Members of the STAIRLab have recently contributed several improvements to the static integrators in OpenSeesRT. This notably includes implementing determinants in several important linear system classes, which allows integrators like ArcLength and MinUnbalDispNorm to correctly track equilibrium paths in nonlinear static continuation analysis. The improvements for the arc-length method are documented here.
A new example demonstrating these improvements has also been added to the STAIRLab gallery. This example reproduces the classic investigation of a shallow arch by Clark and Hancock, which wasn’t possible in OpenSees before these improvements. The example also showcases the animation capabilities of the STAIRLab’s veux library, which are documented here.
Deformed shape and load-deflection plot of a shallow arch simulated with OpenSeesRT
