REFLECTIONS OF ULTRASONIC WAVES FROM A TWO-LAYER PACKAGE OF TEXTILE MATERIALS WITH A DENSE FIRST LAYER

Abstract

Obtain and show in general terms the expression for the module of the complex reflection coefficient of ultrasonic waves from a two-layer package of textile materials with a dense first layer. The above is necessary for the possibility of research of contactless control of such materials. To analyze the process of reflection of waves from a controlled material, the method of superposition of sounding vibrations is used. In general terms, the expression for the complex reflection coefficient of ultrasonic waves from a two-layer package of textile materials with a dense first layer is shown. It is proved that taking into account the complete attenuation of the reflected waves in the layer of the first material, it is possible to simplify the basic expressions for the complex reflection coefficient from a package of textile materials. It is shown that the change in the amplitude of the reflected ultrasonic waves for the material presented in the work with a change in the thickness of its layers is very small. The change in the amplitude of the reflected waves for such materials mainly causes a dense first layer of package of textile materials. The dependences of the real and imaginary parts of the complex reflection coefficient of ultrasonic waves on a package of textile materials with a dense first layer are obtained, which will help analytically determine both the change in the amplitude of the waves and their phase shift caused by the interaction of these vibrations with the material. It is proposed to use the component expressions for the module of the complex reflection coefficient of ultrasonic waves, which will allow you to adjust the parameters of the contactless transducers for different two-layer package of textile materials with a dense surface layer. To ensure the possibility of determining a small change in the measured magnitude of the amplitude of the reflected ultrasonic waves from the two-layer package of textile materials with the first dense layer, you can use switching and modulation devices and transducers. This will eliminate the errors that may be associated with the non-identity of the measuring channels when determining a small change in the amplitude of the reflected ultrasonic waves.