Seismic Wave Field Model Excited by a Finite Long Cylindrical Charge

The amplitude-frequency characteristic of a seismic wave excited by explosion sources directly affects the accuracy of seismic exploration. To reveal the effect law related to a cylindrical charge, the research proposes a seismic wavefield model excited by a long cylindrical charge. According to the characteristics of the blasting cavity generated by a finite length cylindrical charge, the seismic wavefield characteristics of a cylindrical charge excitation is obtained by superposing the seismic wavefield excited by a series of spherical charges. Numerical simulation results show that the calculation error of the blasting cavity characteristics of the theoretical model is within 10%. The comparison with field experimental results shows that the error of the model is within 9.4%. The velocity field of the excited seismic wave is almost the same as that of the spherical charge when the explosion distance to the cylindrical charge with finite length is 16-21 times longer than the charge length, but the frequency of the seismic wave is 30% higher than for a spherical charge. Moreover, the explosive velocity has a certain influence on the amplitude-frequency characteristic of the seismic wave excited by the cylindrical charge. The established theoretical model can accurately describe the amplitude-frequency characteristics of the seismic wavefield excited by a cylindrical charge with finite length.

Нелинейное расщепление линии магнитоупругого резонанса в сильно возбужденном феррите

The nonlinear splitting of magnetoelastic resonance line in powerfully excited ferrite is investigated. It is shown that the amplitude of splited resonance has the same order of value that the amplitude of basis resonance and its frequency is determined by the upper boundary of nonlinear amplitude-frequency characteristic of magnetic system. It is found the threshold character of splitting additional resonance from general. It is determined the possibility of operation of splited elastic resonance frequency by changing of exited magnetic field value which has practical importance.

ALGORITHM FOR DETERMINATION OF RELIABILITY INDICATOR OF GAS GENERATOR OF HYDROGEN STORAGE AND SUPPLY SYSTEM

An algorithm for determining one of the indicators of reliability of the main element of the hydrogen storage and supply system – a gas generator has been developed. Such an algorithm is an integral part of the general algorithm to ensure the required level of fire safety of hydrogen storage and supply systems. The algorithm involves the implementation of several stages. At the first stage, using the expression for the amplitude-frequency characteristic of the gas generator, the functional dependences for its time constants are obtained. These functional dependencies include the values of the transmission coefficient and amplitude-frequency characteristics, which are determined at three a priori set values of frequency. In the second stage, the amplitude-frequency characteristic of the gas generator is determined. For this purpose, an array of data is used, which characterizes the reaction of the gas generator to the test effect in the form of an abrupt change in the area of its outlet. The amplitude-frequency characteristic of the gas generator is determined numerically, and its parameters are the increase in the pressure in the cavity of the gas generator and the time interval at which this increase is determined. The Kotelnikov-Nyquist-Shannon theorem is used to determine this time interval. At the third stage, the probability of the values of the time constants of the gas generator outside the tolerance zone is determined. For this purpose, models of gas generator time constants and their metrological characteristics are used. In the fourth stage, the probability of failure of the gas generator is determined, for which the information of the previous stage is used. At the last stage, the algorithm for determining the probability of failure of the gas generator of the storage and supply system of hydrogen, which is given in verbal form.

JUSTIFICATION OF THE METHOD OF DETERMINATION OF THE CONSTANT TIME OF THE GAS GENERATOR OF THE SYSTEM OF STORAGE AND SUPPLY OF HYDROGEN

The method of determining the dynamic parameter - the time constant of the gas generator of the storage and supply of hydrogen on the basis of the hydro-reactive composition is substantiated. The method is based on the use of the amplitude-frequency characteristics of the gas generator of the storage and supply system of hydrogen. The method involves the implementation of three stages. At the first stage, the mathematical dependence of the gas generator time constant on its static parameter and amplitude-frequency characteristic at a fixed frequency is obtained. In the second stage, the choice of this fixed frequency is justified. This dependence includes the value of the amplitude-frequency characteristic of the gas generator of the storage and supply of hydrogen at a fixed frequency, the static parameter of such a gas generator – its transmission coefficient, and the value of the fixed frequency. In the second stage, the choice of this fixed frequency is justified. This choice is made provided that the minimum error in determining the time constant of the gas generator. To determine the static parameter of the gas generator and the value of its amplitude-frequency characteristic at a fixed frequency, an array of data is used, which is formed by measuring the values ​​of the transient function of the gas generator through equal moments of time. These time intervals are chosen according to the Kotelnikov-Nyquist-Shannon theorem. The amplitude-frequency characteristic of the gas generator of the hydrogen storage and supply system is determined numerically. According to the research results, an iterative procedure for determining the time constant of the gas generator of the hydrogen storage and supply system is given. Recommendations for using this procedure are given. The choice of the time constant of the gas generator of the hydrogen storage and supply system is made using the tolerance criterion.

Selecting the Proportional-Integral (PI) Regulator Parameters from the Condition of Maximum Permissible Deviation in Leap Impacts on the System

The amplitude-frequency characteristic, which determines the parameters of the PI controller for linear objects, is either a monotonically feeding function, or has one resonant peak, and practically does not have a drop at a frequency less than the resonant one. The parameters of the PI controller selected in this way ensure, that the maximum deviation of the controlled value does not exceed the set value when stepping on the input of the object.

Machining technology of shaft parts based on CAD technology

With the continuous development of manufacturing industry, the requirements of process design with system intelligence and informatization are higher and higher. Traditional manual technology can not meet the modern requirements, modern intelligent computer-aided process design is more and more widely used. The purpose of this study is to use CAD technology with process shaft technology. In this study, different radii of shaft components were selected and horizontal tensions of 600 kN and 1200 kN were applied to test their effects and efficiency. We compared the processing efficiency and accuracy of conventional manual processing technology and computer-assisted design. In this study, a parametric process planning template with constraint knowledge is established for each part group and stored in the process planning template library. A parametric process plan was derived using the 3d model and the feature parameters extracted from the specific manufacturing environment knowledge base. The results show that the amplitude frequency characteristic of the whole workpiece increases first and then decreases from the chuck to the tip, and the amplitude frequency characteristic amplitude is the largest at the distance of 3/4 from the chuck. The maximum value appears at 174.47Hz and the amplitude is 0.000427N/mm. Compared with manual machining, the machining time of CAD machining mode is reduced by 22.94%, the metal removal rate is increased by 34%, and the cutting efficiency is significantly improved. It is concluded that the computer-aided design technology in this study plays a more accurate and time-saving role in the processing of shaft parts and contributes to the intelligent part processing.

Longitudinal vibrations of a cylindrical bar from the action of harmonic forces

The longitudinal vibration of a cylindrical rod has been studied in an elastic medium from the action of axial harmonic forces in a state of compression tension. The consideration took into account the damping of vibration of the rod according to the theory of E.S. Sorokin. Taking into account, internal friction made it possible to approach the real state of the rod as a source of wave radiation. The amplitude-frequency characteristic of the structure is built, taking into account changes in the parameters of the environment and the rod. The possibilities of the emergence of the resonance state of the rod are established. At the same time, cases were considered with and without inelastic properties of the rod material. The analysis of the influence of the properties of the environment and the rod on the amplitude of the displacement of the latter is carried out.