Effect of cross-sectional change of a board specimen on stress wave velocity determination
Effect of cross-sectional change of a board specimen on stress wave velocity determination
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DOI：
10.1515/hf.2005.036
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发表时间：
2005-02
期刊：
影响因子：
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通讯作者：
F. Divos;L. Dénes;Guillermo Íñiguez
中科院分区：
文献类型：
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作者：
F. Divos;L. Dénes;Guillermo Íñiguez
采用纵向应力波的无损评估 (NDE) 技术已在林产品工业中得到广泛应用。它们已被证明是评估测井特征的非常有效的方法（Bucur 1995）。基本上，这些评估基于振动方法来估计原木中纵向应力波的速度，从而确定工件的质量。该过程的准确性很高。应考虑一个重要问题：该理论基于沿样本长度的均匀横截面积。对于原木样本，原木两端的横截面积不同。这个问题针对原木的弯曲振动进行了详细研究（Sobue 1990）。本简短说明中描述的研究目的是研究不同面积比下纵向振动的横截面变化的影响。面积比（Ar）定义为较大横截面积与较小横截面积的比率。横截面变化对应力波速度的影响可以通过两种方式评估：使用有限元分析或通过实验。我们选择了第二种方法，并进行了大量的测试来评估这种现象。当使用纵向振动时，以下方程用于确定应力波速度：
Non-destructive evaluation (NDE) techniques employing longitudinal stress waves have been used in a variety of applications in the forest products industry. They have been shown to be very efficient methods in the assessment of log characterization (Bucur 1995). Basically, these evaluations estimate the velocity of the longitudinal stress waves in logs based on a vibration approach and thus determine the quality of the piece. The accuracy of the process is high. An important question should be taken into account: the theory is based on a uniform cross-sectional area along the length of the specimen. In the case of log specimens the cross-sectional area of the log is different at the two ends. This question was studied in detail for the flexural vibration of logs (Sobue 1990). The purpose of the research described in this short note was to investigate the effect of cross-section changes in longitudinal vibration for various area ratios. The area ratio (Ar) is defined as the ratio of the larger to the smaller cross-sectional area. The effect of cross-section changes on the stress wave velocity may be assessed in two ways: using finite element analysis or through experimentation. We chose the second approach, and carried out a large number of tests to assess this phenomenon. When using longitudinal vibrations, the following equation is used for stress-wave velocity determination: