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Study for Contactless Detection of Number of Thin Sheet Material by Sound

声音非接触检测薄片材料数量的研究

基本信息

批准号：
16560205
负责人：
SAKAMOTO Shuichi
金额：
$ 2.18万
依托单位：
Niigata University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16560205/
关键词：
Sound Sensor Measurement Porous Thin film Number of sheet Non-contact

项目摘要

This report deals with the development of a new method for detecting the number of thin sheets of porous material without making contact. It is necessary to detect one or more of sheets to avoid mishandling. This detecting sensor utilizes the variation of the phase or magnitude of the transfer function within an entire acoustic system. The incident impedance of the porous material varies with the number of sheets. Characteristic acoustic impedance and complex wave number define the particular characteristics of the material. In this application it is useful to know characteristic impedance of the porous material. The measured impedance of sheets by the transfer function method was included in the theoretical analysis and FEM analysis. The results of the experiments, theoretical analysis and FEM show good coincidence.In the next part, the normal incidence absorption coefficient for porous multilayer between different grain diameters with arbitrary layer thicknesses can be calculated. This calculation process is comparatively lengthy, so the experiments for real multilayer and the calculations were compared. Result of the calculations agreed to the experiments. Consequently, calculation result of normal incidence absorption coefficient for multilayer between different grain diameters is useful.Moisture is an important affector for acoustic characteristics of the porous materials. So we investigated also about relationship between percentage of moisture content and absorption coefficient of granular (as porous) material.In the last research period we developed a system including an impedance tube with 4 microphones to measure transmission loss of porous thin film.

本文介绍了一种非接触式检测多孔材料薄片个数的新方法。有必要检测一张或多张纸，以避免误操作。该检测传感器利用整个声学系统内的传递函数的相位或幅度的变化。多孔材料的入射阻抗随片数而变化。特性声阻抗和复波数定义了材料的特定特性。在这种应用中，了解多孔材料的特性阻抗是有用的。理论分析和有限元分析均采用传递函数法测量了薄板的阻抗。实验结果、理论分析和有限元计算结果吻合较好。在接下来的部分中，可以计算任意层厚、不同粒径多孔多层膜的垂直入射吸收系数。由于计算过程较长，因此对真实的多层膜进行了实验研究，并与计算结果进行了比较。计算结果与实验结果一致。因此，不同粒径的多层吸声材料的垂直入射吸声系数的计算结果是有用的。因此，我们也研究了含水率和颗粒（如多孔）材料的吸收系数之间的关系。在最后的研究阶段，我们开发了一个系统，包括一个阻抗管与4个麦克风测量多孔薄膜的传输损耗。