Wave displacement of rigid bodies and particles

The displacement of various particles and mechanical systems by waves finds wide use in technical devices, technological processes, takes place in non living and living nature. Here the system displaced by waves with four degrees of freedom is analyzed when one member of the system, while contacting with the working profile of the input member performing wave motion, provides motion to the output system.The obtained differential equations of motion of the system have been analyzed analytically and numerically. For the analytical investigation modification of the asymptotic method is used, which is based on the division of motion into the slow and quick motions. This method is justified when the frequencies of variation of slow motions are much smaller than the frequencies of quick motions.When the working surface of the input member moves according to the harmonic Rayleigh waves more detailed full investigations have been performed. The characteristics of transition to steady state and of stationary regimes of motions have been obtained, such as the conditions of existence and stability of the stationary regimes, curves of bifurcation, existing complicated motions

Dynamic study of transportation containers with packages

The paper studies the motion of transportation machine with packages on uneven road. Conditions of transportation that reduce the influence of harmful vibrations to the packages are determined. For this purpose the region was established where the slippage of packages with respect to the transported box of packages does not occur. The conditions for location of eigenfrequencies and forced frequencies are determined with the purpose to ensure that the system operates far from resonances. In order to avoid large overloads it is recommended to choose the velocity of motion in such a way, that the difference between the eigenfrequencies and the forced frequencies would be maxmin

Dynamic study of transportation containers with packages

The paper studies the motion of transportation machine with packages on uneven road. Conditions of transportation that reduce the influence of harmful vibrations to the packages are determined. For this purpose the region was established where the slippage of packages with respect to the transported box of packages does not occur. The conditions for location of eigenfrequencies and forced frequencies are determined with the purpose to ensure that the system operates far from resonances. In order to avoid large overloads it is recommended to choose the velocity of motion in such a way, that the difference between the eigenfrequencies and the forced frequencies would be maxmin

Vibroimpact mechanism in one separate case

It is known that in the vibroimpact system at the chosen values of parameters linear relationship between impact velocities and eigenfrequencies may exist. The purpose of this paper is to reveal the qualities of the systems of this type. Investigations are performed by analytical and numerical methods. It is determined that in the systems of this type nonlinear solutions with infinite series of harmonics exist. Multivalued stable and unstable regimes do not exist in the systems. The obtained analytical relationships enabled to reveal new qualities of the systems and to make useful conclusionsKauno technologijos universitetasSistemų analizės katedraVytauto Didžiojo universiteta

Vibrations of the nonlinear system in which stationary harmonic excited multivalued regimes in the vicinities of resonances do not exist

A nonlinear dynamical system is investigated which consists from a mass between two linear elastic connecting elements with different coefficients of stiffness. Laws of vibrations and characteristics of eigenvibrations of the system as well as of self-decaying vibrations of the system with damping and of the system with harmonic excitation are determined. Dynamical qualities of the system are revealed. It is shown that the system has infinite number of eigenfrequencies and that in the resonance zones multivalued stable and unstable motions do not exist in the systemKauno technologijos universitetasSistemų analizės katedraVytauto Didžiojo universiteta

Forced vibrations of vibro impact system with zero tightening with harmonic resonant excitation

An important problem for engineering practical applications is investigated: namely dynamics of the system by taking into account dissipative forces and with an aim that those steady state vibrations should be stable and single valued. This is achieved by choosing suitable parameters of the investigated system. Forced vibrations of vibro impact system with zero tightening with harmonic resonant excitation are investigated. Results for various typical parameters of the analysed system are presented. Dependence of characteristics of motion in steady state regime from the main parameters of the investigated system is investigated. The obtained results are useful in the process of design of vibro impact systems for use in technologies and machines of corresponding typeKauno technologijos universitetasSistemų analizės katedraVytauto Didžiojo universiteta

Patobulintos skaitmeninės holografinių interferogramų sudarymo procedūros

Procedures for plotting computer generated interferograms from the results of finite element can provide a realistic view of dynamic processes taking place in the analysed structures. Such visualisation is based on a solid physical background, doesn't require animation for representing dynamic processes, and is also important from the point of view of interpretation of experimental holograms. Enhanced numerical procedures are applied for obtaining the digital interferograms for three dimensional structural dynamicsKauno technologijos universitetasVytauto Didžiojo universiteta

Plotting isoclinics for hybrid photoelasticity and finite element analysis

Displacement-based finite element method formulations are coupled with stress-based photoelasticity analysis. As the stress field is discontinuous at the interelement boundaries, the introduced smoothing procedure enables the generation of high-quality digital images acceptable for hybrid experimental-numerical techniques. The proposed methods are applicable for the analysis of static and dynamic results of experimental photoelasticityKauno technologijos universitetasVytauto Didžiojo universiteta

On interpretation of fringe patterns produced by time average photoelasticity

The presented technique of interpretation of time average photoelastic images is not trivial. The photoelastic image is black when the object is in a state of equilibrium and the stresses are zeroes. The pattern of isochromatics changes dynamically when the object (and stresses) oscillate in time. Nevertheless, a pattern of fringes is formed in the process of time averaging, though the contrast of the picture is decreased. [...]Kauno technologijos universitetasVytauto Didžiojo universiteta

Wave displacement

Here the system displaced by waves with two degrees of freedom is analyzed when one member of the system, while contacting with the working profile of the input member performing wave motion, provides motion to the output system. For the analytical investigation modification of the asymptotic method is used, which is based on the division of motion into the slow and quick motions. This method is justified when the frequencies of variation of slow motions are much smaller than the frequencies of quick motions. More complicated cases are investigated by numerical methodsKauno technologijos universitetasVytauto Didžiojo universiteta