Midas Civil Nonlinear Time History and Hysteresis Models
Definition
Midas Civil nonlinear time history and hysteresis models are the direct dynamic analysis procedures and inelastic component laws used when member, link, truss, or fiber behavior changes during a time-dependent load history.
How It Works
The manual describes nonlinear equations of motion, nonlinear static initialization, initial section-force consideration, initial stiffness options, and Newton-Raphson iteration with or without convergence calculation. Inelastic components include inelastic beams, inelastic General Links, and inelastic trusses.
Hysteresis options include bilinear, trilinear, tetralinear, origin-oriented, peak-oriented, Clough, Takeda-family, slip, Ramberg-Osgood, and Hardin-Drnevich models. Multi-axial hinge models include kinematic hardening and P-M or P-M-M interaction. Fiber models include steel and concrete constitutive models for section response.
Solver Development Notes
Time integration, nonlinear iteration, and hysteresis state update must share one accepted-state timeline.
Hysteresis laws need explicit unloading/reloading rules; a yield surface alone is not enough.
Multi-axial hinge interaction requires robust section-force mapping and yield-surface projection.
Fiber sections require material-point state management inside a member-level element.
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