isostatic surface

isostatic surface

[¦ī·sə′stad·ik ′sər·fəs]
(mechanics)
A surface in a three-dimensional elastic body such that at each point of the surface one of the principal planes of stress at that point is tangent to the surface.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.