In a geometric description of a shell section, an offset between the centres of its inner and outer contours.
Also called: capsule eccentricity; shell off-centering; Shell eccentricity.
Is an eccentric shell necessarily oval?
No. In an ideal circular hollow section, both boundaries can be circular while their centres differ. Exterior ovality instead describes the outer section’s shape. Centre offset and noncircular shape are separate geometric quantities.
For an actual shell, identify the inspected region and obtain both inner and outer contours. The ideal-circle model clarifies the geometry, but an outside-diameter reading alone cannot locate the inner boundary.
Can any thickness variation be converted to eccentricity?
Only with the definition and geometric assumptions explicit. Normalising centre offset by a radius difference is one hollow-section convention, not a capsule standard. Real shell profiles can include noncircularity, local features and intentional regional thickness changes.
Report the metric, units, section and contour-fitting method with local thickness data. An irregular shell may not fit the ideal-circle model, and eccentricity limits from shafts or seamless capsules do not define limits for a two-piece shell.