Analysis Model for Nonlinear Hinges

Form: Analysis Model for Nonlinear Hinges

Use the Analyze menu > Analysis Model for Nonlinear Hinges command to access the Analysis Model for Nonlinear Hinges form and select which type of hinge formulation should be used when assembling the model.

Model Hinges Within Elements: Choose this option if the hinges should be integral (internal) within frame and wall objects. These hinges may be used in static and direct integration nonlinear analyses.
Model Hinges as Separate Link Elements (Permits FNA): Choose this option if the hinges should be modeled in frames and walls using an additional link element. These hinges may be used in all nonlinear analyses, including the often faster and more stable Fast Nonlinear Analysis (FNA).

Note: There may be slight differences in results between these two options due to minor variations in flexibility and inertia.

Stiffness-proportional Damping for Hinges in Link Elements options. This area of the form is available when the hinges are modeled as separate link elements. Select the type of damping:

Proportional to Initial Stiffness (K0): Damping is based on the initial stiffness. This results in faster execution times, but may overestimate the damping.
Proportional to Tangent Stiffness (KT): Damping is based on the tangent stiffness. This technique is computationally more intensive, but provides realistic damping levels. This is the default option.
Mixed: F0 * K0 + (1 - F0) * KT: Damping is based on a ratio of the two damping techniques described above. Enter the fraction of Initial Stiffness, F0, into the edit box. The acceptable range for F0 is 0 ≤ F0 ≤ 1.

Note: Proportional damping applies to the entire model and to every direct-integration time-history load case where hinges are active.