in this paper, an analytical study of the forced vibrations of hexapod table is studied. considering external force as a time sinusoid force, forced vibrations of the platform are investigated. resonance frequencies and vibrations of the moving platform are also calculated in different directions. the results of the analytical approach are verified using fem simulation. modelling the harmonic m...

the vibrations produced by trains include two parts which are deterministic and random vibrations. due to variation of dynamic loads and patterns of load-time, the random vibration of moving train is one of the most important issues in the field of railway engineering. one of the important sources in producing the train vibrations is rail roughness and irregularities. in this paper, responses o...

Assassin bugs (Stenolemus bituberus) hunt web-building spiders by invading the web and plucking the silk to generate vibrations that lure the resident spider into striking range. To test whether vibrations generated by bugs aggressively mimic the vibrations generated by insect prey, we compared the responses of spiders to bugs with how they responded to prey, courting male spiders and leaves fa...

this paper deals with new method for designing the tuned mass dampers (tmd) with considering both transient and steady state responses, simultaneously. this formulation is presented for undamped vibrations. for this purpose, the absolute value of the structural displacement ratio is minimized numerically. this procedure leads to optimum value of tmd's specifications. for numerical verification,...

The purpose of this mini-review is to outline diversity of chest wall vibrations, specify biomechanical peculiarities and point out a few problems crucial for development of diagnostic and therapeutic applications of chest wall vibrations. The review considers two types of chest wall vibrations: spontaneous, induced by breathing, and forced (or artificial), induced by external vibration forces....

The purpose of this paper is to study the effect of presence of fluid within and around a poroelastic circular cylindrical shell of infinite extent on axially symmetric vibrations. The frequency equation each for a pervious and an impervious surface is obtained employing Biot’s theory. Radial vibrations and axially symmetric shear vibrations are uncoupled when the wavenumber is vanished. The pr...

the use of bio-ethanol as an alternative diesel engine fuel is rapidly increasing. bio-ethanol is mixed with diesel fuel at different ratios and used in ci and si engines. since vibrations have direct effects on users and engine components, for this reason analysis of vibration resulting from combustion in ci engines is very important. in this study, evaluation of vibration was performed for bo...

The use of distinguishable complex vibrations that have multiple spectral components can improve the transfer of information by vibrotactile interfaces. We investigated the qualitative characteristics of dual-frequency vibrations as the simplest complex vibrations compared to single-frequency vibrations. Two psychophysical experiments were conducted to elucidate the perceptual characteristics o...

Chatter vibrations are present in almost all cutting operations and they are the major obstacles in achieving desired surface finish. Chatter vibrations are the self excited vibrations, which has an adverse effect on surface roughness, dimensional accuracy of the machined components. This paper investigates the occurrence of regenerative chatter vibrations in centerless bar turning operation. T...