For reflector antennas and mirrors with diameters < 50 ? Physical Optics (PO) and the Physical Theory of Diffraction (PTD) are very fast and accurate calculation methods for determining the scattered fields. In optics where the diameter of the mirrors >> 1000 ? ray tracing methods are sufficient means of determining the scattered fields. However, in the Quasi-optical range in between these wave...

The structural analysis of an infinite unsymmetric laminated composite Timoshenko beam over Pasternak viscoelastic foundation under moving load is studied. The beam is subjected to a travelling concentrated load. Closed form steady state solutions, based on the first-order shear deformation theory (FSDT) are developed. In this analysis, the effect of bend-twist coupling is also evaluated. Selec...

Crack identification is a very important issue in mechanical systems, because it is a damage that if develops may cause catastrophic failure. In the first part of this research, modal analysis of a multi-cracked variable cross-section beam is done using finite element method. Then, the obtained results are validated usingthe results of experimental modal analysis tests. In the next part, a nove...

this paper describes experimental and numerical investigations on two specimens of frames composed of steel reinforced concrete beam and angle-steel concrete column under horizontal low cyclic loading. based on the test results, the relationship curves of the horizontal load-displacement and the failure modes are acquired. meanwhile the hysteretic behaviors, skeleton curves, stiffness degradati...

Analysis of a laminated composite beam under impact by a rigid particle is investigated. The importance of this project is to simulate the impact of objects on small scale aerial structures. The stresses are considered uni- axial bending with no torsion loading. The first order shear deformation theory is used to simulate the beam. After obtaining kinematic and potential energy for a laminated ...

This paper sheds more light on the co-rotational element formulation for beams with uniform cross-section. The co-rotational elements are commonly used in problems in which a structure undergoes a large deformation. In this study, the foregoing element obeys the Euler-Bernoulli beam assumptions. Unlike the formulations presented in the literature, in this paper, a number of local nodal coordina...

Cracks cause to change dynamic response of beams and make discontinuity in slope of the deflection of the beams. The dynamic analysis of the Euler-Bernoulli cracked beam on the elastic foundation subjected to the concentrated load is presented in this paper. The stiffness of the elastic foundation and elastic supports influence on vibrational characteristics of the cracked beam. The Dynamic Gre...

Abstract: In this research, at first, the natural frequencies of a cracked beam are obtained analytically, then, location and depth of a crack in beam is identified by neural network method. The research is applied on a beam with an open crack for three different boundary conditions. For this purpose, at first, the natural frequencies of the cracked beam are obtained analytically, to get the ex...