Material strength limits represent maximum stresses or strains
that a material can sustain. This data table defines the strength
limits and other related constants required for computing failure
criteria (FC) index of a material under various loading conditions.
Specify a TBOPT value on the TB,FCLI command
to correspond to the stress limits (TBOPT = 1) or strain limits (TBOPT = 2). The
following table lists the coefficient values that are addressed for
the available TBOPT values:
| Strength Limit Constants | TBOPT = 1 | TBOPT = 2 |
|---|---|---|
| Stress Limits (NPTS = 16) | Strain Limits (NPTS = 9) | |
| C1 | XTEN -- Allowable tensile stress in material X-direction (must be positive) | XTEN -- Allowable tensile strain in material X-direction (must be positive) |
| C2 | XCMP -- Allowable compressive stress in material X-direction (default to the negative of XTEN) | XCMP -- Allowable compressive strain in material X-direction (default to the negative of XTEN) |
| C3 | YTEN -- Allowable tensile stress in material Y-direction (must be positive) | YTEN -- Allowable tensile strain in material Y-direction (must be positive) |
| C4 | YCMP -- Allowable compressive stress in material Y-direction (default to the negative of YTEN) | YCMP -- Allowable compressive strain in material Y-direction (default to the negative of YTEN) |
| C5 | ZTEN -- Allowable tensile stress in material Z-direction (must be positive) | ZTEN -- Allowable tensile strain in material Z-direction (must be positive) |
| C6 | ZCMP -- Allowable compressive stress in material Z-direction (default to the negative of ZTEN) | ZCMP -- Allowable compressive strain in material Z-direction (default to the negative of ZTEN) |
| C7 | XY -- Allowable XY shear stress (must be positive) | XY -- Allowable XY shear strain (must be positive) |
| C8 | YZ -- Allowable YZ shear stress (must be positive) | YZ -- Allowable YZ shear strain (must be positive) |
| C9 | XZ -- Allowable XZ shear stress (must be positive) | XZ -- Allowable XZ shear strain (must be positive) |
| C10 | XYCP -- XY coupling coefficient for Tsai-Wu strength index (default = -1.0) | -- |
| C11 | YZCP -- YZ coupling coefficient for Tsai-Wu failure index (default = -1.0) | -- |
| C12 | XZCP -- XZ coupling coefficient for Tsai-Wu failure index (default = -1.0) | -- |
| C13 | XZIT -- XZ tensile inclination parameter for Puck failure index (default = 0.0) | -- |
| C14 | XZIC -- XZ compressive inclination parameter for Puck failure index (default = 0.0) | -- |
| C15 | YZIT -- YZ tensile inclination parameter for Puck failure index (default = 0.0) | -- |
| C16 | YZIC -- YZ compressive inclination parameter for Puck failure index (default = 0.0) | -- |
| C17 | G1G2 -- Fracture toughness ratio between GI (mode I) and GII (mode II) | -- |
| C18 | ETAL -- Longitudinal friction coefficient | -- |
| C19 | ETAT -- Transverse friction coefficient | -- |
| C20 | ALP0 -- Fracture angle under pure transverse compression | -- |
To determine physical failure criteria in unidirectional fiber-reinforced composite materials, including Puck and Hashin, LaRc03, and LaRc04 criteria, always define the reinforced fiber direction as the material X direction.
The following table summarizes the applicable strength-limit constants for each failure criterion:
| Strength Limit Constants | Max Strain Criterion | Max Stress Criterion | Tsai-Wu Strength Ratio | Puck Criterion | Hashin Criterion | LaRc03/04 Criterion | User-Defined |
|---|---|---|---|---|---|---|---|
| C1 | Y | Y | Y | Y | Y | Y | Y |
| C2 | Y | Y | Y | Y | Y | Y | Y |
| C3 | Y | Y | Y | Y | Y | Y | Y |
| C4 | Y | Y | Y | Y | Y | Y | Y |
| C5 | Y | Y | Y | -- | -- | -- | Y |
| C6 | Y | Y | Y | -- | -- | -- | Y |
| C7 | Y | Y | Y | Y | Y | Y | Y |
| C8 | Y | Y | Y | -- | Y | -- | Y |
| C9 | Y | Y | Y | -- | -- | -- | Y |
| C10 | -- | -- | Y | -- | -- | -- | Y |
| C11 | -- | -- | Y | -- | -- | -- | Y |
| C12 | -- | -- | Y | -- | -- | -- | Y |
| C13 | -- | -- | -- | Y | -- | -- | Y |
| C14 | -- | -- | -- | Y | -- | -- | Y |
| C15 | -- | -- | -- | Y | -- | -- | Y |
| C16 | -- | -- | -- | Y | -- | -- | Y |
| C17 | -- | -- | -- | -- | -- | Y | Y |
| C18 | -- | -- | -- | -- | -- | Y | Y |
| C19 | -- | -- | -- | -- | -- | Y | Y |
| C20 | -- | -- | -- | -- | -- | Y | Y |