H μάζα είναι λογικά του αποσβεστή και το Κ είνα ΑΕ/L, αν και στο πρόγραμμα είναι η σταθερά του ελατηρίου. Για το Κ' (effective stiffness) είναι η παράμετρος για την μή γραμμική ανάλυση και επίσης το documentation οτι πρέπρει να ειναι 10^2 μέχρι 10^4.
"For the purposes of analysis, a linear effective stiffness is defined for each degree of freedom of the nonlinear elements. The effective stiffness at nonlinear degrees of freedom is arbitrary, but generally varies between zero and the maximum nonlinear stiffness of that degree of freedom. The equilibrium equation can then be rewritten as: Ku(t)+Cu'(t)+Mu''(t)=r(t)-[rN(t)-KN u(t)] whereK =KL +KN ,withKL beingthe stiffness of all the linear elements and for the linear degrees of freedom of the Link/Support elements,and KN being the linear effective-stiffness matrix for all of the nonlinear degrees of freedom.
Συγκεκριμένα για το στοιχείο που θέλω: IMPORTANT! You may sometimes be tempted to specify very large values for k, particularly for Damper, Gap, and Hook properties. Resist this temptation! If you want to limit elastic deformations in a particular internal spring, it is usually sufficient to use a value of k that is from 102 to 104 times as large as the corresponding stiffness in any connected elements. Larger values of k may cause numerical difficulties during solution. See the additional discussion for the Damper property below. "The linear effective stiffness represents the total elastic stiffness for the Link/Support element that is used for all linear analyses that start from zero initial conditions. The actual nonlinear properties are ignored for these types of analysisIf you do not specify nonlinear properties for a particular degree of freedom, then the linear effective stiffness is used for that degree of freedom for all linear and non- linear analyses.