Problem description

The Plaxis Sensitivity Analysis & Parameter variation (SensiPar) displays and uses the parameters λ* (lambda*) and κ* (kappa*), instead of the parameters λ (lambda) and κ (kappa), as is used in the Material Dataset definition.

The relationship between these parameters is:

κ* = κ / (1 + e_init)
λ* = λ / (1 + e_init)

When reading the initial values from the Input program, Sensipar will convert the parameter values according to λ* and κ*. Sensipar will send the parameter values λ* (lambda*) and κ* (kappa*) as displayed in Sensipar to the Input program when running the analyses in Sensipar. For the calculation these parameters λ* (lambda*) and κ* (kappa*) will then be converted in Plaxis again so Plaxis will use again the appropriate values for λ (lambda) and κ (kappa).

Solution

This issue is now solved since PLAXIS 2D 2017.01

For now, users are advised to define λ* and κ* for the values for the minimum, maximum and reference values in SensiPar when choosing the parameters in the Select parameters tab. Note that the initial value is converted correctly from λ/κ to λ*/κ*.

The parameters can be easily be computed as:
κ* = κ / (1 + e_init)
λ* = λ / (1 + e_init)