Purpose. Ensuring the determination of the basis weight of the textile fiber mass directly during the manufacturing process using an ultrasonic device equipped with non-contact ultrasonic sensors. In particular, show the effect of the basis weight of a textile fiber mass on the amplitude of probing vibrations in the measuring channel of an ultrasonic device. An amplitude control method is proposed, which is the basis of the operation of the ultrasonic device. It consists in irradiating the textile fiber mass, which moves relative to the scanning bracket with the sensors, and determining the basis weight of the fiber mass by reducing the amplitude of the ultrasonic waves in the measuring channel. The measurement results are processed with their subsequent digitization and computer analysis. It has been established that due to the passage and re-reflection of ultrasonic waves, which fall on two receivers with different vibration delays, it is possible to increase the accuracy of measurements of the average values of the basis weight of the textile fiber mass. Originality. In the general case, it is established that by passing and reflecting ultrasonic waves entering two receivers with different delay of oscillations, it is possible to increase the accuracy of measurements of average values of basis weight of textile fiber mass. The block diagram of the ultrasonic device for determination of basis weight of textile fiber mass is shown and its work is described. The main dependences on which the device system will determine the basis weight of the textile fiber mass are also given.

Two main methods employed in designing knitted fabrics for production rely on a given surface density or on the basis weight (grams per square meter). The actual value of these parameters may differ. Normally, the actual basis weight of knitted fabrics is determined by weighing a sample of a certain width and length and subsequently performing the relevant conversion (ISO 3801:1977). This method involves a destruction or wasting of the material. A non-destructive ultrasonic method for determining the basis weight of textile materials was developed, which is based on a determination of the amplitude ratio of ultrasonic waves falling on the fabric and the waves passing through it. However, this method has limitations in determining the basis weight of textile materials with variable porosity, such as knitted fabrics. To improve the developed method, it is proposed to continue the measuring of an amplitude of the reflected wave from the fabric surface. In this case, it is possible to monitor the fabric porosity changes. If the distance and pore size of the controlled fabric have increased or decreased relative to the control sample, the amplitude and magnitude of the reflected wave (part of the reflected ultrasonic signal) changes and the ultrasonic device will be adapted to the fabric structure. Our studies have demonstrated the possibility of determining the fabric porosity by using an amplitude of the reflected ultrasonic wave from the fabric surface, which allows adaptively to determine the basis weight using an amplitude of transmitted ultrasonic wave. Further development of ultrasonic non-contact methods and relative devises is very important for production control.

Research of attenuation of ultrasonic waves in various single-layer materials with available pores of different sizes changes in this work. The above is necessary for the possibility of creating non-contact means of ultrasonic testing of such materials. In the work to analyze the processes of interaction of ultrasonic waves with single-layer materials and various changes depending on the thickness or basis weight of the material. Expressions are given for the modules of the complex coefficient of transmission and reflection of ultrasonic waves from single-layer materials with small pores, as well as from textile single-layer materials with through pores, through which most of the vibrations pass. The dependences of relative changes in the amplitude attenuation of waves on the oscillation frequency, thickness and basis weight of the material are given. It is shown that the attenuation of the amplitude of ultrasonic waves that interact with single-layer materials with small pores, and the damping of vibrations for single-layer textile fabrics can be very different from each other. This difference is caused by the bending of part of the sound waves of the fibers of textile fabrics with through pores during the interaction of vibrations. The dependences of the relative changes in the difference of the modules with and without attenuation are obtained for the complex reflection and transmission coefficients of ultrasonic waves. These vibrations interacting with single-layer materials with different pores are considered taking into account the frequency of ultrasonic waves, pore sizes, thickness or basis weight of the material itself. The obtained dependences for determining the attenuation of the amplitude of the probe ultrasonic waves on the structure, porosity of the material, its thickness or surface density. This will allow to create non-contact control tools for materials with complex internal structures and automatically configure them to change pore sizes, which can significantly affect the errors of such devices. The accuracy of the devices that will be tuned to the complex structure of the monolayer material being controlled will be affected precisely by the attenuation parameter of the probe oscillations. In the future, this line of research will make it possible to create non-contact methods and means of monitoring the technological parameters of various single-layer materials and integrate such devices and systems directly into the production process.

The paper demonstrates the importance of controlling the surface density of textiles, which include mainly fabrics, knitted fabrics and nonwoven fabrics, in order to improve the quality of their manufacture. It considers the most accurate methods of controlling surface density by determining the mass to area ratio of the textile sample. And it is also shown that, in addition to high accuracy, such met­hods have many fundamental disadvantages: the need to obtain a sample of textile material, low productivity, inability to automate the process of determining surface density, and so on. In addition, it deals with optical methods for controlling surface density based on the imaging of textile material and its subsequent analysis. However, the presence of factors such as entanglement complexity, the presence of pores, and some others does not fully reveal the potential of optical surface density methods. The paper also shows that at different points in the surface of the textile material, its surface density may differ significantly from its average value. Therefore, there is a need for an automated scanning system that allows radiating and receiving electroacoustic converters to be moved to exactly the point of the surface of the textile material whose surface density requires measurement. In order to solve the problem, it was proposed to use a toothed belt gear, and to drive it with the help of step motors controlled through drivers. In turn, to communicate drivers with the control computer, it was proposed to use a microcontroller with an integrated USB interface (for example, manufactured by Microchip Technology Inc.), and software for it to write in one of the high- level programming languages (for example, C #). This construction of the automated scanning system is due to the fact that the existing means of linear movement, in terms of the design of the scanning system, have a lot of redundancy: too much cost, too much accuracy, the need to use specialized software, and so on. The use of the proposed linear positioning means will allow the scanning system to have sufficiently high metrological characteristics at a relatively low cost.

In article the possibility of definition (assessment) of thickness of a layer (defect) in materials with complex internal structure is considered.It is reached by application of acoustic non-contact control on the basis of the measured value of phase shift between packages of acoustic vibrations which were reflected from «reference» material without layer (defect) and from «interlayer» material with a layer (defect). Control of «reference» materialis shownin fig. 1. As it is possible to see, the coefficient of reflection of a package of acoustic vibrations in this case is defined by a formula (1). Control of «interlayer» material is shown in fig. 2. As it is also possible to see, the coefficient of reflection of a pac­kage of acoustic vibrations in this case is defined by a formula (9). Other value of coefficient of reflection is connected with additi­onal interaction of a package of acoustic vibrations and a layer (defect). As these two coefficients of reflection have different values, between them there is a phase shift determined by a formula (18). Having values of all known parameters of material with complex internal structure, except thickness of a layer (defect), using a formula (18) and other formulas accompanying her, it is possible to define or at least to estimate thickness of a layer (defect).The offered improvement of acoustic non-contact control can be useful also at control of properties of textile materials.