جستجوی مقالات مرتبط با کلیدواژه "beam" در نشریات گروه "برق"

One of useful methods for strengthening for reinforced concrete frames, is to use steel prop and crub in connections, alone or combined with beam's revival steel sheets and column jacketing with steel sheets or profiles. In this paper, after modeling and verifying application of model, behavior of RC frames, strengthened with this method was studied. For this purpose, a RC frame has been strengthened in 4 general ways (crub and prop, crub and prop with revival sheet among two beam’s crub, crub with column jacketing in the bottom of column’s crub region, combination of three mentioned moods) with three different prop’s sectional area. Results showed that using crub and prop increases stiffness and strength of frame, significantly. If crub and prop are used with column jacketing for strengthening RC frames, frames’ strength increase up to 3.3 times of ordinary frame. Adding beam revival sheet to crub and prop, causes sooner yielding and bulking in compressive prop.

In recent years, damage detection and structural health monitoring methods for civil and mechanical structures, have been developed in different fields. Structural health monitoring is the implementation of a damage identification strategy to the civil engineering infrastructures. Damage is defined as changes to the material and/or geometric properties of these systems, including changes to the boundary conditions and system connectivity. Damage affects the current or future performance of such systems. Structural health monitoring and damage detection has several techniques, the methods are categorized based on the type of measured data used, and/or the technique used to identify the damage from the measured data. Wavelet transform is relatively new mathematical tool for signal processing. Wavelet transform gives more information on non-stationary signal that the Fourier transform was unable to provide them. One of the most important issue of application of the mathematical transforms such as wavelet, is structural health monitoring and structural damage detection. Especially the identification of damage in structures at the beginning is important. In this paper a simple method based on Wavelet transform has been utilized in order to localize and quantify the crack in simple supported beam; in which, the deflection of the beam subject to static loading would be decomposed by discrete wavelet transforms. In decomposition diagrams has been assessed for various scenarios of damage. Finally the performance of the applied method has been evaluated for different state of cracking.

Sensitivity analysis has been done in two-dimensional phased array antennas. Numerical methods of computing the beam pointing angle in these arrays has been investigated. The used numerical method has been validated by numerical computing the array factor and beam pointing angle if the array. Deviation of beam pointing angle due to phase deviation of each element of the array is computed and it is shown that the phase error of peripheral elements have more influence in beam pointing angle in two-dimensional arrays than the phase error of inner elements. This result is important because by knowing it we should phase the peripheral elements more accurately in comparison of phasing the inner elements. For example in choosing the phase shifters، we can use the more accurate and expensive ones for the peripheral elements and the phase shifters with lower accuracy and less expensive can be used for the inner elements which has less impact on beam pointing error.