In this paper a method is presented to identify the parameters of a structure exhibiting weak nonlinear behavior using vibration test data. The identification approach is based on an extension of a linear frequency domain method for the direct identification of incomplete system matrices to the nonlinear case. The basic identification equations are extended by additional stiffness and damping t...

   The main purpose of the present investigation is to analyze more comprehensively the size-dependent nonlinear free vibration response of multilayer functionally graded graphene platelet-reinforced composite (GPLRC) nanobeams. As a consequence, both of the hardening stiffness and softening stiffness of size effect are taken into consideration by implementation of the nonlocal str...

It is predicted that energy consumption will increase by 56% between year 2010 and 2040. To cope with this upcoming energy demand, innovative technologies have been developed in recent decades to harvest energy from the environment such as wind, solar, tide and vibration. Harvesting energy from structural vibration presents two major challenges: efficiency and vibration control. In particular, ...

A tremendous amount of research has been performed on the design and analysis of vibration energy harvester architectures with the goal of optimizing power output; most studies assume idealized input vibrations without paying much attention to whether such idealizations are broadly representative of real sources. These “idealized input signals” are typically derived from the expected nature of ...

in this paper, we implemented the modified iteration perturbation method (mipm) for approximating the periodic behavior of a tapered beam. this problem is formulated as a nonlinear ordinary differential equation with linear and nonlinear terms. the solution is quickly convergent and does not need to complicated calculations. comparing the results of the mipm with the exact solution shows that t...

A mathematical model of a cracked rotor and an asymmetric rotor with two disks representing a turbine and a generator is uti­ lized to study the vibrations due to imbalance and side load. Nonlinearities typically related with a “breathing” crack are included using a Mayes steering function. Numerical simulations demonstrate how the variations of rotor parameters affect the vibration response an...

Abstract In this paper, a nonlinear vibration differential equation is established for the moment when tennis racket hits ball. At same time, we deduce relationship between string tension and separation time distance of hitting speed. Then article analyzes damping We use ANSYS finite element analysis software solid modeling modal rackets. The natural frequency was obtained through verification ...

Vibration behavior of different types of porous functionally graded (FG) conical sandwich shells are investigated based on a modified high order sandwich shells theory for the first time. Sandwich shell includes FG face sheets covering a homogeneous core and the second one includes homogeneous face sheets and a FG core. Power law rule modified by considering two types of porosity distributions ...

In this paper, vibrations and bifurcation of a damped system consists of a mass grounded by linear and nonlinear springs and a nonlinear damper is studied. Nonlinear equation of motion is derived using Newton’s equations. Approximate analytical solutions are obtained using multiple time scales (MTS) method. For free vibration, the approximate analytical results are compared with the numerical i...

Noise reduction has been accomplished in atomic force microscopy by applying a high frequency, low amplitude vibration to the cantilever while it is in contact with a surface. The applied excitation ~.200 kHz; ;1 nm! is acoustically coupled to the tip and dampens the resonance Q factors of the system. The applied frequency is well above the bandwidth of the acquisition system ~50 kHz!. We call ...