轴向压缩载荷下的音板木材振动和声学响应特性研究

Vibration and acoustic response characteristics of soundboard wood under axial compressive load

为了探究轴向压缩载荷对音板木材的振动和声学响应特性的影响,深入研究木质材料的发声机理。本研究模拟音板木材在实际装配中受到的约束和轴向压缩载荷,利用双通道快速傅里叶变换(FFT)频谱分析仪对200~1600 N轴向压缩载荷作用下音板木材的振动和声学性能进行检测。分析发现:在弹性形变范围内,随着轴向压缩载荷的增大,木材的共振频率呈下降的变化规律;轴向压缩载荷与音板木材的各声学参数呈显著的线性相关。通过SEM扫描电镜观察发现,正常、通直的细胞壁由于轴向压缩出现不同程度的褶皱,这是音板木材振动和声学性能变化的重要原因。研究结果表明,轴向压缩载荷对音板木材的振动和声学性能的影响具有较强的规律性,因预应力的存在以及微观构造的改变,其整体振动和声学性能呈下降趋势。

Here,to explore effects of axial compression load on vibration and acoustic response characteristics of soundboard wood,the sound generating mechanism of wood materials was deeply studied.Constraints and axial compression load exerted on soundboard wood in actual assembly were simulated,and vibration and acoustic properties of soundboard wood under 200-1600 N axial compression load were detected with a dual-channel fast Fourier transform(FFT)spectrum analyzer.The analysis showed that the wood resonant frequency decreases with increase in axial compressive load within the range of elastic deformation;axial compression load and acoustic parameters of soundboard wood reveals significant linear correlation;SEM observation finds normal and straight cell walls have folds with different degrees due to axial compression,this is the important reason for variations of soundboard wood vibration and acoustic properties;effects of axial compression load on soundboard wood’s vibration and acoustic properties have stronger regularity;due to existence of prestress and change of microstructure,soundboard wood’s overall vibration and acoustic properties reveal a downward trend.