罐裝液體食品黏度非破壞檢測系統的自由減振扭轉振動分析

Analysis of Damped Free Torsional Vibration of a Non-Destructive Viscosity Evaluation System For Canned Liquid Foods

李允中(Yeun-Chung Lee) ； 王峻禧(Chun-Shi Wang)

《農業機械學刊》 5卷4期 (1996/12) Pp. 47-55

https://doi.org/10.30062/JAM.199612.0005

摘要

自由扭轉振動系統的減振現象，可以用來測量罐頭內液體食品的黏度，以作為液體食品品質非破壞檢測的方法。前人曾以實驗方法探討這種應用，但缺乏理論的分析。本文將此測量裝置模擬為有液體減振器的自由減振扭轉振動系統，並以Navicr-Stokes方程式描述罐內流體的一維流動。經過合理的簡化得到數學模式的近似解，並用實驗數據得到驗證。黏度量測振動系統振幅的衰減係數，依照理論可以表示成轉動慣量、振動頻率、罐高、罐徑，以及罐內液體密度與黏度的函數。但在此研究範圍內的振動頻率，不隨上述變數改變，可能是實驗裝置彈簧的扭轉剛性較高。研究結果所得到的公式可以提供食品黏度非破壞量測設備設計的參考。

關鍵字

扭轉振動 ； 衰減係數 ； 非破壞測定 ； 數學模式 ； 罐裝液體食品

並列摘要

The damping effect of a free torsional vibration could be used to evaluate the viscosity of liquid food in a can, that could be applied in non-destructive quality tests. Some experimental studies on these applications have been done by other researchers, but with minimum theoretical considerations. In the study, the oscillatory tester was modeled mathematically as a damped free torsional vibration system coupled with a rotational viscous damper governed by an unidirectional Navier-Stokes equation. An approximate solution was obtained for the mathematical model; and the theoretical solution was successfully verified by experimental data. The damping coefficient of the oscillatory could be analytically described as a function of the torsion constant and the frequency of the osillatory tester, the radius and the height of can, also the density and the viscosity of liquid in the can. The frequency of the system studied were almost independent of all variables, and that could be a result of a high rotational stiffness of the testing device. The theoretical equation could provide a powerful tool for the design of a non-destructive testing apparatus for canned liquid food.

並列關鍵字

Torsional vibration ； Damping coefficient ； Non-destructive evaluation ； Mathematical model ； Canned liquid food