Hybrid simulation: OpenFresco

OpenFresco (the Open-source Framework for Experimental Setup and Control) is an environment-independent software framework, that connects finite element models with control and data acquisition systems in laboratories to facilitate hybrid simulation of structural and geotechnical systems.

Hybrid simulation is an experimental testing technique where a test is executed based on a step-by-step numerical solution of the governing equations of motion for a hybrid model, formulated considering both the numerical and physical portions of a structural system. In order for the earthquake engineering community to take full advantage of this technique, OpenFresco standardizes the deployment of hybrid simulation and extends its capabilities to applications where advanced numerical techniques are utilized, boundary conditions are imposed in real-time, and dynamic loading conditions caused by wind, blast, impact, waves, fire, traffic, and, in particular, seismic events are considered. Accordingly, the architecture of the OpenFresco software package provides a great deal of flexibility, extensibility, and re-usability to the researcher or developer interested in hybrid simulation.

OpenFrescoExpress is a self-contained software package, including a easy-to-use graphical user interface, that facilitates hybrid testing of systems having up to two degrees of freedom. OpenFrescoExpress addresses the needs of a wide range of users including:

• laboratory staff and research students learning about hybrid simulation and starting to use this experimental testing method.
• staff and students at laboratories that regularly use hybrid simulation but desire a tool for quick demonstration of the hybrid simulation testing method.
• researchers who are conducting simple tests and would like to take advantage of a graphical user interface that quickly and easily displays useful real-time test data.
• graduate students and researchers who are not at a laboratory but wish to run the software as a pure simulation tool to learn more about hybrid simulation and how it works.

OpenFresco is a robust middleware software package for performing hybrid simulations involving numerical models, test specimens, experimental setups and loading conditions that are larger and more complex than those considered by OpenFrescoExpress. It targets researchers, graduate students and laboratory staff that are more experienced in the concept and application of the hybrid simulation method. It is suited for advanced hybrid simulation when the users have analytical model and/or experimental specimen configurations that exceed the capabilities of the OpenFrescoExpress version, and/or have the desire and need to create their own custom graphical user interface.

OpenFresco and OpenFrescoExpress easily interface with many popular experimental control and data acquisition systems manufactured by dSpace, MTS (STS and FlexTest systems) National Instruments, SCRAMNet, Pacific Instruments and others. While OpenFrescoExpress contains its own analysis engine, OpenFresco can act as middleware enabling hybrid simulation using a wide variety of computational software packages, including: OpenSees, Matlab, Simulink, LS-DYNA, Abaqus, UI-SimCor, etc.

http://openfresco.berkeley.edu/