according to high costs of phase shifters in antenna arrays, new methods for beam steering without phase shifter were introduced. frequency diverse array (fda) concept is another approach to beam steering problem. in this structure, the subsequent antenna elements are fed with stepped discrete frequencies causing continuous scanning of space in time. so a range-angle dependent scanning is made ...

Free vibration characteristics of continuous grading fiber orientation (CGFO) beams resting on variable Winkler and two-parameter elastic foundations have been studied. The beam is under different boundary conditions and assumed to have arbitrary variations of fiber orientation in the thickness direction. The governing differential equations for beam vibration are being solved using Generalized...

Abstract: It is assumed that a beam made of material has a physical nonlinear behavior. This beam is analyzed under the moving concentrated and distributed continuous loads. The vibration equations of motion are derived from the Hamilton's Principle and Euler–Lagrange Equation. In this study, the amplitude of vibration, circular frequency, bending moment, stress and deflection of the beam has b...

This paper studies dynamic stability of functionally graded beams with piezoelectric layers subjected to periodic axial compressive load that is simply supported at both ends lies on a continuous elastic foundation. The Young’s modulus of beam is assumed to be graded continuously across the beam thickness. Applying the Hamilton’s principle, the governing dynamic equation is established. The eff...

We use local quark-hadron duality to estimate the purely nonperturbative soft contribution to the γ * p → ∆ form factors. Our results are in agreement with existing experimental data. We predict that the ratio G * E (Q 2)/G * M (Q 2) is small for all accessible Q 2 , in contrast to the pQCD expectations that G * E (Q 2) → −G * M (Q 2).

Precast concrete structures in Iran are generally designed as continuous columns with hinged beams, thereby making them simple frames. In this system in site show walls in two directions of buildings guaranteed lateral resisting system. However, in order to obtain a seismic resisting frame, the connection between beam and column should be moment resisting and ductile, allowing the formation of ...