、比动弹性模量增大,损耗角正切减小。当纹理角为90°时,云杉材的振动效率最高、声能损耗最少,声学性能最优。通过综合加权法评定,纹理角90°的麦吊云杉具有最优振动性能。

Spruce wood is one of the main materials for making piano soundboard.In order to understand effects of spruce grain angles on acoustic vibration properties of piano soundboard,four types of spruce species were selected and three grain angles of each spruce species were tested to measure the acoustic vibration properties by the Fast Fourier Transform analysis(FFT).Wood acoustic parameters tested were dynamic elastic modulus,specific elastic modulus,acoustic radiation damping coefficient and absorption coefficient as well as loss tangent.The testing results showed that most of the acoustic parameters of the wood samples increased but the loss tangent decreased with the increase of grain angles.The wood samples with 90°of grain angle presented the highest vibration efficiency and the lowest acoustic energy loss.According to a comprehensive weighting results,soundboard made of Picea brachytyla wood with 90°of grain angle showed the best vibration property.