Papers by Keyword: Oscillations

Abstract: The paper presents the results of the study of bodies movement on a rough surface, which carries out longitudinal and transverse oscillations. The design of the inertial conveyor for reducing dynamic loads has been proposed. The dependences of the acceleration of the longitudinal oscillations of the chute and the speed of the transverse oscillations of the chute walls on dimensionless time τ=ωt have been obtained. As a result of the kinematic analysis of the mechanism of the reciprocating movement of the chute, the dependences of the movement, speed and acceleration of the chute of the inertial conveyor on the angle of rotation of the crank and its rotation frequency have been obtained. As a result of the conducted theoretical studies, it has established that when the chute of the inertial conveyor is given transverse oscillations during periods of time and when the load slides along the surface of the chute, the productivity of this vehicle significantly increases. The obtained dependencies can be used in the design of inertial conveyors with given technical and economic indicators.

Abstract: The result of the research aims to provide a foundation structure that reduces the amplitude of oscillation of machines and equipment from various technical causes and natural phenomena, preventing resonant phenomena and economical use of foundation material. The proposed foundation, compared to existing foundations, provides a decrease in amplitude and prevents the phenomenon of resonance of vibrations of foundations for machines and equipment creating savings in the use of cement-concrete material. There is considered mathematical, structural, and practical modeling of anti-vibration foundations of mechanical installations in this article. The purpose of the study is to create a foundation design that reduces the amplitude of oscillation of structures from various technical reasons and natural phenomena, prevents resonant phenomena, and economical use of foundation-reinforced concrete material. The research results can be used in the design of foundations of piston machines and equipment used in the oil and gas industry.

Abstract: The relationship of oscillations amplitude of the granular medium-elastic screw system whilst passing over resonance at different values of the bulk mass per unit length at different motion velocity has been studied. The relation of resonance oscillations of the granular medium-elastic screw system described by ratio α(t) and ν(t) has been shown. Based on these ratios, we plotted time variations of amplitude against quick passing over resonance.

Abstract: In the work the problem of complicating engineering structures and structures is raised, which in turn increases their vulnerability to natural phenomena. Each structure has some probability of destruction, an attempt to bring this probability to zero is accompanied by a rapid increase in its value. In addition, structures cannot be completely free from the risk of destruction due to uncertainties in the requirements for the system, the spread of the technical properties of building materials, the difficulties in adequately modeling the behavior of the system even with the use of modern software systems. The need to take into account the frequency composition of technogenic earthquakes which will allow to perform the necessary protection of structures that are particularly long-lasting from the resonance effect is considered and justified.

Abstract: The authors analyze the dynamical and geometrical aspects regarding the behaviour of a locomotive running on curved routes . There were taken into account all the possible disturbing effects and all the forces and torques acting on the bogie frame and on the coaches or carriages. A sophisticated calculus model is proposed for the analytic investigation. The guidance and the vertical forces on the wheel, the derailment criterion and the spring vibration damping are the main subjects of the investigation.

Abstract: A first model developed by the authors for the study of pathological oscillations in Parkinson's disease is reviewed. This provides conditions for onset and extinction of almost sinusoidal oscillations. The describing function approach for use in such a situation is introduced and it is shown that the two describing functions used here may be “composed” into a single equivalent describing function. Conditions at onset or quenching of oscillation are noted, but wider applications have yet to be developed.

Abstract: The present work deals with investigation of features of a magnetization vector of nonlinear precession and elastic displacements close to ferromagnetic resonance in normal magnetized ferrite plate. The system of ordinary differential equations was solved numerically by the Runge-Kutta 7-8 orders method with control of the integration at every step length. The possible excitation of magnetoelastic autooscillations was found out in the paper. Two mechanisms of autooscillations: reorientation and detuning were investigated. The boundaries between the regular and chaotic reorientation autooscillations depending on the magnetic dissipation parameter and magnetoelastic interaction constant were determined.

Abstract: New technologies of reinforcement works have been developed. The results of studies have been recommended to be applied in engineering methods to calculate manufacturing of reinforcement units. Oscillation cutting has been theoretically grounded, the physical nature and process of oscillation cutting and shaping have been studied.

Abstract: Using ABAQUS to analyze the response of tall building under expected rare earthquake, usually the gravity field can be derived by the implicit method as the initial condition of simulation for seismic wave executed in the explicit method. In practice of engineering, oscillation of gravity often occurred at the beginning of explicit method which would lowered accuracy and reliability of time-history results. Three main reasons including stress level, constitutive model and the software ABAQUS itself are researched in this paper by numerical examples, and an extra analysis step is proposed for eliminating oscillation before loading the seismic wave.