The Linearized Stress results calculate membrane, bending, peak, and total stress along a straight line path in the Mechanical application. To calculate linearized stress, you must first define a straight line path object using Construction Geometry under Model. A path you define for linearized stress can be of type Two Points or of type X axis Intersection and should have at least 47 sample points. The number of points must be an odd number: otherwise the result will not solve and an error message will be issued. The path must be straight and entirely within the model’s elements. The X axis Intersection option is recommend as it ensures that the start and end points are inside the mesh and that the path is straight. Note that the Two Points method obtains the points from the tessellation of the geometric model, and if the geometry faces are curved, the points might not be inside the mesh. For these situations, you can use the Snap to mesh nodes feature (see Path) to ensure that the two points are contained within the mesh.
Linearized stress does not support the Edge path type. To calculate linearized stresses:
In the object tree, select the Solution object.
On the Solution Context Tab, open the Linearized Stress drop-down menu and select your desired stress.
In the Details, select the Path you have defined to calculate the linearized stress.
Select the coordinate system you have used for the model.
As desired, for 3D analyses (only), set the Zero Through-Thickness Bending Stress property to to ignore out-of-plane bending stresses (SX, SXY, SXZ) in the linearized bending stress calculations.
Click Solve to calculate linearized stress along the path.
| Geometry | Select bodies that contribute toward stress calculation |
| Path | The path you define to calculate the linearized stresses |
| Type | Types of linearized stresses available |
| Coordinate System | Coordinate systems you can select for stress calculation |
About Linearized Stress
When the result is evaluated, component stress values at the path points are interpolated from the appropriate element's average corner nodal values. Stress components through the section are linearized by a line integral method and are separated into constant membrane stresses, bending stresses varying linearly between end points, and peak stresses (defined as the difference between the actual (total) stress and the membrane plus bending combination).
The Details shows Membrane, Bending, Membrane + Bending, Peak, and Total stresses. The bending stresses are calculated such that the neutral axis is at the midpoint of the path.
Principal stresses are recalculated from the component stresses and are invariant with the coordinate system as long as stress is in the same direction at all points along the defined path. It is generally recommended that calculations be performed in a rectangular coordinate system (global Cartesian).
The Details also includes the following three choices for the 2D Behavior (2D analysis only) property: Planar, Axisymmetric Straight, and Axisymmetric Curve. These choices are available only for 2D geometries (for example, plane stress).
For Axisymmetric Straight and Axisymmetric Curve, the Details includes entries for Average Radius of Curvature and Through-Thickness Bending Stress.
The Average Radius of Curvature represents the in-plane (X-Y) average radius of curvature of the inside and outside surfaces of an axisymmetric section. If the radius is zero, a plane or 3D structure is assumed. The curve radius is in the current units.
An Axisymmetric Straight analysis always has an infinite radius of curvature (which is denoted by a value of -1).
The choices for Through-Thickness Bending Stress are:
: Include the thickness-direction bending stresses.
: Ignore the thickness-direction bending stresses.
: Include the thickness-direction bending stress using the same formula as the Y (axial direction) bending stress. Also use the same formula for the shear stress.
If the Average Radius of Curvature is non-zero, Mechanical reports the linearized stresses in the section coordinates (SX – along the path, SY – normal to the path, and SZ – hoop direction). In this case, the choice of Coordinate System in the Details is ignored.
If the Average Radius of Curvature is zero, Mechanical reports the linearized stresses in the active results coordinate system.
For 3D geometries only, the property Zero Through-Thickness Bending Stress is displayed. It includes the following options:
(default): The application performs calculations as in previous revisions.
: When this option is selected, the bending stresses SX, SXY, SXZ are set to zero and the principal bending stress calculation for S1, S2, S3, SINT, and SEQV are performed using these zeroed components. The direction of the positive X-axis of the result’s Coordinate System must be the same as the direction of the specified Path (Start to End).
Notes on Linearized Stress
The line integral method is the same as that used in the Mechanical APDL command PRSECT, RHO, KBR, and KBR3D.
Mechanical does not support the Solution Coordinate System for this result.
The Worksheet reports the linearized component and principal stresses for each stress category at the beginning, mid-length, and end of the section path.