جستجوی مقالات مرتبط با کلیدواژه « Different boundary conditions » در نشریات گروه « مکانیک »

Nowadays, rotating cylindrical shells have industrial applications such as centrifuges, turbines, dryers, rotating shafts, motors and rotors. Therefore, it seems necessary to study their vibrations. This research analyzes and investigates the effect of elastic mechanical properties on shell-like and beam-like behavior in the vibrations of cylindrical shells made of materials with gradient properties (FGM) with different boundary conditions, considering the effect of the length scale parameter with values different and also the effect of varying radius and thickness has been discussed. The results show that the modulus of elasticity and Poisson's ratio with different values ​​have no effect on the vibration behavior of cylindrical shells made of materials with gradient properties, and also with the increase of the constraint (boundary conditions), the displacement (displacement) is less and the natural frequency increases. and the effect of the boundary conditions decreases with the increase of the length parameter. Finally, a relationship has been obtained to show the behavior change from shell-like to arrow-like. The results are in good agreement with other literature.

In present study, size- dependent static displacement analysis of nanotube under electrostatic force with considering the surface effects and different boundary conditions is investigated. The results of this analysis are obtained for four different boundary conditions, namely pinned-pinned, fixed- fixed, fixed- pinned and fixed- free. Also, the nanotube is subjected to magnetic field, electrostatic actuation, mechanical and thermal force. In the investigation, the governing equation of motion are achieved using the Eringen's theory and this equation is calculated by using the weighted residual method. Also, velocity of fluid, length scale parameter, magnetic field, electrostatically voltage, effect of surface layer and different boundary conditions on the static displacements has been studied. Finally, the validity of the results by comparing them with the results of the numerical methods in previous research is investigated, in which there is very good agreement between the results of the present work and previous studies. It is obvious that the structural stiffness is increased with increases in the effect of surface layer and the static displacements increase with the increases of the velocity of fluid. In addition, it is shown that the stiffness of nanotube and the dimensionless static displacements, respectively, is decreased and increased with increases in the length scale parameter.

This paper deals with the effect of Poisson's ratio on the static response of smart laminated composite beams. The actuation performance of smart beams with extension and shear mode piezoelectric orientation has been investigated. The first order and high order shear deformation beam theory has been implemented for modelling the problem. The piezoelectric stress resultants are expressed in terms of Heaviside discontinuity functions. The state space approach is used to obtain an analytical solution for the response of smart beams with different boundary conditions. The effect of actuator length, location of piezoelectric patches, order of theory, fibre orientation, boundary condition and Poisson's ratio on the beam deflection, has been investigated. Also the response of beam with complete piezoelectric layer has been obtained with the same procedure and compared with the solution for the beams with piezoelectric patch of same length. Results show that neglecting Poisson's effect in calculations causes significant errors in the response of angle ply beam with extension mode actuators.