木材动态弹性模量测量中节子对于应力波传播的影响

为了探讨振动法测量木材动态弹性模量时应力波波速的差异性，以油松、马尾松和杉木的锯材为试验材料，通过横向振动测量与纵向敲击法测量，研究其节子对木材应力波传播速度和弹性模量的影响。结果表明:随着节子质量的增大，引起纵向振动频率减小，应力波波速减小；在节子总质量不变的情形下，节子数量越多，应力波波速也越小；节子尺寸大小与应力波波速成反比，节子质量越大，应力波波速越小。木材节子影响了应力波波速及弹性模量，也影响了木材自身的品质。

Influence of Wood Knots on the Stress Wave Propagation in the Dynamic Measurement of Elastic Modulus

In order to understand the differences of stress wave velocity in the measurement of wood dynamic elastic modulus,we selected the sawn timber of Chinese pine,Chinese red pine and fir as materials to examine the influences of the knots in the timber on the stress wave velocity through lateral and vertical measurements. The results showed that with the increase of the knot mass,longitudinal vibration frequency and stress wave velocity decreased.Under fixed total knot mass,the greater the number of knots,the smaller stress wave velocity was.The knot size was negatively correlated with the stress wave velocity,and the knot mass was inversely proportional to the stress wave velocity.Knots in the timber affect stress wave velocity and elastic modulus,and also affect the quality of the wood itself.