Dome-Type Space Structures of Ellipsoidal Form

Abstract

A dome structure is usually spherical. This means, that it has the same radii in all directions. This shape can be altered by compressing or stretching it in any of the three main axes of the co-ordinate system. In that case a tri-axial ellipsoid is obtained. A horizontal cross-section in the XY-plane (see Fig. 1) then has the form of an ellipse. Any vertical cross-section through the Z-axis is an ellipse also, having its foot points in opposite positions on the horizontal ellipse. The equation of an ellipse is usually of the second power, but to this equation can be given a more general character if this power can be chosen freely – possibly individually in both directions. This offers a method to alter the shape of the sphere substantially. Another way to influence the appearance - and hence the structural characteristics – of a spherical structure is by varying its subdivision pattern. This can be done from various view points. The effects of both approaches are treated in the following sections.