ogstools.variables.integrity module

Functions related to stress based integrity analysis.

ogstools.variables.integrity.fluid_pressure_criterion(stress, pressure, biot=1.0)

Calculates the maximum effective principal stress.

The fluid pressure criterion is fulfilled when the third principal effective stress (minimum compressive stress / maximum tensile stress) is larger then the fluid pressure:

\[\sigma_\mathrm{III}' = \sigma_\mathrm{III}^\mathrm{tot} + \alpha_B \cdot p_\mathrm{fl} < 0\]

Return type:

ndarray

ogstools.variables.integrity.dilatancy_critescu(stress, pressure=None, a=-0.01697, b=0.8996)

Compute the dilatancy criterion.

Requires “sigma” and “pressure” to be in the mesh (in Pa).

For total stresses it is defined as:

\[F_{dil} = \frac{\tau_{oct}}{\sigma_0} - a \left( \frac{\sigma_m}{\sigma_0} \right)^2 - b \frac{\sigma_m}{\sigma_0}\]

For effective stresses it is defined as:

\[F'_{dil} = \frac{\tau_{oct}}{\sigma_0} - a \left( \frac{\sigma'_m}{\sigma_0} \right)^2 - b \frac{\sigma'_m}{\sigma_0}\]

<https://www.sciencedirect.com/science/article/pii/S0360544222000512?via%3Dihub>

Return type:

ndarray

ogstools.variables.integrity.dilatancy_alkan(stress, pressure=None, b=0.04, tau_max=33e6)

Compute the dilatancy criterion.

Requires “sigma” and “pressure” to be in the mesh (in Pa).

For total stresses it is defined as:

\[F_{dil} = \tau_{oct} - \tau_{max} \cdot b \frac{\sigma'_m}{\sigma_0 + b \cdot \sigma'_m}\]

For effective stresses it is defined as:

\[F_{dil} = \tau_{oct} - \tau_{max} \cdot b \frac{\sigma'_m}{\sigma_0 + b \cdot \sigma'_m}\]

<https://www.sciencedirect.com/science/article/pii/S1365160906000979>

Return type:

ndarray