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.

该报告介绍了一种新方法的开发，该方法无需接触，用于检测多孔材料的薄片数量。有必要检测一张或多个床单，以避免不当。该检测传感器利用整个声学系统中传递函数的相位或幅度的变化。多孔材料的事件阻抗随板的数量而异。特征声阻抗和复杂的波数定义了材料的特定特征。在此应用中，了解多孔材料的特征阻抗是有用的。通过转移函数方法测得的纸张阻抗已包括在理论分析和FEM分析中。实验的结果，理论分析和FEM显示出良好的巧合。在下一部分中，可以计算出具有任意层厚度的不同晶粒直径之间多孔多层的正常发病率吸收系数。该计算过程相对较长，因此比较了实际多层的实验和计算。计算的结果同意实验。因此，不同晶粒直径之间多层的正常发病率吸收系数的计算结果很有用。因此，我们还研究了水分含量百分比与颗粒状（如多孔）材料的吸收系数之间的关系。在上一个研究期间，我们开发了一个系统，其中包括带有4个麦克风的阻抗管来测量多孔薄膜的传输损失。