Stress linearization

You can perform stress linearization on stress results from models composed of solid (continuum) elements such as CHEXA and CQUADX4 elements. Stress linearization decomposes the stress state along a line into membrane and bending stresses. You use a query curve to define the line, which is referred to as a stress classification line (SCL).

You can create a stress linearization before or after a model has been solved. Thus, if you identify an area of interest while post-processing your model, you can create a query curve from the post view display. After you return to the Simulation file, you can create a stress linearization for the query curve that you defined in the post view display without having to solve the model again.

Tip:

To create a query curve from a post view display, in the Post Processing Navigator, right-click Post View and choose New Query Curve.

After you create a stress linearization, the software lists it in the Simulation Navigator under the Stress Linearizations node. To edit, rename, or delete a stress linearization, right-click the node of the stress linearization and choose Edit, Rename, or Delete.

Because the actual stress does not necessarily vary linearly along the SCL, the sum of the linearized stresses does not generally equal the stress result. The difference between the stress result and the linearized stresses is referred to as the peak stress. The sum of the peak, membrane, and bending stresses equals the stress result at each point along the SCL.

Note:

Typically, only the peak stresses at the outermost fibers of the structural model are of interest as this is where the maximum bending stresses occur.

When the structure is modeled as axisymmetric, the SCL represents a surface.

For example, if the SCL is in the radial direction, the stress linearization is performed over a planar surface that is normal to the axis of the axisymmetric model. If the SCL is at an angle relative to radial direction, the stress linearization is performed over a conical surface.

Planar surface over which stress linearization is performed when the SCL is in the radial direction (1)	Conical surface over which stress linearization is performed when the SCL is at an angle relative to the radial direction (2)

Tip:

As a best practice, define the SCL normal to the midsurface of the cross section for which you want to obtain the membrane and bending stresses. Thus, you should generally avoid creating a SCL that creates a conical surface on a straight cylinder.

Whereas a SCL represents a surface in an axisymmetric model, in a (non-axisymmetric) 3D model, a SCL represents a line that passes through the model on which to decompose the stress state.

For more information on SCL, see Stress classification lines.

With the stress linearization capability, you can obtain stress results for models with solid elements that are directly comparable to the stress results that you would obtain if you modeled the structure with elements whose formulations account for membrane and bending stresses such as beam, plate, and shell elements. Thus, you can compare the stress results for models constructed of solid elements to design standards that are based on beam, plate, or shell stress results. The ASME Boiler & Pressure Vessel Code is an example of such a design standard.

To view the formulas that the software uses to compute the linearized stresses for axisymmetric models, see Stress linearization formulas for axisymmetric models.

To view the formulas that the software uses to compute the linearized stresses for 3D models, see Stress linearization formulas for 3D models.

After the software performs the stress linearization, you can display the numerical results in the Information window.

To use stress linearization on axisymmetric models, you must enable the StressLinearization_AxisymmetricStructure early access feature. For more information, see Enable an early access feature.

Where do I find it?

Create a stress linearization

Application	Pre/Post
Prerequisites	A solved structural model composed of solid elements with stress results
Command Finder	Stress Linearization

Display stress linearization results

Application	Pre/Post
Prerequisites	A solved structural model composed of solid elements with stress results and an existing stress linearization definition
Simulation Navigator	Under the Stress Linearization node→right-click Stress Linearization→Report

How do I

Perform stress linearization

Learn more

Stress classification lines

Stress linearization formulas for axisymmetric models

Stress linearization formulas for 3D models

Quick links

Command reference

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Stress linearization, Simcenter 3D 2021.1 Series

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