激光测振在盒装牛奶无损检测中的应用与实验研究

Application and Experimental Study of Laser Vibration Measurement in Boxed Milk Nondestructive Testing

为了解决盒装牛奶坏包的无损检测问题,从牛奶变质过程中流变学特征即粘度变化的角度出发,建立了盒装牛奶随机激励下的振动系统动力学模型,分析了牛奶粘度和振动系统阻尼比之间的关系,采用二维激光测振系统设计了基于动力学参数测量的牛奶无损检测装置,通过分析随机激励下的液态奶的振荡特性,研究了牛奶变质前后不同粘度下,系统阻尼比的变化,实验研究表明,相比较未变质时,盒装牛奶变质后,粘度增加了67.7%,阻尼比增加了152.6%,系统的阻尼比有明显增加,其量值对牛奶质量的变化反应更敏感,采用盒装牛奶阻尼比判别域对牛奶品质实现无损检测的方法经济方便,灵敏度较高,可用于盒装乳品的质量检验及质量控制。

In order to solve the problem of nondestructive testing of boxed milk spoilage, starting from the perspective of rheo- logical characteristics of the milk during the deterioration process, the dynamic model of the vibration system of the boxed milk under random excitation was established, and the relationship between the milk viscosity and the damping ratio of the vibration system is analyzed. The two dimensional laser vibration measuring system is used to design a milk nondestructive testing device based on the kinetic parameters measurement. By analyzing the oscillation characteristics of liquid milk under random excita tion, the change of damping ratio of the system under different viscosities before and after milk deterioration was studied. The experimental results showed that, compared with no deterioration, the viscosity of the boxed milk increased by 67.7%and the damping ratio increased by 152.6% after the milk was bad, and the damping ratio of the system increased obviously, and its value was more sensitive to the change of milk quality. The method of nondestructive testing of the milk quality by building the milk quality damping ratio discriminant domain is economical, convenient and sensitive and it can be used for the quality inspec tion and quality control of the boxed dairy products.