The influence of the impact model on the dynamic behavior of a vibro-impact system with non-ideal excitation is analyzed in this paper. The system consists of a crank-slider mechanism and an oscillator, and its mathematical model is derived using Lagrange’s equations of motion. Three soft impact models (Spring-Damper, Hertz, and Brake) and one hard impact model (Newton) are considered. The system response is analyzed numerically using frequency response diagrams, phase portraits, displacement-time histories, and basins of attraction. Three response regions are identified for all four models: non-impact, impact, and multiple solution regions. The multiple solution region corresponds to excitation-parameter values for which the system response depends on the initial conditions. For all models, the non-impact regime occurs for , while the impact regime occurs for . The largest differences between the models occur in the multiple solution region. Its upper boundary is  for the Newton model,  for the Spring-Damper model, and  for the Hertz and Brake models. At lower values of the excitation control parameter, all four models predict similar dynamic responses, whereas noticeable differences emerge at higher values. These results demonstrate that impact-model selection becomes increasingly important at higher excitation levels for accurately predicting the system response and its sensitivity to initial conditions.

This paper analyzes the application of a vibro-impact element as a dynamic absorber for a Duffing oscillator. The Duffing oscillator is a nonlinear oscillator, modeled here as a single-degree-of-freedom system with a nonlinear spring. The complete system consists of a body performing translational oscillatory motion, a drive mechanism, a slider, a spring that connects the oscillator to the slider, and a vibro-impact element, in the form of the ball, that performs translational motion with impacts. For comparison, the response of the Duffing oscillator without the absorber is also analyzed. The differential equations of motion of both systems are derived using Lagrange’s equations of the second kind, and solved numerically. The results are presented in the form of amplitude–frequency diagrams and time–displacement diagrams. It is shown that the amplitude of the main body is reduced when it is coupled with an impact element. The way in which this is affected by the stiffness of the spring, that connects the ball and Duffing oscillator, is presented. For selected excitation frequencies the basins of attraction of the ball are obtained. In this way, the set of possible initial conditions for which the system behaves like vibro-impact or purely oscillatory one, is determined.

In this paper, the dynamic analysis of a vibro-impact system with ideal excitation and various friction models is performed. A physical model of an oscillating mechanical system with possible impact occurrence is presented and the corresponding mathematical model is derived by using Lagrange’s equations of motion. To describe interaction between impact element and environment, three different friction models are considered: Coulomb, viscous and Coulomb-Stribeck model. Newton’s impact law with a coefficient of restitution is employed to describe relationship between pre-impact and post-impact velocities. The dynamic behavior of the vibro-impact system under the ideal excitation, where the system does not influence the excitation source, is investigated for each friction model by numerically solving the governing equations. The results of numerical analysis are presented through amplitude-frequency diagrams, displacement-time responses and phase portraits. The main objective is to determine the influence of different friction models on amplitude-frequency diagrams, particularly on the regions exhibiting impact and non-impact behavior. For parameter regions with multiple coexisting solutions, basins of attraction are constructed to illustrate the dependence of the system regime on initial conditions.

Abstract This paper presents the study of deformations and Von-Misses stresses of the main shaft system during opening and closing operations of a rotary SF6 load break switch (LBS). The shaft consists of three axially connected parts made of steel where components are on ground potential and of plastic material, which is on high potential. The insulating shaft carries three rotating knife-blade contacts for the three phases. Static deformation of the insulating shaft is calculated by applying a defined torque between the two ends of the shaft. The results allow deducing the dynamic deformation. Maximum values of Von-Misses stresses are located at the geared connection between the plastic and the steel shaft. The rotation of the shaft system is measured synchronously by two optical rotary encoders in the front and rear sides of the LBS. The results confirm the twisting of the shaft system and provide its elastic deformation values. Travel curves obtained on both side of the LBS show different courses with respect to overtravel and rebound. Discrepancies can be explained by the deformation of the main shaft due to the acting forces, whereas manufacturing tolerances resulting in loose have a certain contribution.