Today, modeling is critical for cognition and analysis of designers in industry field to meet their needs and design based on design requirements and available facilities to accelerate production and development of components of industrial engines. In this study, one structure has been proposed, designed, and analyzed based on turboshaft marine engine type to test this kind of engine in order t...

In this study, vibration of initially imperfect cracked thick plate has been investigated using the differential quadrature method. The crack modeled as an open crack using a no-mass linear spring. The governing equations of vibration of a cracked plate are derived using the Mindlin theory and considering the effect of initial imperfection in Von-Karman equations. Differential equations are dis...

in this paper, the rayleigh's quotient and the inverse vector iteration method are presented. the latter approach helps to obtain the natural frequencies and mode shapes of a structure. inverse vector iteration method with shifting enables to determine the higher modes. some basic theorems of linear algebra are presented and extended to study the free vibration of structures. the variation...

the natural frequencies and mode shapes of pneumatic tires are predicted using a geometrically accurate, three-dimensional finite element modeling. tire rubber materials and cord layers are represented independently using “shell element” available in cosmos. the effects of some physical parameters such as the inflation pressure tread pattern, thickness of belts and ply angles to the natural fre...

One analytical technique for assessing the health of a structure such as a building or bridge is to estimate its mode shapes and frequencies via vibrational data collected from the structure. A change in a structure’s modal parameters could be indicative of damage. Due to the considerable time and expense required to perform manual inspections of physical structures, and the difficulty of repea...

Structural damage detection is a field that has attracted a great interest in the scientific community in recent years. Most of these studies use dynamic analysis data of the beams as a diagnostic tool for damage. In this paper, a massless rotational spring was used to represent the cracked sections of beams and the natural frequencies and mode shape were obtained. For calculation of rotational...

The vibration characteristics of piezoelectric hollow-disc transducers were investigated in this paper. It was assumed that the vibration modes were coupled in the axial and radial directions. Theoretically the differential equations of piezoelectric motions were derived in terms of the axial and radial displacements and the electric potential. Solutions of the boundary value problem yielded th...

In this paper, we present a multimedia system designed to facilitate learning of alphabetical handwriting of various languages by incorporating visual, auditory, and haptic feedback. An XML-based schema has been used to easily introduce new characters from other languages. The system supports two modes of operation: a learning mode and an evaluation mode. In the learning mode, a user can see, h...

This paper contains a linear analysis of pulse shapes produced by a spatial and temporal delta-function disturbance of cyclotron-resonance-maser modes for the case where the initial equilibrium state is free of radiation. A pinch-point analysis based on the theory of Briggs and Bers is employed. Numerical and analytical techniques are developed for the straightforward calculation of pinch-point...

In this paper, a fractal photonic crystal fiber (F-PCF) based on the 1st iteration of Koch fractal configuration for optical communication systems is presented. Complex structure of fractal shape is build up through replication of a base shape. Nowadays, fractal shapes are used widely in antenna topics and its usage in PCF has not been investigated yet. The purpose of this research is to compar...