Homogeneous Elliptic Cylinder Research Articles

Eccentric impact of an ice feature: linearized model

Eccentric impacts of an ice feature against a floating or stationary offshore structure or ship are much more likely than a head-on collision. Both numerical models and analytical evaluations have demonstrated that eccentricity of impact leads to a significant decrease in the maximum ice load as compared to a head-on collision. This fact should have a great influence on the definition of the design ice load for structures subjected to impacts with moderately sized floating ice features. The present paper deals with a relatively simple model of ice-structure interaction which describes an ice feature motion in a horizontal plane (three-degrees-of-freedom model). The instant reaction force (i.e. ice failure load) is assumed to be directly proportional to indentation depth. In spite of simplicity of the model, analytical expressions for reduction in ice force due to eccentricity obtained seem to be valid for more general situations. It is shown that the relative reduction in the maximum reaction force due to impact eccentricity does not depend on the effective stiffness of contact. The influence of the frictional force on the maximum ice load has been considered as well. As it follows from the analysis of linearized model of interaction, the reduction coefficient does not change dramatically if frictional effects are taken into account. The general conclusions and results are readily illustrated by the example of interaction between homogeneous elliptical cylinder and rigid wall.

Electromagnetic wave scattering by a two layered piecewise homogeneous confocal elliptic cylinder

The scattering properties of a homogeneous elliptic cylinder with a confocal dielectric or magnetic coating are investigated analytically. The method of separation of variables is used to determine, exactly, the field distributions in each region for both transverse electric and transverse magnetic excitations. The technique can be easily extended to handle any number of layers. The behavior of the scattered field in the far zone is illustrated with numerical results for different core and coating material types, axial ratios, and electrical sizes.

The parameters of an infinite homogeneous elliptical cylinder determined from its gravity effects

The Fourier transform of the vertical component of the attraction of a homogeneous horizontal infinite elliptical cylinder is computed. By comparing this function with the Fourier transform of the vertical component, determined experimentally, it is possible to determine the mass of the cylinder per unit length, as well as the position of the centre and of both the foci of the ellipse representing the cross-section of the cylinder.

Die Schwerewirkungen eines elliptischen Zylindersegmentes

A method has been derived for computing the gravity effect of a segment of an infinite homogeneous elliptical cylinder. The initial data was represented by formulae expressing the components of the field of gravity of a homogeneous two-dimensional body by means of line integrals. The method is based on the integration of theln R function over the boundary of the cross-section of the attracting body, R being the distance from a fixed point in which the gravity effect is determined. The problem was solved in confocal co-ordinates.