Not All at Once

I've been working on a project where we use OpenSees to analyze structural models for several load cases. We only care if the models can support the full load, not so much how they get to the full load. We apply all the load in one step with load control and Newton-Raphson. If that succeeds, … Continue reading Not All at Once →

It’s Not Load Control

The static integrators in OpenSees, including displacement control, arc length, and minimum unbalanced displacement norm (MUDN), are based on an incremental-iterative framework. After an initial load increment, each integrator imposes a constraint on the change in load factor at subsequent equilibrium iterations within a pseudo-time step. Displacement control calculates the change in load factor necessary … Continue reading It’s Not Load Control →