T H I S P A P E R is a review of the problem of noise and vibration with respect to manned space flight. For the purposes of this discussion, noise will be defined as the energy transmitted to a man through the air at all frequencies up to 15,000 cps. Vibration will be defined as all of the energy transmitted to a man through the structural components for all frequencies above 0.5 cps. The sepa...

This paper explores the vibration spectra for planetary gear systems by studying a kinematic model of vibration and comparing the model with measurements of two helicopter transmissions made in flight. The model and flight data include systems with both uniformly and nonuniformly spaced planet gears. This model predicts vibration to occur only at frequencies that are integer multiples of the pl...

The classical shell theory, first-order shear deformation theory, and third-order shear deformation theory are employed to study the natural frequencies of functionally graded cylindrical shells. The governing equations of motion describing the vibration behavior of functionally graded cylindrical shells are derived by Hamilton’s principle. Resulting equations are solved using the Navier-type s...

An analytical and numerical solution for the free vibration of laminated polymeric composite plates with different layups is studied in this paper. The governing equations of the laminated composite plates are derived from the classical laminated plate theory (CLPT) and the first-order shear deformation plate theory (FSDT). General layups are evaluated by the assumption of cross-ply and angle-p...

This paper describes vibration diagnosis based on electric faults. These faults could appear in electrical equipment in general, but this paper focuses on the case of transformer, induction and dc motor. In order to do the diagnosis there are analysed vibration signals from the piezoelectric accelerometer. This accelerometer is installed on the frame of the equipment. The signals acquired are a...

In this paper, two kinds of vibrations are considered for a composite Timoshenko rotor: longitudinal-torsional vibration and two plane transverse one. The kinetic and potential energies and virtual work due to the gyroscopic effects are calculated and the set of six governing equations and boundary conditions are derived using Hamilton principle. Differential quadrature method (DQM) is used as ...

many procedures suggest for reduction of responses of riser to vortex induced vibrations (viv). natural frequencies of marine risers is an important parameter that can affect the responses of riser to viv. change of riser properties such as top tension and bending stiffness can alter natural frequencies. in this study effects of riser specifications on the responses and fatigue damage of marine...

This paper compares performance of a piezoelectric vibration energy harvester, in terms of output power, under different types of vibration. The most common method used to characterize a vibration energy harvester is to excite the energy harvester under a sinusoidal vibration of its resonant frequency and measure the voltage across certain electrical loads. However, in practical applications, t...

in this study, the vibration of cracked plates is investigated using the differential quadrature method and experimental modal analysis. the crack, which is assumed to be open, is modeled by the extended rotational spring. with its finite length, the crack divides the plate into six segments. then, the differential quadrature is applied to the governing differential equations of motion and the ...

Semi-analytical solutions for vibration analysis of nonlocal piezoelectric Kirchhoff plates resting on viscoelastic foundation with arbitrary boundary conditions are derived by developing Galerkin strip distributed transfer function method. Based on the nonlocal elasticity theory for piezoelectric materials and Hamilton's principle, the governing equations of motion and boundary conditions are ...