Search results for "boundary"
showing 10 items of 1626 documents
Highly efficient full-wave electromagnetic analysis of 3-D arbitrarily shaped waveguide microwave devices using an integral equation technique
2015
A novel technique for the full-wave analysis of 3-D complex waveguide devices is presented. This new formulation, based on the Boundary Integral-Resonant Mode Expansion (BI-RME) method, allows the rigorous full-wave electromagnetic characterization of 3-D arbitrarily shaped metallic structures making use of extremely low CPU resources (both time and memory). The unknown electric current density on the surface of the metallic elements is represented by means of Rao-Wilton-Glisson basis functions, and an algebraic procedure based on a singular value decomposition is applied to transform such functions into the classical solenoidal and nonsolenoidal basis functions needed by the original BI-RM…
Optimization of the domain in elliptic variational inequalities
1988
This paper is concerned with a nonsmooth shape optimization problem for the Signorini unilateral boundary-value problem. The necessary optimality conditions are derived. The results of computations are presented.
Boundary accessibility and elliptic harmonic measures
1988
Suppose G is a bounded domain in R n such that the complement of G satisfies a capacity dcnsity condition. It is shown that all elliptic measures in G have a support set with Moreover, the capacity density condition cannot be removed. A nonlinear version of the result is also given.
DESIGN BY MATERIAL: FROM MATERIAL TO FORM THROUGH CAD MODELLING
2021
AbstractFor Aristotelian scholars, matter is identified as the subject of change, while form is the boundary of matter. Design is a process of bringing about change. From a design perspective, material is what an entity is made from; form is what makes a thing what it is. Based on the principle, “form is the boundary of matter”, this paper proposes a Design by Material method, thereby addressing the knowledge gap of a systematic method for designing according to material. This method is predicated on the material specification as the first input in the design process. A formal model is built in which the material acts as a trigger and driver for the design process. The method is implemented…
S-domain modeling of conducting post in rectangular waveguides by the BI-RME method
2002
This paper describes the application of the Boundary Integral - Resonant Mode Expansion method to the modeling of a conducting post in a rectangular waveguide. The mathematical model of this structure is determined in a very short time, in the form of pole expansion of the Generalized Admittance Matrix in the s-domain. This model is very useful in the CAD of combline or interdigital filters.
Structural Health Monitoring Procedure for Composite Structures through the use of Artificial Neural Networks
2015
In this paper different architectures of Artificial Neural Networks (ANNs) for structural damage detection are studied. The main objective is to investigate an ANN able to detect and localize damage without any prior knowledge on its characteristics so as to serve as a real-time data processor for Structural Health Monitoring (SHM) systems. Two different architectures are studied: the standard feed-forward Multi Layer Perceptron (MLP) and the Radial Basis Function (RBF) ANNs. The training data are given, in terms of a Damage Index ℑD, properly defined using a piezoelectric sensor signal output to obtain suitable information on the damage position and dimensions. The electromechanical respon…
Experimental characterisation of the CIRA plasma wind tunnel SCIROCCO test section
2008
Abstract During the Validation Phase of the CIRA-PWT SCIROCCO Facility located at Capua (Italy), a test campaign has been carried out to verify the performances of the facility with the use of the two conical nozzle configurations “D” and “F” with exit diameters are, respectively of, 1150 and 1950 mm. For the first time the data results of the tests have been used to characterize the plasma flow in the test section of the facility. In particular, analytical relationships between the main thermo-fluid-dynamic parameters in the test section and the reservoir conditions of the facility have been found, and compared to the CFD prediction developed during the Design Phase of the facility. Very i…
Numerical Analysis of Piezoelectric Active Repair in the Presence of Frictional Contact Conditions
2013
The increasing development of smart materials, such as piezoelectric and shape memory alloys, has opened new opportunities for improving repair techniques. Particularly, active repairs, based on the converse piezoelectric effect, can increase the life of a structure by reducing the crack opening. A deep characterization of the electromechanical behavior of delaminated composite structures, actively repaired by piezoelectric patches, can be achieved by considering the adhesive layer between the host structure and the repair and by taking into account the frictional contact between the crack surfaces. In this paper, Boundary Element (BE) analyses performed on delaminated composite structures …
Numerical Modelling of Room Thermal Comfort Conditions
2006
Particular heat transfer coefficients of building elements gives quantitative notion only about heat losses through this building element. Analysis of the overall heat balance and heat losses of complete building and study of particular contribution of building elements in overall balance allows one to figure out the state of the building and find the building elements of bounding construction with most significant heat losses. Project variants of the buildings (or rebuilding in case of renovation), which ensure the desirable economy of energy and proportions of investments can be find varying the proportions of the surface area of building elements (e.g., windows and doors). A lot of facto…
Filling defects in a ceramics forming process
1997
Publisher Summary This paper presents a simple semi-heuristic method to predict mold filling defects in a porcelain forming process. It involves both a mechanical modelling of this process as a squeezing flow, and a postprocessing calculus that unable a defects prediction as soon as the shape and the size of artistic reliefs are known. This shape analysis is carried out with a multi resolution wavelet analysis. The chapter models the filling stage and to propose a criterium to avoid any filling defect that could waste the quality of the drawings. It illustrates a simplified modelling of the process during which the “turning” stage is approximated by the deformation under pressure of a Norto…