Composites

Composite Stress Toolbox

OptiStruct MATF cards are now supported by composite stress toolbox and certification calculation using first ply failure design point methods. This also enables first ply failure analysis for MAT9OR, which does not have allowables defined directly. Criteria are enabled or disabled in the design point method. Enabled criteria will use the MATF definition if defined and other allowables if not defined.

Failure Index (value of the failure function) has been added to the available result set, besides the already existing margin of safety, reserve factor, and inverse reserve factor.

Safety factors can now be incorporated into first ply failure and strength analysis.

• Design Safety Factor: F_eff = Design Safety Factor * F_applied
• Stability Factor: F_eff = Stability Factor * Design Safety Factor * F_applied

Tsai-Wu Parameter Support

Tsai-Wu parameter $F_{12}$ (OptiStruct/Nastran) and corresponding $F_{}^{*}$ are supported as per respective solver specifications. This replaces the previous fixed $F_{}^{*}=-0.5$ and correspondingly calculated $F_{12}$ .

Unified Back End API

A unified back end API has been added for both certification and composite stress toolbox model post-processing for improved performance.

First Ply Failure Results Have Moved

First ply failure results in the numerical result view have been moved above stress and strain results for faster access.

Hoffman 3D Failure Criteria Added

Hoffman 3D failure criteria has been added to the first ply failure method as per OptiStruct. See Hoffman Criteria in Hoffman Criteria for more information.

Preprocessing:

• In sequence entity integration, the following issues have been resolved:
  • Laminate review has been corrected if only children are sequences.
  • A ply is no longer marked as unused if used in sequence.
  • Drape table assignment to instance sequences has been corrected.
  • Element thickness now updates correctly after a change is made to sequence.
• The thickness of laminate no longer includes plies marked as inactive.
• The Composite Browser ply icon now updates to indicate if plies are hidden.
• Detailed ply layer visualization no longer fails if a laminate has more than two repeats.
• An error is no longer given if sub-laminates are dragged and dropped into an existing interface laminate.
• In the Shell to solid dialog, expected entities are now generated for all input settings.

Composite Stress Toolbox:

• Vast improvements have been made for supporting symmetric laminates in engineering constants, strength, and load response calculations for laminate entities (OptiStruct, Nastran, and Abaqus solver profiles). Vast improvements have also been made in element-based analyses including elements with PCOMP and PCOMPG properties (OptiStruct and Nastran solver profiles). Symmetric layers are labeled in numeric results and ply selections with an addition of “(SYM)” for layups based on unique ply identification, so essentially all except PCOMP.
• Contouring load response for PCOMPG relies on global ply ID instead of just layer index.
• In some cases, critical loads were not shown in strength analysis for iterative failure functions. This issue has been resolved. If the load factor has been increased by 2e32 or the Failure Index is below 1e-32, then the Inverse Reserve Factor is set to 0, which corresponds to reserve factor being infinite.
• Mid-plane strains and curvatures as well as homogenized mid-plane stresses are now reported correctly for elements with the offset not being mid-plane. Previously, ply stresses and strains as well as failure results have always been correct.