The following parameters of the gap/hook model below are defined for positive arguments x>0. The value of the derivative needed to define the stiffness is also specified.
Function:
0 < x < D => f(x) = 0
x = D => f(x) = K1
Where:
K1 - final stiffness, which is estimated based on the stiffness of elements adjoining a given node and a value specified value of the stiffness parameter. The stiffness is evaluated by multiplying the stiffness of the model's degree of freedom at a node by the stiffness parameter. The default value for this parameter is 10000. Changing the value of this parameter is recommended only if there are problems with the convergence of a model, which results from the instability of the constraint determined by the model of rigidity with linear hardening. You can improve the convergence by reducing the value of the stiffness parameter, which mitigates discontinuity of the stiffness function.
Derivative (stiffness):
Limitations:
