Midas Civil Boundary and Material Nonlinear Analysis
Definition
Midas Civil boundary and material nonlinear analysis is the incremental finite element workflow for nonlinear supports, nonlinear links, plastic material behavior, and path-dependent structural response.
How It Works
The analysis reference includes Newton-Raphson iteration, arc-length methods, P-Delta effects, boundary nonlinear analysis, material nonlinear analysis, and pushover-related workflows. Material nonlinearity is described through plasticity theory, constitutive matrices, stress integration, plastic material models, and hardening laws such as perfectly plastic, isotropic, kinematic, and mixed hardening.
Boundary nonlinearity appears through support or link behavior whose stiffness changes with force state, gap/contact status, or hysteretic rule. The nonlinear solve must therefore update both element state and boundary/link state across increments and iterations.
Solver Development Notes
Each nonlinear feature needs state variables, trial-state updates, accepted-state commits, and rollback behavior.
Newton methods require consistent residual, tangent, convergence norms, and line or increment control policies.
Arc-length control is a requirement when the load-displacement path passes limit points.
Boundary nonlinearities should share the same active-state and convergence infrastructure as material nonlinearities where possible.