About the Linearization Basis
The linearization basis is a coordinate system that gives the X, Y and Zdirections to calculate the linearized stress for a selected line segment. It appears as a vector triad at the midpoint of the linearization segment.
Use the Basis list on the Linearized Stress Report dialog box to select a method to define the linearization basis:
• Defined by Curvatures—This option is available only if the Point 2 is defined by On Opposite Surface. The linearization basis is defined by the directions of principal curvature of the first surface. In this case, the Xdirection is the surface normal, the Ydirection is the direction of maximum curvature and the Zdirection is the direction of minimum curvature.
For 2D models, the Zdirection is normal to the plane of the model, the Xdirection is normal to the boundary curve and the Ydirection is perpendicular to X and Z.
• Defined by Stress Values—The default option for flat surfaces (curvature =0) or surfaces with uniform curvature (spherical surfaces). The linearization basis is defined using the YY stress component. In this case X is the direction from point 1 to point 2; Y is the direction perpendicular to X that maximizes the YY stress component at point 1. Z is perpendicular to the XY plane.
• Defined by Point—Select a point using the Points Selection collector. The point must not be collinear with the linearization segment. The selected point along with the linearization segment defines the XY plane. The Xdirection is from Point 1 to Point 2. The Z and Ydirections are determined by the right hand rule.

Linearization basis is not available for 2D models.
