A Hybrid Method Combining the Multitemporal Resolution Time-Domain Method of Moments With the Time-Domain Geometrical Theory of Diffraction for Thin-Wire Antenna Problems

2006 ◽  
Vol 54 (3) ◽  
pp. 953-960 ◽  
Author(s):  
A. Becker ◽  
V. Hansen
Keyword(s):  
Method Of Moments ◽  
Hybrid Method ◽  
Time Domain ◽  
Time Domain Method ◽  
Wire Antenna ◽  
Geometrical Theory ◽  
Thin Wire ◽  
Resolution Time ◽  
Geometrical Theory Of Diffraction ◽  
The Time Domain

scholarly journals A hybrid method combining the Time-Domain Method of Moments, the Time-Domain Uniform Theory of Diffraction and the FDTD

2007 ◽  
Vol 5 ◽  
pp. 107-113
Author(s):  
A. Becker ◽  
V. Hansen
Keyword(s):  
Method Of Moments ◽  
Hybrid Method ◽  
Time Domain ◽  
Time Domain Method ◽  
Thin Wire ◽  
Uniform Theory Of Diffraction ◽  
Domain Method ◽  
Inhomogeneous Bodies ◽  
Wire Antennas ◽  
The Time Domain

Abstract. In this paper a hybrid method combining the Time-Domain Method of Moments (TD-MoM), the Time-Domain Uniform Theory of Diffraction (TD-UTD) and the Finite-Difference Time-Domain Method (FDTD) is presented. When applying this new hybrid method, thin-wire antennas are modeled with the TD-MoM, inhomogeneous bodies are modelled with the FDTD and large perfectly conducting plates are modelled with the TD-UTD. All inhomogeneous bodies are enclosed in a so-called FDTD-volume and the thin-wire antennas can be embedded into this volume or can lie outside. The latter avoids the simulation of white space between antennas and inhomogeneous bodies. If the antennas are positioned into the FDTD-volume, their discretization does not need to agree with the grid of the FDTD. By using the TD-UTD large perfectly conducting plates can be considered efficiently in the solution-procedure. Thus this hybrid method allows time-domain simulations of problems including very different classes of objects, applying the respective most appropriate numerical techniques to every object.

scholarly journals A hybrid method combining the TD-MoM with the TD-UTD to calculate the transient radiation of thin dipoles in presence of a perfectly conducting screen

2005 ◽  
Vol 3 ◽  
pp. 431-436
Author(s):  
A. Becker ◽  
V. Hansen
Keyword(s):  
Frequency Domain ◽  
Method Of Moments ◽  
Hybrid Method ◽  
Time Domain ◽  
Free Space ◽  
Time Domain Method ◽  
Thin Wire ◽  
Uniform Theory Of Diffraction ◽  
The Time Domain ◽  
Conducting Screen

Abstract. A time domain Method of Moments algorithm (TD-MoM) is combined with the time domain version of the Uniform Theory of Diffraction (TD-UTD). By use of the TD-MoM the fields radiated from thin wire structures positioned in free space are determined. The TD-UTD is applied to calculate the fields scattered by a perfectly conducting screen. Both techniques are hybridized by adding possible reflected and diffracted fields in the TD-MoM algorithm and by using the TD-MoM solution to calculate the fields which impinge on to the screen. To show the accuracy of the developed hybrid method, numerical results are compared to results obtained by established frequency domain numerical codes.

Optimized Mooring Line Simulation Using a Hybrid Method Time Domain Scheme

2014 ◽  
Author(s):  
Niels Hørbye Christiansen ◽  
Per Erlend Torbergsen Voie ◽  
Jan Høgsberg ◽  
Nils Sødahl
Keyword(s):  
Hybrid Method ◽  
Time Domain ◽  
Computation Time ◽  
Mooring Line ◽  
Mooring Lines ◽  
Fem Model ◽  
Input Variables ◽  
The Time Domain ◽  
The Cost ◽  
Short Time

Dynamic analyses of slender marine structures are computationally expensive. Recently it has been shown how a hybrid method which combines FEM models and artificial neural networks (ANN) can be used to reduce the computation time spend on the time domain simulations associated with fatigue analysis of mooring lines by two orders of magnitude. The present study shows how an ANN trained to perform nonlinear dynamic response simulation can be optimized using a method known as optimal brain damage (OBD) and thereby be used to rank the importance of all analysis input. Both the training and the optimization of the ANN are based on one short time domain simulation sequence generated by a FEM model of the structure. This means that it is possible to evaluate the importance of input parameters based on this single simulation only. The method is tested on a numerical model of mooring lines on a floating off-shore installation. It is shown that it is possible to estimate the cost of ignoring one or more input variables in an analysis.

Sign in / Sign up

Export Citation Format

Share Document