ANALYSIS AND SYNTHESIS OF RADIATION PATTERNS FROM CIRCULAR APERTURES

1960 ◽  
Vol 38 (1) ◽  
pp. 78-99 ◽  
Author(s):  
A. Ishimaru ◽  
G. Held
Keyword(s):  
Radiation Pattern ◽  
Traveling Wave ◽  
Design Method ◽  
Source Distribution ◽  
Circular Aperture ◽  
Narrow Beam ◽  
Wave Type ◽  
Numerical Examples ◽  
Analysis And Synthesis ◽  
Improved Design

Part I considers the problem of determining the source distribution over a circular aperture required to produce a prescribed radiation pattern. In particular, the problem of optimizing the narrow broadside pattern from a circular aperture is discussed in detail and an improved design method over Taylor's for line source is devised. Numerical examples are given.Part II deals with the analysis of the radiation pattern from a circular aperture from γ1 to γ2 with the traveling wave type source functions. Expressions suitable to the analysis and the synthesis are obtained and the narrow-beam and shaped-beam synthesis are discussed.

Improved design method for 2-arch tunnel

2007 ◽  
Author(s):  
Seok-Won Lee ◽  
Wan Gi Jeon ◽  
Kyeong-Han Jeong ◽  
Hyun-Ho Ahn ◽  
Ju Hyoung Lee
Keyword(s):  
Design Method ◽  
Improved Design

Improved design method for continuous-time quadrature bandpass ADCs

2005 ◽  
Vol 41 (8) ◽  
pp. 461 ◽  
Author(s):  
S. Reekmans ◽  
J. De Maeyer ◽  
P. Rombouts ◽  
L. Weyten
Keyword(s):  
Continuous Time ◽  
Design Method ◽  
Improved Design

scholarly journals Improved design of roller linear guide for heavy load based on finite element method and measurement

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401880015
Author(s):  
Xianchun Song ◽  
Hongjian Chen ◽  
Hongkui Jiang ◽  
Xiangrong Xu ◽  
Yanfeng Li ◽  
...  
Keyword(s):  
Finite Element ◽  
Sliding Friction ◽  
Design Method ◽  
Friction Torque ◽  
Experimental Investigations ◽  
Heavy Load ◽  
Linear Guide ◽  
Roller Guide ◽  
Element Simulation ◽  
Improved Design

Roller linear guides are key components in machine tool. The accuracy and efficiency of a machine toll are determined by the stiffness and friction torque of roller guide. This study proposes an improved design method for roller guide. The influences of the rollers profile on stiffness, stress distribution of roller linear guide are analyzed using finite element simulation. In this work, the design of the roller, slider, and the overall structure is modified. Moreover, experimental investigations on noise and sliding friction of roller linear guide are compared to validate the proposed design method. It seems that the proposed design can improve the dynamical performance of the roller linear guide.

On the Design of a Long-Stroke Beam-Based Compliant Mechanism Providing Quasi-Constant Force

2019 ◽  
Author(s):  
Pietro Bilancia ◽  
Alessandro Geraci ◽  
Giovanni Berselli
Keyword(s):  
Compliant Mechanism ◽  
Design Method ◽  
Reaction Force ◽  
Constant Force ◽  
Physical Prototype ◽  
Flexible Behavior ◽  
Improved Design ◽  
The One ◽  
Long Stroke ◽  
Integrated Software

Abstract In this paper the design of a linear long-stroke quasi-constant force compliant mechanism (CM) is presented and discussed. Starting from a flexure-based slider-crank mechanism, providing the required constant force within a rather limited deflection range, the paper reports about the shape optimization carried out with the specific aim of extending the available CM operative range. The proposed device is suitable in several precision manipulation systems, which require to maintain a constant-force at their contact interface with the manipulated object. Force regulation is generally achieved by means of complex control algorithms and related sensory apparatus, resulting in a flexible behavior but also in high costs. A valid alternative may be the use of a purposely designed CM, namely a purely mechanical system whose shape and dimensions are optimized so as to provide a force-deflection behavior characterized by zero stiffness. In the first design step, the Pseudo-Rigid Body (PRB) method is exploited to synthesize the sub-optimal compliant configuration, i.e. the one characterized by lumped compliance. Secondly, an improved design alternative is evaluated resorting to an integrated software framework, comprising Matlab and ANSYS APDL, and capable of performing non-linear structural optimizations. The new embodiment makes use of a variable thickness beam, whose shape and dimensions have been optimized so as to provide a constant reaction force in an extended range. Finally, a physical prototype of the beam-based configuration is produced and tested, experimentally validating the proposed design method.

Improved Prediction of External Pressure Collapse of Seamless Pipe

2009 ◽  
Author(s):  
Josef Navarro ◽  
Philip Cooper
Keyword(s):  
Cross Section ◽  
Wall Thickness ◽  
Design Method ◽  
External Pressure ◽  
Thickness Variation ◽  
Seamless Pipe ◽  
Line Pipe ◽  
Collapse Pressure ◽  
Average Wall Thickness ◽  
Improved Design

Seamless pipe typically features well controlled average wall thickness around its cross-section, but is prone to significant local thickness variation arising from the manufacturing process. Pipeline design codes, such as DNV OS-F101, provide little guidance on how to treat thickness variation whilst designing for collapse resistance. Standard practice is to consider minimum wall thickness across the whole cross-section, an assumption that two dimensional finite element simulations have proven conservative. This justifies the need for an improved design method. A program of simulations has been carried out to investigate the effect of wall thickness variation on collapse pressure. A modification to the DNV OS-F101 collapse design equation using average wall thickness over the whole crossection together with a fabrication factor is presented based on the results of this study. The fabrication factor de-rates the collapse pressure according to the amount of thickness variation present. The correction has been calibrated for thickness variations up to the maximum permitted by typical line pipe specifications. A number of FE trials demonstrate that the proposed formula predicts simulated collapse pressures with 98% accuracy. Adopting this method could provide significant wall thickness savings for deep water flowlines which in turn could lead to a reduction in steel costs and transportation and lay vessel requirements.

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