Appendix B - State Variable Outputs

This section provides a list of the solution dependent state variable outputs produced by Advanced Material Exchange. There are a total of 21 state variables computed and updated by the Helius PFA user subroutine at each integration point in the model for fiber filled materials and 16 for unfilled materials. Some of the state variables may be unused depending on the features included in your analysis.

The finite element solver stores the converged values of the state variables in the same manner it stores values for typical element outputs such as stress and strain. A unique file (*.mct) is generated for each analysis. This file contains a complete list of the state variables that apply to your model. The *.mct file is the best reference for understanding the meaning of each state variable.

Abaqus State Variables (SDVs)

SDV Description
SDV1 Gauss point degradation status (1 = Not Ruptured, 2 = Ruptured)
SDV2 Element deletion status (1 = Active, 2 = Deleted)
SDV3 Local matrix 11 stress
SDV4 Local matrix 22 stress
SDV5 Local matrix 33 stress
SDV6 Local matrix 12 stress
SDV7 Local matrix 13 stress
SDV8 Local matrix 23 stress
SDV9 Matrix tangent modulus
SDV10 Matrix effective plastic strain
SDV11 Matrix effective stress
SDV12 Weld surface strength reduction factor. This variable is only applicable to analyses that have weld surfaces activated. It is useful for visualizing the location of weld surfaces in your part and understanding the reduction in strength applied to each element on the weld surface.
SDV13 Matrix failure criterion index. This variable is a continuous real variable that ranges from 0.0 to 1.0. It is used to indicate the fraction of the matrix failure criterion that has been satisfied. For example, when SDV13 = 0.0, the matrix stress state is zero. When SDV13 = 1.0, the matrix stress state has initiated failure. SDV13 is computed as the left hand side of Eq. 9 in The Rupture Model.
SDV14 Failure mode. SDV14 = 0 represents no failure, SDV14 = 1 represents a tensile failure, and SDV14 = 2 represents a compressive failure.
Note: If the material is forced to use a tensile response under compressive stress state, SDV14 will report the failure mode as tensile.
SDV15 Stress drop parameter μ for a failed integration point under a compressive stress state. SDV15 will range from 0.0 < μ ≤ 1.0.
SDV16

Fiber filled materials: Aspect ratio of the fiber.

Unfilled materials: Stress State. SDV16 = 1 represents a tensile dominated stress state and SDV16 = 2 represents a compressive dominated stress state.

SDV17 Fiber volume fraction
SDV18 1st eigenvalue of the fiber orientation tensor
SDV19 2nd eigenvalue of the fiber orientation tensor
SDV20 3rd eigenvalue of the fiber orientation tensor
SDV21 Stress State. SDV21 = 1 represents a tensile dominated stress state and SDV21 = 2 represents a compressive dominated stress state.

ANSYS State Variables (SVARs)

SVAR Description
SVAR1 Gauss point degradation status (1 = Not Ruptured, 2 = Ruptured)
SVAR2 For internal use only
SVAR3 Local matrix 11 stress
SVAR4 Local matrix 22 stress
SVAR5 Local matrix 33 stress
SVAR6 Local matrix 12 stress
SVAR7 Local matrix 13 stress
SVAR8 Local matrix 23 stress
SVAR9 Matrix tangent modulus
SVAR10 Matrix effective plastic strain
SVAR11 Matrix effective stress
SVAR12 Weld surface strength reduction factor. This variable is only applicable to analyses that have weld surfaces activated. It is useful for visualizing the location of weld surfaces in your part and understanding the reduction in strength applied to each element on the weld surface.
SVAR13 Matrix failure criterion index. This variable is a continuous real variable that ranges from 0.0 to 1.0. It is used to indicate the fraction of the matrix failure criterion that has been satisfied. For example, when SVAR13 = 0.0, the matrix stress state is zero. When SVAR13 = 1.0, the matrix stress state has initiated failure. SVAR13 is computed as the left hand side of Eq. 9 in The Rupture Model.
SVAR14 Failure mode. SDV14 = 0 represents no failure, SVAR14 = 1 represents a tensile failure, and SVAR14 = 2 represents a compressive failure.
Note: If the material is forced to use a tensile response under compressive stress state, SVAR14 will report the failure mode as tensile.
SVAR15 Stress drop parameter μ for a failed integration point under a compressive stress state. SDV15 will range from 0.0 < μ ≤ 1.0.
SVAR16

Fiber filled materials: Aspect ratio of the fiber.

Unfilled materials: Stress State. SVAR16 = 1 represents a tensile dominated stress state and SVAR16 = 2 represents a compressive dominated stress state.

SVAR17 Fiber volume fraction
SVAR18 1st eigenvalue of the fiber orientation tensor
SVAR19 2nd eigenvalue of the fiber orientation tensor
SVAR20 3rd eigenvalue of the fiber orientation tensor
SVAR21 Stress State. SVAR21 = 1 represents a tensile dominated stress state and SVAR21 = 2 represents a compressive dominated stress state.

Nastran Results

Nastran results are identified with normal result labels as opposed to state variable numbers.

Result Description
DAMAGE STATE Gauss point degradation status (1 = Not Ruptured, 2 = Ruptured)
MATRIX TANGENT MODULUS The tangent elastic modulus of the matrix constituent.
MATRIX EFFECTIVE PLASTIC STRAIN The effective plastic strain of the matrix constituent.
MATRIX EFFECTIVE STRESS The effective stress of the matrix constituent.
WELD SURFACE STRENGTH REDUCTION FACTOR This result is only applicable to analyses that have weld surfaces activated. It is useful for visualizing the location of weld surfaces in your part and understanding the reduction in strength applied to each element on the weld surface.
FAILURE INDEX This result is a continuous real variable that ranges from 0.0 to 1.0. It is used to indicate the fraction of the matrix failure criterion that has been satisfied.0.0 = the matrix stress state is zero. 1.0 = the matrix stress state has initiated failure. This result is computed as the left hand side of Eq. 9 in The Rupture Model.
FAILURE MODE Failure mode. 0 represents no failure, 1 represents a tensile failure, and 2 represents a compressive failure.
Note: If the material is forced to use a tensile response under compressive stress state, the failure mode is reported as tensile.