Deflection (engineering)

About: Deflection (engineering) is a research topic. Over the lifetime, 30862 publications have been published within this topic receiving 298849 citations.

A beam steering technique using dielectric wedges

Abstract: The thesis describes a method of' beam steering aimed at producing a useful amount of deflection of an antenna beam from boresight, by a simple and Inexpensive method. For large antennas, It is difficult, as well as expensive, to steer the beam by more than a few beamwidths. The method studied was developed with particular reference to the beam steering requirements of Direct Broadcast Satellite flat plate antennas. The method involves two dielectric wedges, having circular faces, placed In front of the antenna. By adjusting the relative angular position of the wedges, the beam can be steered In any direction, up to a maximum value from the antenna boresight direction. The maximum value of the deflection is determined by the wedge angle and the dielectric constant of the wedge material. This method of beam steering Is Independent of frequency. Frequency limitations are, however, set by the need for a matching layer on the wedge faces to reduce the loss due to reflection and also due to interference of multiple reflection effects on the radiation pattern. Extensive investigations are made (both theoretical and experimental) to predict the performance of the wedges as the beam Is steered. The effect of reflection is studied and a new matching technique is devised. Other practical considerations for example, stepping the wedges for weight reduction, the effect of loss in the dielectric material and cross polar performance are also taken into account. Some effort is given to explore the possibility of using metal loaded artificial dielectrics using polyurethane as the base material. Finally, a number of charts are presented to determine the amount of beam steering for an arbitrary position of the wedges.

An integral approach for large deflection cantilever beams

Abstract: A new integral approach is proposed to solve the large deflection cantilever beam problems. By using the moment integral treatment, this approach can be applied to problems of complex load and varying beam properties. This versatile approach generally requires only simple numerical techniques thus is easy for application. Treatment for typical loading and beam property conditions are presented to demonstrate the capability of this approach.

Fe and simplified models of steel plate shear wall

Abstract: A nonlinear finite-element model for steel plate shear walls was developed and then tested using the as-built dimensions and measured material properties of a large-scale four-story test specimen. When a nonplanar initial plate geometry and measured residual stresses were included in the model, it gave an excellent prediction of the load versus deflection response. Furthermore, a good prediction of the ultimate strength of the shear wall was obtained even when the second-order effects were neglected. Another analytical method is presented that is useful for the prediction of monotonic behavior. In this relatively simple plane frame model, the infill plate is represented as a series of tension strips. The model gave a good prediction of the behavior of the four-story shear wall specimen. An associated hysteresis model also gave good predictions of observed cyclic behavior. The models account for inelastic behavior in both the infill panels and the frame members.

Wide-angle, low-voltage electro-optic beam deflection based on space-charge-controlled mode of electrical conduction in KTa1−xNbxO3

Abstract: An electro-optic beam deflector with unprecedented performance is demonstrated. A full deflection angle of 250mrad (=14.3°) has been achieved by applying only ±250V to a 0.5-mm-thick KTa1−xNbxO3 crystal with a short interaction length of 5.0mm. The operating principle is investigated and the origin of the deflection phenomenon is attributed to a nonuniform electric field induced by space-charge-controlled electrical conduction in the crystal.

Method for checking beam steering in an ion beam therapy system

Abstract: The invention relates to a method for checking beam steering in an ion beam therapy system comprising a raster scanning device which is mounted in a beam steering system (6, 8) and presents vertical deflection means (13) and horizontal deflection means (14) for the vertical and horizontal deflection of a treatment beam (11) perpendicular to the direction of said beam so that the treatment beam (11) is deflected by the raster scanning device on to an isocentre (10) of the irradiation site and scans a defined area surrounding said isocentre (10). The method makes use of redundant means for the redundant termination of beam extraction and verifies both whether said means function correctly and whether beam steering dipoles situated in the beam steering system can be switched on and off.