Inconsistencies between post-processing and solver results

Post-processing reads only vector and tensor components from solver results files. It does not read any invariant results for vector or tensor quantities from the solver results files. Thus, inconsistencies can exist between invariant results calculated by post-processing and those calculated by the solver.

For example, when Simcenter Nastran is the solver, the following inconsistencies may exist:

• When two of the three principal stresses are equal, the directional cosines are not unique. For solid elements like CHEXA, Simcenter Nastran treats this as a special case and sets the directional cosines to zero, whereas post-processing calculates a pair of orthogonal principal directions for the repeated principal stresses.

• When using shell elements like CQUAD4, in the .f06 file:Simcenter Nastran lists the in-plane principal stresses as the major and minor principal stresses. Depending on the stress state, the major and minor principal stresses that Simcenter Nastran lists may not correspond to the maximum and minimum principal stresses that post-processing calculates for the three-dimensional stress state.Simcenter Nastran lists the in-plane maximum shear stress. Depending on the stress state, the in-plane maximum shear stress that Simcenter Nastran lists may not correspond to the maximum shear stress that post-processing calculates for the three-dimensional stress state.

• Simcenter Nastran does not output the out-of-plane normal stress and strain for shell elements like CQUAD4. As a result, post-processing uses zero for the out-of-plane normal stress and strain.For plane stress formulations of shell elements, this assumption may lead to errors in the invariant quantities for strain that post-processing calculates.For plane strain formulations of shell elements, this assumption may lead to errors in the invariant quantities for stress that post-processing calculates.

How do I

Select ply locations

Select shell locations

Learn more

Vector and tensor results

Complex results options

Cyclic worst principal stress and strain results

Grid point force and moment results

Shell locations

Shell resultants

Beam resultants

Element error results from adaptive analysis

Look up more details

Result types and results

Vector and tensor components and invariants

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

Browse Simcenter 3D help by product area

Inconsistencies between post-processing and solver results, Simcenter 3D 2021.1 Series

© 2020 Siemens

window.mainLanguage="en_US"

window.delivId=""

window.projectId=""

MathJax.Hub.Config({ TeX: { extensions: ["autoload-all.js"] }, tex2jax: { displayMath: [ ] }, "SVG": { scale: 125 } });