Appendix D - MCT State Variables for Cohesive Materials

View specifics of the MCT state variables for cohesive materials.

The nine required state variables for Helius PFA cohesive materials are defined below. They are represented in ANSYS by SVARN where N is the unique integer which identifies the state variable (SVAR1, SVAR2, ... SVAR9).

SVAR1

The current damage state. This will be an integer between zero and 26. A value of zero indicates damage has not initiated yet. A value of 26 indicates complete failure (zero stiffness). Any other value indicates how much damage has been sustained. The states are incremented linearly starting at the effective displacement at damage initiation and ending at the effective displacement at complete failure. This state variable is used primarily as a tracking device for Helius PFA. In order to observe damage it is recommended to view the damage variable (SVAR6).

SVAR2

A continuous real variable between zero and one which indicates how much of the damage initiation criterion has been satisfied. A value of zero indicates no loads (or only normal compressive loads) are acting upon the integration point and therefore are not satisfying the damage initiation criterion. A value of one indicates damage has initiated and the stiffness is reducing.

SVAR3

The effective traction at damage initiation. The effective traction is defined as:

SVAR4

The effective displacement at damage initiation. The effective displacement is defined as:

SVAR5

The maximum effective displacement attained thus far in the loading history. The effective displacement is defined above.

SVAR6

The damage variable, D, a continuous real variable between zero and one which indicates how much damage has occurred. A value of zero indicates zero damage has accumulated and the stiffness of the integration point has not degraded any. A value of one indicates a fully damaged material and consequently zero stiffness.

SVAR7

The work done thus far in the normal loading mode (local 3-direction).

SVAR8

The work done thus far in the first shear loading mode (local 1-direction).

SVAR9

The work done thus far in the second shear loading mode (local 2-direction).