one of the main dichotomies in syntactic analyses deals with the distinction between lexical and functional categories. functional categories gain in stature as the generative grammar moves ahead. they come into play in explaining the derivation stages of phrases and sentences. the present study critically evaluates different approaches to the role and function of one of these functional catego...

in the present paper, the aeroelastic stability of helicopter rotor blade is determined using aeroelastic frequency response function. the aeroelastic model of blade is obtained by combining dowell - hodges beam model with loewy unsteady aerodynamic theory which considers an unsteady wake beneath the rotor. equations are formed and aeroelastic frequency response functions are obtained by invert...

In this study, A finite element model based on the third order theory is presented for the active vibration control of composite beams with distributed piezoelectric sensors and actuators. For calculating the total charge on the sensor, the direct piezoelectric equation is used and the actuators provide a damping effect on the composite beam by coupling a negative velocity feedback control algo...

The use of equivalent beam models to estimate the dynamical characteristics complex tall buildings has been investigated by several authors. main reason is structural response estimation stochastic loads, such as wind and earthquake, using a reduced number degrees freedom, which reduces computational costs therefore gives designer an effective tool explore possible solutions. In this paper, nov...

This paper describes an analytical and experimental investigation of the property of modal disparity in a vibrating structure. For a given structure, the concept of modal disparity describes the structure’s ability to generate significant changes in the mode shapes by some type of on-the-fly structural modification. In the present study we consider a vibrating beam that experiences a controlled...

steel corrosion of bars in concrete structures is a complex process which leads to the reduction of the cross-section bars and decreasing the resistance of the concrete and steel materials. in this study, reliability analysis of a reinforced concrete beam with corrosion defects under the distributed load was investigated using the enhanced hasofer-lind and rackwitz-fiessler (ehl-rf) method base...

The nonlinear system becomes an area with numerous investigations over the past decades. The conventional modal analysis could not be  applied on nonlinear continuous system which makes it impossible to construct the reduced order models and obtain system response based on limited number of measurement points. Nonlinear normal modes provide a useful tool for extending modal analysis to nonlinea...

A method of complex orthogonal decomposition is summarized for the time-domain, and then formulated and justified for application in the frequency-domain. The method is then applied to the extraction of modes from simulation data of sampled multi-modal traveling waves for estimating wave parameters in one-dimensional continua. The decomposition is first performed on a transient nondispersive pu...

Modal control and spatial filtering technologies for vibration and/or structural acoustics radiation mitigation may be implemented through the use of distributed modal piezoelectric transducers with properly shaped electrodes which, in order to increase the robustness and stability of the controlled structural system, turn undesirable mode’s contributions unobservable and uncontrollable over th...

Vibration based techniques of structural damage detection using model updating method, are computationally expensive for large-scale structures. In this study, after locating precisely the eventual damage of a structure using modal strain energy based index (MSEBI), To efficiently reduce the computational cost of model updating during the optimization process of damage severity detection, the M...