Bohdan H. Improvement of ultrasonic testing method of physical and mechanical characteristics of powder materials

The thesis is devoted to the problems of increasing the accuracy of measurement of physical and mechanical characteristics of powder structural materials with the help of acoustic methods of nondestructive testing and the development of a specialized system. The system based on the method of processing the results of measuring the velocity of an acoustic wave propagation in powdered structural materials that allows to reduce the influence of random factors on the testing result. The analysis of the existing methods for evaluating the physico-mechanical characteristics of powdered structural materials during the development of the production technology showed that in order to obtain an efficient production technology and optimize the initial composition component of the material, it is necessary to evaluate the changes in the physics-mechanical characteristics after each technological process. It is shown that the measurement error must be significantly reduced in order to detect the true variation in ultrasound velocity (both in batch and in individual samples made from multiphase powder materials) due to a change in technological manufacturing regimes. In the thesis, the factors that make a significant contribution to the total error formation in measuring the ultrasonic wave propagation velocity are considered. In the paper, techniques and methods are proposed to reduce their effect on the measurement result. They consist of the use of special blocks of primary converters, the system for mounting the transducer block on the surface of the monitoring object, and the use of special software that allows us to filter out the results with gross errors. The structural scheme, hardware and system design for the estimation of the change in physical and mechanical characteristics based on the results of acoustic nondestructive testing are developed. Reduction of the total error in measuring the propagation velocity of ultrasonic waves in powdered structural materials was received due to the complex application of automation of the obtaining measurement information process, statistical data processing methods, an improved orthogonal discrete phase method for measuring time delay, and a set of structural-parametric solutions. A technique is proposed for monitoring physical and mechanical parameters of powder structural materials based on the obtained results of the ultrasonic wave propagation velocity and the technique for development the technology for manufacturing powder structural materials based on the results of acoustic nondestructive testing.